NEW ESSAYS 



CONCERNING 



HUMAN UNDERSTANDING 



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NEW ESSAYS 



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HUMAN UNDERSTANDING 



GOTTFRIED WILHEHM LEIBNITZ 

TOGETHER WITH 

AN APPENDIX 

CONSISTING OF SOME OF HIS SHORTER PIECES 



TRANSLATED FROM THE ORIGINAL LATIN, FRENCH 
AND GERMAN, WITH NOTES 



ALFRED GIDEON LANGLEY 

A.M. (Brown) 

. AUG? ©?aw 

Neto fork 
THE MACMILLAN COMPANY 

LONDON: MACMILLAN & CO., Ltd. 

1896 

All rights reserved 



*£S 



THE LIBRARY 
Or CONGRESS 

WASHINGTON 



Copyright, 1896, 
By THE MACMILLAN COMPANY. 



NortooDlt $msg 

Cushing & Co. — Berwick & Smith 
Norwood Mass. U.S.A. 






Ea mg fflatytx ano Sister 

SOMETIME GONE WHERE WE SHALL KNOW AS WE ARE KNOWN 

&ttD to tug jfatjjet 

STILL WHERE WE SEE AS IN A MIRROR OBSCURELY 

IN DEEPEST LOVE AND GRATITUDE 

I DEDICATE THIS BOOK 



CONTENTS 



Translator's Preface xi 

Gerhardt's Introduction to his edition of Leibnitz's Nouveaux 

Essais 3 

LEIBNITZ'S CRITIQUE OF LOCKE 

On Locke's Essay on Human Understanding, 1696 .... 13 
Specimen of Thoughts upon the First Book of the Essay on Human 

Understanding, 1698 . .' 20 

Specimen of Thoughts upon the Second Book, 1698 .... 23 
On Coste's Translation of Locke's Essay concerning Human Under- 
standing ; from the "Monatliche Auszug," September, 1700, 

pp. 611-636 26 

Addition thereto. " Monatliche Auszug," 1701, pp. 73-75 . . 37 

New Essays on The Understanding, by the Author of the 
System op Pre-established Harmony 

Preface 41 

Book I. — Innate Ideas 

CHAPTER 

I. Are there innate principles in the mind of man ? . . .64 
II. No innate practical principles ....... 85 

III. Other considerations touching innate principles, both spec- 
ulative and practical 100 

Book II. — Ideas. 



I. Which treats of ideas in general, and examines by the way 
whether the mind of man always thinks . 

II. Simple ideas 

HI. Of ideas which come to us by one sense only . 

IV. Of solidity 

V. Of simple ideas which come by different 
VI. Of simple ideas which come by reflection 
vii 



109 
120 
121 
122 
129 
130 



CONTENTS 



CHAPTER 

VII. 

VIII. 

IX. 

X. 

XI. 

XII. 

XIII. 

XIV. 

XV. 

XVI. 

XVII. 

XVIII. 

XIX. 

XX. 

XXI. 

XXII. 

XXIII. 

XXIV. 

XXV. 

XXVI. 

XXVII. 

XXVIII. 

XXIX. 

XXX. 

XXXI. 

XXXII. 

XXXIII. 



I. 

II. 

III. 

IV. 
V. 
VI. 
VII. 
VIII. 
IX. 
X. 
XI. 



PAGE 

Of ideas which come by sensation and reflection . . 130 

Other considerations upon simple ideas .... 130 

Of perception 135 

Of retention . . . _ 142 

Of discernment, or the faculty of distinguishing ideas . 143 

Of complex ideas 147 

Of simple modes, and first of those of space . . . 149 

Of duration and its simple modes 155 

Of duration and expansion considered together . . 158 

Of number 100 

Of infinity 161 

Of other simple modes 164 

Of the modes of thinking 164 

Of modes of pleasure and pain 167 

Of power and freedom 174 

Of mixed modes 221 

Of our complex ideas of substances 225 

Of collective ideas of substances 235 

Of relation 235 

Of cause and effect and some other relations . . . 237 

What identity or diversity is . . . - . . 238 

Of some other relations, and especially of moral relations 258 

Of clear and obscure, distinct and confused ideas . . 265 

Of real and fantastical ideas 275 

Of adequate and inadequate ideas ..... 278 

Of true and false ideas ....... 281 

Of the association of ideas ...... 281 

Book III. — Words. 

Of words or language in general 285 

Of the signification of words 291 

Of general terms 307 

Of the names of simple ideas 318 

Of the names of mixed modes and relations . . . 325 

Of the names of substances 330 

Of particles ' 364 

Of abstract and concrete terms . . . . . 368 

Of the imperfections of words 369 

Of the abuse of words 376 

Of the remedies which may be applied to the imperfec- 
tions and abuses just spoken of . . . . . 390 



CONTENTS 



Book IV. — Of Knowledge 

CHAPTER PAGE 

I. Of knowledge in general 397 

II. Of the degrees of our knowledge 404 

III. Of the extent of human knowledge 423 

IV. Of the reality of our knowledge 444 

V. Of truth in general 449 

VI. Of universal propositions, their truth and certitude . . 452 

VII. Of propositions called maxims or axioms .... 462 

VIII. Of trifling propositions 490 

IX. Of our knowledge of our existence 497 

X. Of our knowledge of the existence of God .... 449 

XL Of our knowledge of the existence of other things . .511 

XII. Of the improvement of our knowledge . . . .517 

XIII. Other considerations concerning our knowledge . . 528 

XIV. Of judgment 528 

XV. Of probability 529 

XVI. Of the degrees of assent 532 

XVII. Of reason ... 555 

XVIII. Of faith and reason and their distinct limits . . . 583 

XIX. Of enthusiasm 596 

XX. Of error 607 

XXI. Of the division of the sciences 621 



APPENDIX 

I. Leibnitz to Jacob Thomasius. April 20-30, 1669 . . .631 
II. Fragment, (c. 1671) 651 

III. Demonstration against atoms taken from the contact of 

atoms. (October, 1690) 652 

IV. Essay on Dynamics on the laws of motion, in which it is 

shown that not the same quantity of motion is preserved, 
but the same absolute force, or rather the same quantity 
of moving action (Taction motrice). (c. 1691) . . 657 
V. Essay on Dynamics in defence of the wonderful laws of 
nature in respect to the forces of bodies, disclosing their 
mutual actions and referring them to their causes. 

Part I. 1695 670 

lb. Part II. 1695 684 

VI. On the radical origin of things. 1697 692 

VII. Appendix to a letter to Honoratus Fabri. 1702 . . . 699 



x CONTENTS 

PAGE 

VIII. Letter of Leibnitz to Basnage de Beauval, editor of the 
" Histoire des Ouvrages des Savants," printed in that 

journal, July, 1698, pp. 829 sq 706 

IX. Fragment of a letter to an unknown person. 1707 . . 712 

X. That the most perfect Being exists ...... 714 

XL What is idea 716 

XII. On the method of distinguishing real from imaginary phe- 
nomena 717 

Additions and Corrections 721 

Index A. To the Critique of Locke ...... 777 

Index B. To the Appendix 823 

Index C. To the Notes, Additions, and Corrections . . . 831 



TRANSLATOR'S PREFACE 



The work herewith given to the public consists of a transla- 
tion of the entire fifth volume of Gerhardt's Die phUosopliischen 
Schriften von G. W. Leibniz, sub-entitled "Leibniz und Locke," 
consisting of an Introduction by Gerhardt, several short pieces 
on Locke's Essay and the New Essays on Human Under- 
standing ; and of an Appendix containing a translation of 
other short pieces of Leibnitz bearing on the subjects dis- 
cussed in the New Essays or referred to therein. The Intro- 
duction on The Philosophy of Leibnitz by the translator 
suggested and urged by Professors Palmer and Eoyce of Har- 
vard University, and for some time contemplated, is deferred, 
and reserved, if at all, for another time and occasion, owing 
to the size of the present volume, as well as for other good 
and sufficient reasons which it is not necessary here to 
mention. 

The translation of Leibnitz's Nouveaux Essais sur VEntende- 
ment Humain was first suggested by the following sentence 
of the late Professor George S. Morris, of the University of 
Michigan, in a note to his Pliilosophy and Christianity, page 
292: "It suggests no favorable comment on the philosophic 
interest of the countrymen of Locke that the above-mentioned 
reply of Leibnitz to Locke has never (so far as I can ascertain) 
been translated into English." Four instalments, consisting 
of Book I. and Book II., chapters 1-11 inclusive, were pub- 
lished in as many numbers of the "Journal of Speculative 
Philosophy. " * Professor Morris very kindly sent me a care- 
ful criticism of about one-third of the first instalment, with 
valuable suggestions regarding the further work of transla- 
tion. His corrections and suggestions received careful con- 

i Vol. 19, No. 3, July, 1885; Vol. 21, No. 3, July, 1887; Vol. 21, No. 4, Octo- 
ber, 1887 ; Vol. 22, No. 2, April, 1888. 

xi 



TRANSLATOR'S PREFACE 



sideration and were embodied in subsequent revisions of the 
translation in preparing it for the present issue. 

The portion of the New Essays thus published being 
favorably received by professors and students of philosophy 
in this country and in Europe, and being encouraged to go on 
and translate the entire piece, the work begun in 1885 was 
continued in leisure hours until in June, 1891, the translation 
was completed. Revision, annotation, and the labor of get- 
ting it through the press have occupied the greater part of my 
free time since then. The annotation, which was not a part 
of the original plan, but which was found to be desirable, if 
not even necessary, as the sheets began to appear in type, has 
been the chief cause of the delay in the appearance of the 
book, the labor involved therein proving far greater and una- 
voidably more protracted than was expected, the annotation 
also, as is frequent in such cases, growing with the progress 
of the book. 

The text-basis of the translation is that of C. I. Gerhardt, 
in his Die philosophischen Schriften von G. W. Leibniz, 7 vols., 
Berlin, 1875-1890, except for the Dynamical Pieces in the 
Appendix, Nos. IV., V., the text-basis of which is C. I. Ger- 
hardtfs Leibnizens mathematische Schriften, Berlin and Halle, 
1849-1863, and Appendix No. VII., for which both these 
editions are used; for Appendix No. IX., the text is that 
given by Guhrauer, G. W. Freiherr v. Leibnitz. Eine Biographie, 
Breslau, 1846. The other editions used in the comparison of 
the text and the preparation of the notes are: J. E. Erd- 
mann, Leibnitii Opera Philosophica, Berlin, 1839-1840; M. A. 
Jacques, CEuvres de Leibniz, Paris, 1842; P. Janet, (Euvres 
PMlosophiques de Leibniz, Paris, 1866; Dutens, Leibnitii Opera 
Omnia, Geneva, 1768; Foucher de Careil, Lettres et Opuscides 
inedits de Leibniz, Paris, 1854, Nouvelles Lettres et Opuscides 
de Leibniz inedits, Paris, 1857, and (Euvres de Leibniz, Paris, 
1859 sq., 2d ed., Paris, 1867 sq. R. E. Raspe, (Euvres Philoso- 
phiques de feu Mr. Leibnitz, Amsterdam and Leipzig, 1765, was 
received too late to be of service, but as his text is the original 
printed text of the New Essays, and has been used by all sub- 
sequent editors, it is not probable that any important variation 
of reading has been overlooked; and Raspe's text has no notes. 
Besides these editions of Leibnitz's Works, the German trans- 



TRANSLATOR'S PREFACE 



lations of the Theodicee and of the smaller philosophically- 
important works entitled Die Meineren philosophisch wichtigeren 
Schriften by J. H. von Kirchmann, in his Philosophische 
Bibliothek, Berlin, 1879, and the English translation of his 
important philosophical opuscules by Professor George M. 
Duncan of Yale University, entitled The Philosophical Works 
of Leibnitz, New Haven, 1890, have been consulted. From 
the last-named work, so as to include in one book all of Leib- 
nitz's discussions of Locke, it was at first intended to reprint 
in the Appendix all the pieces bearing upon the subject dis- 
cussed in the New Essays, or especially referred to therein. 
It finally seemed best to both Professor Duncan and myself 
to change the plan and translate new material, rather than 
duplicate that already translated, so that with the exception 
of Appendix No. VI., Professor Duncan's translation of which 
was either forgotten or unnoticed till after mine was in type, 
nothing appears in both books save such portions of the New 
Essays .as he has included, and the piece entitled On Locke's 
Essay on Human Understanding, 1696. This statement will 
explain the references in certain notes, for example, page 101, 
note 1, page 154, note 1 (cf. infra, pages 737 and 749 respec- 
tively), to certain pieces of Leibnitz in the Appendix, which 
references are corrected in the Additions and Corrections by 
being changed to the proper pages of Professor Duncan's 
book. 

Of great value in the revision of the translation, and of the 
greatest service in the preparation of the notes, has been the 
German translation of the Nouveaux Essais, with notes, by 
Professor Carl Schaarschmidt of the University of Bonn. 
His material has been freely used, either by direct translation 
and quotation, or in substance, in the notes of the present edi- 
tion, though always, so far as possible, only after verification 
and further independent study. His notes, I regret to say, 
contain many numerical errors, occasioned presumably by in- 
sufficient care and accuracy in proof-reading; otherwise they 
are, for the most part, accurate. The fact that Professor 
Schaarschmidt' s book was not received till after a portion of 
mine was in type accounts in part for the appearance of so 
much of his note-material in the Additions and Corrections, 
rather than in its proper place in the foot-notes to the text. 



TRANSLATOR'S PREFACE 



Professor A. C. Frazer's splendid edition of Locke's Essay, 
Oxford, 1894, did not appear until after most of the New 
Essays were in type; and P. Coste, Essai pliilosophique con- 
cernant V Entenclement humain — par M. Locke, Amsterdam, 
1742, 1 vol., 4to, 1774, 4 vols., 12mo, could not be obtained, 
until all the New Essays and most of the Appendix were in 
type. Both of these works, therefore, could be used only in 
the supplementary notes in the Additions and Corrections. 

With regard to the text itself, particularly of the New Essays, 
a few words may not be out of place. The variations are slight 
and chiefly verbal, and scarcely ever essentially modify the 
thought. They are ultimately due either to the manuscript of 
Leibnitz — which Erdmann (Preface, p. xxii) says is " written 
in such small characters often, and so full of corrections, that 
it is very difficult to read it" ("tarn parvis ssepe Uteris con- 
scriptum et correctionibus adeo abundans ut perdifficile lectu ") 
— or to certain changes made for the purpose of improving the 
literary style of the author, and of thus making his work more 
acceptable to his French readers. The chief difference between 
the text as given by Gerhardt, who has compared his impres- 
sion "with the original, so far as it is still extant," and that 
of the other editors consists in a transposition of the text in 
Book I., chap. I., a transposition which is fully indicated in 
the note at the point in the text of the translation where it 
occurs, and which is, I suppose, due to Gerhardt' s fidelity to 
Leibnitz's original text. All the important textual variations 
are listed in the notes. 

Gerhardt' s text, having been compared with the original, 
seems the most trustworthy, and accordingly has been followed 
in this translation, excepting in a few instances mentioned in 
the notes, where it is manifestly erroneous from inaccurate 
proof-reading or other cause, and where the text of some other 
editor seemed more consistent or correct. Gerhardt has intro- 
duced into his text the brackets, [ ], in which, " in the original, 
Leibnitz has enclosed the words of Philalethes, who states the 
views of Locke," "perhaps as an indication that they are not 
his own;" and I have introduced them into the translation 
precisely as they stand in the text of Gerhardt, in order that 
the translation may conform to and represent as perfectly as 
possible Leibnitz's original text in its integrity. There seems 



TRANSLATOR'S PREFACE 



to be, however, little regularity or consistency in the employ- 
ment of these brackets, so far, at least, as I can discover upon 
comparison with Locke's treatise. 

Besides the editions and translations already named, the 
various separate editions of single works of Leibnitz, as also 
the various discussions of his philosophy, theology, etc., and 
the monographs on different parts of the same, were occasion- 
ally consulted or referred to, so far as these were accessible 
or could be procured. Among the monographs, especial men- 
tion should be made of Professor John Dewey's most excellent 
Leibniz's New Essays concerning the Human Understanding. 
A Critical Exposition, 1888, in the series of German Philo- 
sophical Classics edited by Professor George S. Morris, and 
published by S. C. Griggs & Co., Chicago; and of the earlier 
monograph of G. Hartenstein, Locke's Lehre von der menscli- 
lichen Erkenntniss in Vergleiclmng mit Leibniz's Kritik derselben, 
Leipzig, 1861. 

The translation has purposely been made close rather than 
free, a philosophical treatise seeming properly to require a 
closer adherence on the part of the translator to the author's 
form of thought and expression than a history, novel, or poem. 
Whatever view may be taken on this point, — and I frankly 
admit that at least two views are possible and that each method 
of translation has its advantages and its disadvantages, its 
perils and its successes, — the form and style of the New Essays 
make an elegant and forceful translation well-nigh impossible. 
Such a translation would necessitate the entire re-writing of 
Leibnitz's work, would, in fact, be a reproduction rather than 
a translation, a task I have not attempted nor felt it incumbent 
on me to attempt. My aim has been simply to represent as 
faithfully and as accurately as possible, and in as good English 
as its form and expression admitted, Leibnitz's exact thought. 
The style of Leibnitz in the New Essays, especially in the 
abbreviations or abstracts of Locke's Essay put into the mouth 
of Philalethes, is often abrupt and obscure and sometimes 
even un grammatical (c/., for example, New Essays, Book III., 
chap. II., § 18, page 392, lines 6 and 7, and the note thereto, 
infra, page 768 ad Jin.). This condition of things is due partly 
to the form of the work, but chiefly to the method of its com- 
position (cf. Gerhardt's introduction, infra, page 8, and notes, 



TRANSLATOR'S PREFACE 



and the letters of Leibnitz cited by Raspe in Ms Preface, page 
12, note 6, and which he says, " I found with the manuscript 
of the New Essays," and "give as I found them "). A work so 
written, in spite of more or less revision, could not possibly 
be a finished treatise or a work of literary art like the Dia- 
logues of Plato, and the character of the work must of neces- 
sity be reflected in the translation. 

The notes aim to give the desirable or necessary biographical 
and bibliographical information regarding the persons and 
books referred to in the course of the work, so far as such 
information could be obtained; references to other pieces of 
Leibnitz, and occasionally to other authors, where the same 
topic is discussed; and explanations of a few terms thought 
to be obscure and the explanations of which are not generally 
known or easily accessible. The notes do not pretend to be a 
commentary on the text. Except in a few cases, the reader 
or student has purposely been left to gain his knowledge of 
Leibnitz's views from Leibnitz himself. Extended com- 
mentary was impossible within the necessary limits of the 
volume, and accordingly was not included in the plan. The 
philosophical notes, therefore, confine themselves to a brief 
statement of Leibnitz's views and to brief criticism or indica- 
tion of criticism. The aim was to bring Leibnitz's great work 
within the reach of English students and to render it more 
easily accessible, with such annotation, literary and other, as 
would make it more acceptable to the student. 

All material taken from other authors has, so far as pos- 
sible, been verified and made the subject of such independent 
study as the case seemed to demand. All references to 
authorities have been verified when possible, and very great 
pains have been taken to secure perfect accuracy in all refer- 
ences. The citations have uniformly been taken and the 
references made to the best editions, and usually to the latest, 
when these editions were accessible. Occasionally other works 
or editions are referred to because of their accessibility or for 
other evident reasons. For the convenience of those possess- 
ing different editions of Leibnitz's works, as well as for those 
who may have access to only one of them, reference is usually 
made, especially in the earlier notes, to all of the editions. 
Later this procedure seemed to encumber the notes with an 



TRANSLATOR'S PREFACE 



unnecessary amount of numerical reference, and it was for the 
most part discontinued. 

Attention is called to the Additions and Corrections as 
containing matter of importance, most of which was not 
obtained till after the portion of the hook to which it refers 
was already in type, and which, therefore, could not be 
inserted in its proper place in the book, but had to be reserved 
to the end. 

The Indexes are intentionally full and complete and have 
been made with great care by Rev. Robert Kerr Eccles, M.D. 
There is no adequate index to Leibnitz's works, and none 
whatever exclusively devoted to the New Essays. The refer- 
ences thereto in the meagre index in Raspe's edition of the 
Philosophical Works, not generally accessible, and in the 
general index, full as it is, in Erdmann's edition, are by no 
means sufficient. It is hoped that the Indexes here furnished 
may prove adequate for the works of Leibnitz included in this 
volume, and that thus a beginning at least of an adequate index 
to Leibnitz's complete works shall have been made. 

In Appendix No. IV., infra, page 663, and No. V., infra, 
pages 674, 682, and 686, the numbering of the cuts is changed 
from that of the original text to conform to their proper 
numerical order in this book. The fact is here noted to pre- 
vent confusion in referring to the original. 

I gratefully acknowledge my obligations and express my 
thanks to all who have aided me in my long and arduous work. 
Especially to President E. B. Andrews of Brown University, 
for aid in the note on the term "quarto modo," page 455, 
and for the verification of references; to Professor Albert G. 
Harkness of Brown University, for aid in locating some of 
the Latin quotations in the New Essays; to Professor J. E. 
Jameson of Brown University, for the note, page 757, ex- 
plaining the term "Promoter," page 227; to Professor John 
M. Manly of Brown University, for information and aid in 
the notes to the New Essays, Book III., chap. 2, page 294, 
notes 2, 3, page 295, notes 2, 3; to Professor E. B. Delabarre 
of Brown University, for aid in the note to page 122, lines 
1, 2, infra, pages 739-740; to Professor H. P. Manning of 
Brown University, for aid in the note on the " perles " of 
De Sluse, page 768; to Rev. R. H. Ferguson, for aid in the 



TRANSLATOR'S PREFACE 



same note, and in the revision of a portion of the Appendix; 
to Mr. Frank E. Thompson, A.M., Head-master of the Rogers 
High School, Newport, R. I., for aid in connection with a 
part of the subject-matter of the Dynamical Pieces in the Ap- 
pendix; to Professor Benjamin 0. True of Rochester Theo- 
logical Seminary, for information and verification of references 
in connection with the notes to the New Essays, Book IV., 
chap. 19, page 599, note 2, 601, note 1, 602, note 1; to Pro- 
fessor F. A. March of Lafayette University, for the location 
of the Latin poetical quotation on page 603 ; to Professor Carl 
Schaarschmidt of Bonn University, for consulting books inac- 
cessible in this country, and for information kindly furnished 
by letter, and for his cordial interest in my work, as well as 
for the very valuable notes to his translation of the New 
Essays, without which mine never would have been written 
in their present form; to the various libraries whose resources 
have in one way or another been placed at my disposal, among 
which should be mentioned the Boston Public Library, the 
Boston Athenaeum, the libraries of Andover Theological Semi- 
nary, Newton Theological Institution, Rochester Theological 
Seminary, Brown University, Harvard University, Yale 
University through Professor Duncan, the Library of the 
Surgeon General's Office, Washington, D.C., and the Red- 
wood Library, Newport, R.I.; to the libraries particularly 
of Newton Theological Institution, Brown University, and 
Harvard University, for the long-continued loan of needed 
books ; to Professor Charles R. Brown of Newton Theological 
Institution for information and the verification of references; 
to my friend and former pupil Mr. Alfred R. Wightman, of 
the Morgan Park Academy of the University of Chicago, for 
the verification of references and aid in the revision of a 
portion of the Appendix; to Mr. Thomas J. Kiernan of the 
Harvard University Library, for special favors in the consul- 
tation of the library, for the loan of books from the same, 
and for information cordially furnished by mail; to Benjamin 
Rand, Ph.D., of the Department of Philosophy at Harvard 
University, for frequent consultation of authorities, verifica- 
tion of references and information furnished; to my friend 
Mr. Richard Bliss, Librarian of the Redwood Library, with- 
out whose competent criticism and constant advice and aid, 



TRANSLATOR'S PREFACE 



added to his comprehensive and accurate knowledge in many 
fields, and especially in bibliography, my notes would have 
been far less full and accurate than, I trust, they now are; 
and last but not least, to my wife for literary criticism in the 
revision of the translation and notes, and aid in the laborious 
task of proof-reading. Had I always accepted and adopted 
her criticism and that of Mr. Bliss, my work would doubtless 
rank higher as a piece of literature than is now possible. 

My thanks are also due and most heartily tendered to 
my publishers, Messrs. Macmillan & Co., for their uniform 
courtesy and long-suffering patience in the repeated but un- 
avoidable delays which have characterized the appearance 
of this book; and to J. S. Cushing & Co., of the Norwood 
Press, for the excellence of their work, and the pains they 
have taken to secure the greatest possible accuracy in the 
same, and for their uniform courtesy and long-suffering 
patience amid the vexatious delays unavoidably incident to 
the preparation of the notes and the correction of the proof. 

In editing the work of a thinker and writer so comprehen- 
sive as Leibnitz, it is impossible to escape all errors of fact or 
judgment. I have done the best I could in the circumstances 
in which I have had to work, away from large libraries and 
from the advice and criticism of fellow-students in the same 
lines. Competent and truth-loving criticism, and the correc- 
tion of any and all real errors will be thankfully received. 

With one sentence from Leibnitz's letter to Coste, June 16, 
1707, as significant of his character and illustrative of his 
spirit, more truth-loving than polemical, and as beautifully 
expressing the essence of true criticism, I close this Preface : 
" Mon but a este plustost d'eclaircir les choses, que cle refuter 
les sentimens d'autruy," which, being interpreted, is: "My 
purpose has been to throw light upon things rather than to 
refute the opinions of another." 

Alfred G. Langley. 

Newport, R.I., April 11, 1896. 



LEIBNITZ'S CRITIQUE OF LOCKE ON 
HUMAN UNDERSTANDING 



GERHARDT'S INTRODUCTION TO HIS EDITION OE 
LEIBNITZ'S NOUVEAUX ESSAIS 

[From the German'] 

In the first philosophical treatise, Meditaiiones de Gognitione, 
Veritate, et Ideis, 1 which Leibnitz published in the year 1684, he 
had firmly laid the foundations of human knowledge ; he de- 
clared adequate and at the same time intuitive knowledge as 
the most complete. At the end he adds : Quod ad controver- 
siam attinet, utrum omnia videamus in Deo ... an vero 
proprias ideas habeamus, sciendum est, etsi omnia in Deo 
videremus, necesse tamen esse ut habeamus et ideas proprias, 
id est non quasi icunculas quasdam, sed affectiones sive modifi- 
cationes mentis nostra, respondentes ad id ipsum quod in Deo 
perciperemus : utique enim aliis atque aliis cogitationibus sub- 
euntibus aliqua in mente nostra mutatio fit ; rerum vero actu 
a nobis non cogitatarum Ide® sunt in mente nostra, ut figura 
Herculis in rudi marmore. The assumption of these ideas 
slumbering in the mind, these innate ideas (angebornen Ideen; 
ide.es innees), Leibnitz regards as necessary in order to 
understand the nature of the mind. (Habet anima in se 
perceptiones et appetitus, iisque natura ejus continetur, he 
writes to Bierling, Hanoverse 12. Augusti 1711. 2 Et ut 
in corpore intelligimus avriTv-n-iav, et figuram generatim, etsi 
nesciamus, quse sint figuree corporum insensibilium : ita in 
anima intelligimus perceptionem et appetitum, etsi non 
cognoscamus distincte insensibilia ingredientia perceptionum 
confusarum, quibus insensibilia corporum exprimuntur.) 
He could therefore only prove the necessary truths, i.e. 

i C. I. Gerhardt: Die philosophischen Schriften von (I. W. Leibniz. Vol. 
i, pp. 422-426. J. E. Erdmann: G. G. Leibnitii Opera PhilosopMca, pp.78- 
81. Translated by George M. Duncan, The Philosophical Works of Leibnitz, 
pp. 27-32, New Haven: Tuttle, Morehouse, & Taylor, 1890. — Tr. 

2 The letter is found in Gerhardt's ed., Vol. 7, pp. 500-502. — Tr. 

3 



LEIBNITZ'S CRITIQUE OF LOCKE 



those which are known by demonstration, inasmuch as the 
senses indeed teach what happens, but not what necessarily 
happens. Such ideas innate to the mind are, according to 
Leibnitz, the conceptions of substance, identity, the true and 
the good. 

The writing of the man who questioned and rejected these 
fundamental principles of the system of Leibnitz could not 
fail to lay claim to Leibnitz's entire attention. It was John 
Locke (born, 1632, at Wrington, near Bristol ; died, 1704, at 
Oates, in the county of Essex, in the house of Sir Francis 
Masham, whose wife was a daughter of Cud worth), who in his 
celebrated work (" An Essay concerning Human Understand- 
ing " ; in four books, London, 1690 *) sought to discover also the 
origin, the certainty, and the extent of human knowledge, but 
who denied the existence of innate ideas and principles, and 
affirmed that the mind is originally like an unwritten tablet 
(tabula rasa). In the first book of the work named, Locke 
seeks to set forth the view that there are no innate ideas, and 
therefore no innate principles and truths ; that the under- 
standing is by nature like an unwritten sheet of paper. The 
second book contains the proof whence the understanding gets 
its ideas. Since there are no innate concepts and principles, 
the origin of all ideas can be only in experience. Experience, 
however, has a double sphere, that of external and of internal 
perception : the first Locke calls Sensation; the second, Reflec- 
tion. Sensation is the perception of external objects mediated 
through the senses ; reflection, the perception of the activities 
of the soul in relation to the ideas presented through the senses. 
Ideas are partly simple, partly complex. Simple ideas arise 
through the single senses, remoter ideas through more senses, 
as extension, form, motion, rest ; through reflection alone, for 

1 This work was already completed in the year 1687 ; an abstract made by 
Locke himself appeared in the following year, 1688, translated into French in 
Leclerc's " Bibliotheque universelle," T. VIII., pp. 49-142. The contents of 
the work, after it was completely published in the year 1690, was communi- 
cated in much detail by Leclerc in the "Biblioth. Univers.," T. XVII., p. 399 
sq. The new editions, which already in the shortest time followed each other 
in quick succession in the years 1694, 1697, 1699, 1705, prove what a mighty 
impression Locke's work made upon cultivated circles. 1700 appeared Coste's 
French translation of Locke's work : it was enriched by Locke himself with 
improvements and additions. Leibnitz followed this French translation in 
the comx^osition of his Nouveaux Essais. 



ON HUMAN UNDERSTANDING 



example, the idea of thought and will ; through union of sensa- 
tion and reflection, the ideas of power, existence, unity. The 
complex ideas are of three kinds : modes, substances, relations. 
The modes, i.e. the complex concepts, which contain nothing 
existing for itself, are either pure (simple modes), as space, time, 
or mixed (mixed modes), as thought, motion, power. By sub- 
stances Locke understands those combinations of simple ideas 
or groups of ideas, which are conceived upon the hypothesis 
that they correspond to definite, actually existing things, so 
that the substance (substratum) presupposed for and in them 
is considered as the point of union for the rest of the constitu- 
ent parts contained in the group of ideas. Of substance, man 
has no clear conception ; it is, according to Locke, worthless. 
According to him this conception is not limited to single things, 
but he extends it also to the collective ideas of many things ; 
thus an army, a herd of sheep, is just as much a substance as 
a single man or one sheep. Relations arise from the comparison 
of many things with one another, as the conceptions of cause 
and effect, time — and place — relations, identity and diversity. 

Ideas and their combinations are apprehended in language ; 
therefore Locke begins in the third book with an investigation 
upon language, in so far as our knowledge, although relating 
to things, is bound to words, and words are an indispensable 
middle-term between thoughts and things. The extent and the 
certainty of knowledge are on this account conditioned upon 
the constitution and significance of words. In the fourth book 
Locke pronounces the concluding judgment upon the extent 
and the different grades of certainty in human knowledge. 1 

Leibnitz's attention was already turned from his own work to 
that of the English philosopher by the above-mentioned edition 
published by Locke himself in the " Bibliotheque universelle." 
When later Locke's work reached his hands, he threw off, as 
was his custom while he skimmed through the book, some 
remarks ; 2 they follow here under the superscription : " Sur 

1 For the foregoing are of value : Hartenstein, Locke's Lehre von der 
menschlichen Erkenntniss in Verr/leichung mit Leibniz's Eritik derselben. 
Leipzig, 1861. — Ueberweg, Grundrlss der Geschichte der Philosophie, 3 Theil. 
Berlin, 1880. 

2 They came into being after the year 1693, since mention is made in them 
of Locke's Tract upon Education: Thoughts on Education, London, 1693. 
They were first printed in Some Familiar Letters between Mr. Locke and 
Several of his Friends, London, 1708, pp. 196-205. 



LEIBNITZ'S CRITIQUE OF LOCKE 



l'Essay de l'entendement humain de Monsieur Lock." * Leibnitz 
sent it in accord with his pleasant custom to Thomas Burnett, 
with whom he corresponded. 2 Through him they came to the 
knowledge of Locke, who, however, upon vain pretexts, de- 
clined every reply thereto. 3 When Leibnitz received among 
others the communication from Burnett (July 26, 1698), that 
Locke had so far expressed his opinion that he for his part did 
not sufficiently understand Leibnitz's remarks upon his book, 
he resolved upon a remodelling of the same. Two fragments 
of the year 1698 are thereupon at hand ; they are printed here 
for the first time, under the superscription : " Echantillon * de 
Reflexions sur le I. Livre de l'Essay de l'Entendement de 
l'homme. — Echantillon de Reflexions sur le II. Livre." Leib- 
nitz again sent them to Burnett ; through whom Locke re- 
ceived them ; but this attempt also on Leibnitz's side remained 
without result, as appears from Burnett's letter to Leibnitz 
October 23, 1700. 

1 On Locke's Essay on Human Understanding. See infra, pp. 13-19. — Tr. 

2 Leibnitz to Thomas Burnett, 7th-17th March, 1696: " I found, also, finally, 
a rough draught which I had had copied formerly, of some remarks I made 
when running through the excellent essay of Locke upon Human Understand- 
ing; I take the liberty of sending you a copy." —Leibnitz to Th. Burnett, 
17th-27th July, 1697 : " What I sent you of my reflections upon the important 
book of Locke is entirely at your disposal, and you can communicate it to 
whomever it seems good to you ; and if it falls into his hands, or those of his 
friends, so much the better; for that will give him an opportunity to instruct 
us and to clear up the matter." 

3 Highly characteristic is that which Burnett communicated to Leibuitz 
upon the 23d of July, 1697: " I must tell you a joke of Locke's the other day, 
on this matter. We began to speak of the controversies of savants with those 
of this country. He said : ' It seems to me we live very peaceably as good 
neighbors of the gentlemen in Germany, for they do not know our books, and 
we do not read theirs, so that the tale (la [? le — Tr.] conte) (? le compte, the 
account) was well adjusted on each side.'" — On the other hand, we find 
a very dissenting judgment of Locke's upon Leibuitz and his remarks in 
his letter to Dr. Molyneux, of April 10, 1697: '"'I must confess to you that 

Mr. L 's great name had raised in me an expectation which the sight of 

his paper did not answer, uor that discourse of his in the 'Acta Eruditorum,' 
which he cpiotes, and I have since read, and had just the same thoughts of 
it, when I read it, as I find you have. From whence I only draw this infer- 
ence, That even great parts will not master any subject without great thinking, 
and even the largest minds have but narrow swallows." — Not less disparaging 
is Locke's judgment upon Leibnitz in the next letter to Molyneux, of May 3, 
1697. — The correspondence between Locke and Molyneux is contained in the 
already quoted book: Some Familiar Letters between Mr. Locke, etc. 

4 Specimen of Reflections on Book I. of the Essay on Human Understand- 
ing. Specimen of Reflections on Book II. See infra, pp. 20-25. —Tr. 



ON HUMAN UNDERSTANDING 



In the year 1700 appeared the French translation of Locke's 
work published by Pierre Coste ; 1 it was prepared according to 
the fourth edition and contained accordingly the additions 
which Locke had made to the previous editions of his book. 
Leibnitz at once took occasion thereof to write a sketch for the 
"Monatliche Auszug 2 aus allerhand neu-herausgegebenen, niitz- 
lichen und artigen Buchern," for the year 1700 (September,, pp. 
611-636) . This follows here under No. III. 3 together with the 
supplement of the following year, 1701. 4 In this sketch Leib- 
nitz discusses two of the weightiest of Locke's additions, filling 
two separate chapters, viz. : chapter 33 of the second book, 
wherein Locke treats of the Association of Ideas, and then 
chapter 19 of the fourth book, in which he discourses of 
Enthusiasm. 

Through the French translation Leibnitz first gained real 
access to Locke's work. 5 He recognized the importance of its 
contents in its fullest extent ; at the same time the extremely 
large circulation and the universal recognition, which ex- 
pressed itself through the editions following each other in 
rapid succession, must have made upon him a deep impression. 
Evidently for these reasons Leibnitz conceived the plan of 

1 Essai Philosophique concernant 1'entendement humain, oil Ton montre, 
quelle est l'entendue cle nos Conuoissances certaines et la maniere dont nous y 
parvenons, traduit de 1' Anglais de Mr. Locke par Mr. Pierre Coste, sur la 
quatrienie edition, revue, corrigee et augnientee par l'Auteur. A Amsterd., 
1700. 4. This first edition of Coste's translation was not accessible to me : I 
have been able to make use of the second : Essai Philosophique concernant, 
etc. Traduit de l'Anglois par M. Coste. Seconde edition, revue, corrigee, et 
augmentee de quelques Additions import-antes de l'Auteur qui n'ont paru 
qu'apres sa mort, et de quelques Remarques du Traducteur. A Amsterd., 
1729. 4. 

2 I.e. " ' Monatliche Auszug' (Monthly Abstract) of the various newly pub- 
lished, profitable, and pleasing books." — Tr. 

3 See infra, pp. 2G-38. — Tr. 

4 This " Monatliche Auszug " appeared in three annual sets from 1700-1702. 
Guhrauer (Leibnitz's deutsehe Schriften, 2ter Band) has tried to prove in a 
very complete excursus that Leibnitz was the real editor of this Journal . 
Certainly the sketch of Locke's work originated with him. 

5 Leibnitz to Thomas Burnett, 17th-27th July, 1696: "I could wish I had 
the same knowledge of the English language " (as of the French); "but, not 
having had the occasion for it, all I can do is to understand passably the books 
written in this language. And at the age at which I have arrived, I doubt if 
I could ever make myself better acquainted with it." — Leibnitz to Coste, of 
June 16, 1701: "I have followed your French version, because I thought it 
proper to write my remarks in French, since nowadays this kind of investiga- 
tion is but little in fashion in the Latin Quarter." 



LEIBNITZ'S CRITIQUE OE LOCKE 



answering Locke's work with a more extensive writing. It 
grew out of the often hastily-thrown-off remarks which, he 
occasionally put on paper in the years following that of 1700, 
in which he was not permitted to undertake any continuous 
work. 1 In order to obliterate the traces of this method of 
'work, Leibnitz considered it advisable, before he published it, 
to submit his book, as to composition and style, to the judg- 
ment of a native Frenchman. This revision was protracted 
until the year 1705, as appears from a writing which has no 
signature. 2 Another delay occurred by reason of the fact that 
Leibnitz in the following year, 1706, entered into correspond- 
ence with Pierre Coste, the translator of Locke's work ; Coste 
told him (April 20, 1707) that the translation of Locke itself 
would be examined and furnished with important improve- 
ments; he would urgently advise him (Leibnitz) to put off 
the publication of his work until he obtained a knowledge of 
these changes of Locke. This further consideration, that he 
learned of the dissenting opinions of Locke in his corre- 
spondence with Molyneux, as also Locke's death, which had 



1 " I have made these remarks in the leisure hours when I was travelling or 
at Herrenhausen, where I could not apply myself to researches which required 
more care " (besoin * in sense of soin ? — Tr.) . l 

2 " The frequent diversions to which I have been exposed have prevented 
me from pushing forward my remarks. Besides, I have been obliged to divide 
my time between the reading of your work and the commissions with which I 
have been entrusted by the Count de Schwerin, of which I must give accoimt 
to him. You will find few remarks upon this paper; but I have taken the 
liberty of changing in the work itself a very large number of places in reference 
to which I did not at all hesitate when I saw that I could do this without dis- 
arranging the rest of the writing. I have not touched what is properly called 
the style ; but the confidence with which you have honored me obliges me to 
say to you here that it greatly needs amendment, and that you seem too much 
to have neglected it. You know, sir, to what excess our French people have 
carried their well- or ill-founded delicacy. Too long periods are distasteful; 
an And (Et) or some other word too of Ijen repeated in the same period offends 
them; unusual constructions embarrass them; a trifle, so to speak, shocks 
them. It is proper, however, to accommodate yourself to their taste if you 
wish to write in their language ; and, in case you should decide to print your 
work, I believe you will do well to retouch it with a little more severity. I 
am certain that you will not be displeased at the freedom with which I speak 
to you, since it comes from a person devoted to your service." — Feb. 2, 
1705. 

1 "W. T. Harris, editor of the "Journal of Speculative Philosophy," suggests that per- 
haps the reading was besogne (work) — instead of besoin. So that the passage read, 
" researches which required more work (or labor)." — Tr. 



ON HUMAN UNDERSTANDING 



already followed in the year 1704, altered Leibnitz's original 
plan. 1 

In order to obtain an easier entrance for his own ideas, and 
at the same time to make his reader familiar with those of 
Locke, Leibnitz had composed his work in the form of a dia- 
logue. Two friends, Philalethes and Theophilus, converse 
together ; the first states the views of Locke, the second joins 
thereto his own (Leibnitz's) remarks. This form of composi- 
tion Leibnitz thought of abandoning. He writes to Thomas 
Burnett, May 26, 1706 : " The death of Locke has taken away 
my desire to publish my remarks upon his works. I prefer 
now to publish my thoughts independently of those of 
another." On the other hand, he remarks, wellnigh it seems 
in the opposite sense, to the same, three years later, May 12, 
1709: "My remarks upon the excellent work of Locke are 
almost finished ; although we are not of the same opinion, I 
do not cease to value it and to find it valuable." 

Leibnitz's work remained, in form at least, unfinished ; a 
magnificent torso, and unpublished. 2 He turned to the compo- 

1 Leibnitz to Coste, June 16, 1707 : " The great merit of Mr. Locke, and the 
general esteem which his work has with so much justice gained, united to 
some intercourse by letters which I have had the pleasure of having with my 
Lady Masham, caused me to employ some weeks in remarks upon this impor- 
tant work, in the hope of conferring upon them with Mr. Locke himself. But 
his death shocked me, and caused my reflections to be behindhand, although 
they are finished. My purpose has been to throw light upon things rather 
than to refute the opinions of another. I shall be delighted, however, sir, to 
receive the additions and corrections of this excellent man, in order to profit 
from them." — Leibnitz to Remond, March 14, 1711: "He (Hugony) has also 
seen my somewhat extended reflections upon Locke's work, which treats of 
Human Understanding. But I dislike to publish refutations of dead authors, 
although they might appear during their lifetime and be communicated to the 
authors themselves. Some minor remarks escaped me, I know not how, and 
were carried to England by a relative of the late Mr. Burnett, bishop of Salis- 
bury. Locke having seen them, spoke of them slightingly in a letter to 
Molyneux, which may be found among some posthumous letters of Locke. I 
learned his opinion of them only from this impression. I am not astonished 
at it : we differed a little too much in principles, and the views I advanced 
seemed to him paradoxical. However, a friend more biassed in my favor and 
less so in favor of Locke informs me that those of my reflections there inserted 
appear to him the best of the collection. I do not adopt this view, not having 
examined the collection." 

2 Over the Preface, which certainly was composed after the completion of 
the entire work, Leibnitz has written as the title of the work : Nouveaux Essais 
sur l' entendement par VAuteur du systeme de VHarmonie preestablie. In the 
Preface itself he leaves out the word " humain." The superscription of the 



10 LEIBNITZ'S CRITIQUE OE LOCKE 

sition of the " Theodicy." For the first time, fifty years after 
his death, it was sent to the press in " CEuvres Philosophiques 
latines et francoises de feu Mr. de Leibnitz. Tirees de ses 
manuscrits qui se conservent dans la bibliotheque E-oyale a 
Hanovre, et publiees par Mr. Rud. Eric. Easpe. Avec une 
Preface de Mr. Kaestner, Professeur en Mathematiques a 
Gottingen. A Amsterdam et a Leipzig, 1765." The present 
impression has been newly compared with the original, so far 
as it is still extant. 1 The corrections in reference to the style 
proposed by the native Frenchman are not taken into consider- 
ation, in order not to obliterate Leibnitz's style of expression ; 
they relate, indeed, only to the first books. 

In the preface to his work, in which Leibnitz has put 
together the points of difference between his system and that 
of Locke, he remarks in the first place that Locke's Essay upon 
Human Understanding is one of the most beautiful and valua- 
ble works of its time ; that he has determined to make some 
remarks upon it, because he himself has considered the same 
subject for a long time, and deemed it a good opportunity to 
create a favorable entrance for his own ideas in this way. 
His own system differs, in truth, from Lo.cke's considerably, in 
so far as Locke's is more closely related to Aristotle, his own, 
on the other hand, to Plato ; Locke's is more universally com- 
prehensible, his own more abstract. Meanwhile, by clothing 
his own remarks in the form of a dialogue between two per- 
sons, one of whom presents Locke's views, the other joins 
thereto his own, he hopes to avoid the dryness belonging to 
abstract remarks ; at the same time the reader is spared the 
labor of comparing the passages from Locke's essay under dis- 
cussion. — The first important point of difference, wherein 
Leibnitz distinguishes himself from Locke, is in the ques- 
tion whether the soul is in itself empty like a tabula rasa, as 
Aristotle had already maintained, and that it receives every- 
thing through sense-perceptions and experience, or whether 

fourth book runs thus : Nouveaux Essays sur V 'entendement ; in the case of 
the three first hooks we find the superscription : Nouveaux Essais sur V en- 
tendement humaine. 

1 In the original, Leibnitz has enclosed the words of Philalethes, who states 
the views of Locke, in [], perhaps as an indication that they are not his own. 
Raspe has omitted them. — Gerhaedt's Note. In this translation Gerhardt's 
use of [] has been strictly followed. — Tit. 



ON HUMAN UNDERSTANDING 



the soul originally has the principles of many conceptions and 
doctrines, as Leibnitz with Plato thinks. Hence arises another 
question, whether all truths depend upon experience, or whether 
there is still another principle. The senses are necessary for 
our actual knowledge, but they give us only examples, i.e. in- 
dividual truths, which are not adequate for grounding the uni- 
versal necessity of a truth. The necessary truths, which are 
found in pure mathematics, appear to rest upon other princi- 
ples, whose proof depends not upon experience and the testi- 
mony of the senses, — a point to be well considered. Logic, 
metaphysics, ethics, are full of such truths, which can arise 
only from such principles as are called innate. It is neverthe- 
less possible, continues Leibnitz, that my opponent is not 
wholly remote from my view. For after he has rejected 
innate ideas in the first book of his essay, he begins the second 
book with the statement that the ideas which have not their 
origin in sensation arise through reflection. What, however, 
is reflection but a regard for what is in us and born in us ? 
Such are the ideas of being, unity, substance, etc. If, thinks 
Leibnitz, an understanding with his opponent might easily, 
perhaps, be re-established in reference to the above, yet it 
might create more difficulty in reference to the affirmation 
that the soul does not always think, just as bodies do not - 
always have motion. To this Leibnitz opposes the statement 
that bodies are always in motion and that a substance cannot 
exist without activity ; there are in the soul a multitude of 
impressions too small to be separately distinguished, but which, 
however, united produce an activity, although simply inarticu- 
late, like the noise of the waves. These little perceptions are 
of greater significance than we think. By means of these in- 
sensible perceptions the pre-established harmony between the 
soul and the body is explained. In the same manner they are 
of great importance for Physics, for thereupon rests the law 
of continuity. These minute insensible perceptions are also 
the reason why there are not two perfectly similar souls or 
things of the same kind. 

Another point of difference between Leibnitz and Locke is 
in reference to the conception of the nature of Matter. Locke 
considered the smallest particles of matter to be rigid bodies, 
and therefore assumed that space is empty, else were any mo- 



LEIBNITZ'S CRITIQUE OF LOCKE 



tion impossible. Leibnitz, on the other hand, supposes space 
to be filled with a fluid matter which is divisible to infinity ; 
he calls especial attention to the fact that Locke, who at first 
professed the gravitation theory of Newton constantly contested 
by Leibnitz, viz. : that bodies work upon each other from any 
distance whatever without touching, at a later period freed 
himself from this assumption of Newton. 

In discussing the concepts of space, time, and number, Locke 
had remarked that only with these concepts may that of infinity 
be united. Leibnitz agrees with him in this, that there is 
neither an infinite space, nor an infinite time, nor an infinite 
number, that in general the infinite is not given in that which 
is put together out of parts. But the true infinite, Leibnitz 
adds, is in the Absolute, which is without parts. From this 
proceeds the concept of the finite through limitation. 

In the beginning of the third book Locke had undertaken 
a discussion of language as the expression of the forms of 
knowledge. He had made thereby a distinction between nom- 
inal and real being. Leibnitz rejects this distinction as a 
perplexing innovation. Things, Leibnitz affirms, have only 
one essence, but different definitions of them, nominal and real 
definitions, are possible. 

The contents of the fourth book, in which is treated the 
knowledge of the truth, gives Leibnitz no occasion to raise an 
important point of controversy. In reference to the axioms, 
whose indispensableness to scientific investigations Leibnitz 
affirms, Locke contests, the former enters into a more protracted 
explanation. In like manner he turns against Locke's notion 
that the use of Logic is rather unfruitful. 



ON LOCKE'S ESSAY ON HUMAN UNDERSTANDING, 1 

1696 

[From the French] 

I find so many marks of unusual penetration in what 
Mr. Locke has given us on the Human Understanding and 
on Education, and I consider the matter so important, that 
I have thought I should not employ the time to no purpose 
which I should give to such profitable reading ; so much the 
more as I have myself meditated deeply upon the subject 
of the foundations of our knowledge. This is my reason for 
putting upon this sheet some of the reflections which have 
occurred to me while reading his Essay on the Understanding. 

Of all researches, there is none of greater importance, since 
it is the key to all others. The first book considers chiefly 
the principles said to be born with us. Mr. Locke does not 
admit them, any more than he admits innate ideas. He has 
doubtless had good reasons for opposing himself on this point 
to ordinary prejudices, for the name of ideas and principles 
is greatly abused. Common philosophers manufacture for 
themselves principles according to their fancy ; and the 
Cartesians, who profess greater accuracy, do not cease to 
intrench themselves behind so-called ideas of extension, of 
matter, and of the soul, desiring to avoid thereby the necessity 
of proving what they advance, on the pretext that those who 
will meditate on these ideas will discover in them the same 
thing as they ; that is to say, that those who will accustom them- 
selves to their jargon and mode of thought will have the 
same prepossessions, which is very true. 

My view, then, is that nothing should be taken as first 
principles but experiences and the axiom of identity or (what 
1 Erdmann, Leibnitii Opera Philosophica, pp. 136-139. — Tit. 



14 LEIBNITZ'S CRITIQUE OF LOCKE [i 

is the same thing) contradiction, which is primitive, since 
otherwise there would be no difference between truth and 
falsehood ; and all investigation would cease at once, if to 
say yes or no were a matter of indifference. We cannot, then, 
prevent ourselves from assuming this principle as soon as we 
wish to reason. All other truths are demonstrable, and I value 
very highly the method of Euclid, who, without stopping at 
what would be supposed to be sufficiently proved by the so- 
called ideas, has demonstrated (for instance) that in a triangle 
one side is always less than the sum of the other two. Yet 
Euclid was right in taking some axioms for granted, not as 
if they were truly primitive and indemonstrable, but because 
he would have come to a standstill if he had wished to reach 
his conclusions only after an exact discussion of principles. 
Thus he judged it proper to content himself with having 
pushed the proofs up to this small number of propositions, 
so that it may be said that if they are true, all that he says 
is also true. He has left to others the task of demonstrating 
further these principles themselves, which besides are already 
justified by experience ; but with this we are not satisfied in 
these matters. This is why Apollonius, Proclus, and others 
have taken the pains to demonstrate some of Euclid's axioms. 
Philosophers should imitate this method of procedure in order 
finally to attain some fixed principles, even though they be 
only provisional, after the way I have just mentioned. 

As for ideas, I have given some explanation of them in a 
brief essay printed in the " Actes des Scavans " 1 of Leipzig for 
November, 1684 (p. 537), which is entitled Meditationes de 
Cognitione, Veritate, et Ideis; 2 and I could have wished that 
Mr. Locke had seen and examined it ; for I am one of the most 
docile of men, and nothing is better suited to advance our 
thought than the considerations and remarks of clever per- 
sons, when they are made with attention and sincerity. I 
shall only say here, that true or real ideas are those whose 

i The "Acta Eruditorum," Lipsiae, 1682-1731.— Tr. 

2 Gerhardt, Vol. 4, pp. 422-426 ; Erdmann, pp. 78-81. Translated in part by 
Sir William Hamilton, Lectures on Logic. Lect. X., t XXX., pp. 127-129, 
Amer. ed. ; and complete by George M. Duncan, The Philosophical Works 
of Leibnitz, pp. 27-32, New Haven: Tuttle, Morehouse, & Taylor, 1890; 
also by Professor Thomas Spencer Baynes, in the Appendix to his edition 
of the Port Royal Logic. — Tr. 



i] ON HUMAN UNDEKSTANDING 15 

execution we are assured is possible.; Jhe others are doubtful, 
or^iiruase^of - proved impossibility) chimerical. Now the 
possibility of ideas is proved as much a priori by demon- 
strations, by making use of the possibility of other more 
simple ideas, as a posteriori by experience ; for what exists 
cannot fail to be possible. But primitive ideas are those 
whose possibility is indemonstrable, and which are in truth 
nothing else than the attributes of God. 

I do not find it absolutely essential for the beginning or for 
the practice of the art of thinking to decide the question 
whether there are ideas and truths born with us ; whether they 
all come to us from without or from ourselves ; we will reason 
correctly provided we observe what I have said above, and 
proceed in an orderly way and without prejudice. The ques- 
tion of the origin of our ideas and of our maxims is not pre- 
liminary in Philosophy, and we must have made great progress 
in order to solve it successfully. I think, however, that I can 
say that our ideas, even those of sensible things, come from 
within our own soul, 1 of which view you can the better judge by 
what I have published 2 upon the nature and connection of sub- 
stances and what is called the union of the soul with the body. 
For I have found that these things had not been well under- 
stood. I am nowise in favor of Aristotle's tabula rasa; and 
there is something substantial in what Plato called reminis- 
cence. There is even something more; for we not only have a 
reminiscence of all our past thoughts, but also a presentiment 
of all our future thoughts. It is true that this is confused, 
and fails to distinguish them, in much the same way as when 
I hear the noise of the sea I hear that of all the particular 
waves which make up the noise as a whole, though without 
discerning one wave from another. Thus it is true in a cer- 
tain sense, as I have explained, that not only our ideas, but 
also our sensations, spring from within our own soul, and that 
the soul is more independent than is thought, although it is 
always true that nothing takes place in it which is not deter- 



1 The French is : " de nostre propre fonds." — Tr. 

2 In the "Journal des Savants," June, 1695. For the piece, cf. Gerhardt, 
Vol. 4, pp. 477 sq. (first sketch 470 sq.) ; and the portion of his introduction 
and notes referring to the same, Vol. 4, pp. 414-417; Erdmann, pp. 124-128; 
cf. also pp. 129-136. For the translation, Appendix, pp. . — Tr. 



16 LEIBNITZ'S CRITIQUE OF LOCKE [i 

mined, and nothing is found in creatures that God does not 
continually create. 

sj In Book II., which conies to the details of ideas, I admit that 
the reasons brought forward by Mr. Locke to prove that the 
soul sometimes exists without thinking of anything, do not ap- 
pear to me convincing, unless he gives the name of thoughts to 
those perceptions only which are sufficiently noticeable to be 
distinguished and retained. I hold that the soul (and even the 
body) is never without action, and that the soul is never with- 
out some perception : even in dreamless sleep we have a con- 
fused and dull sensation of the place where we are ; and of 
other things. But even if experience should not confirm the 
view, I believe that it may be demonstrated. It is much the 
same as we cannot prove absolutely by experience whether 
there is a vacuum in space, and whether there is rest in matter. 
Nevertheless, questions of this kind appear to me, as well as 
to Mr. Locke, to be decided demonstratively. 

I admit the difference which he puts with much reason be- 
tween matter and space ; but as for the vacuum, many clever 
people have believed in it. Mr. Locke is of this number. I 
was nearly persuaded of it myself ; but I gave it up long ago. 
And the incomparable Mr. Huygens, who was also for the 
vacuum and the atoms, began at last to reflect upon my 
reasons, as his letters can testify. The proof of the vacuum 
derived from motion, of which Mr. Locke makes use, assumes 
that body is originally hard, and that it is composed of a cer- 
tain number of inflexible parts. For in this case it would be 
true, whatever finite number of atoms might be taken, that 
motion could not take place without a vacuum. But all the 
parts of matter are divisible and even pliable. 

There are also some other things in this second book which 
arrest my attention : for example, when it is said (chap. 17) 
that infinity should be attributed only to space, time, and num- 
bers. I believe, indeed, with Mr. Locke that, properly speak- 
ing, we may say that there is no space, time, nor number which 
is infinite, but that it is only true that however great * may be 

1 Gerhardt's text seems here, for some reason, to be defective. It reads 
thus : " Mais qu'il est settlement vray que pour grand que luy sans fin," etc. 
Erdmann's seems the more correct, and is therefore followed in the translation. 
It reads thus: "Mais qu'il est seulement vrai que pour grand que soit un 
espace, un terns, ou un nonibre, il y en a toujours un autre plus grand que lui 



i] ON HUMAN UNDERSTANDING 17 



a space, a time, or a number, there is always another greater 
than it without end; and that thus the true infinite is not 
found in a whole composed of parts. It is none the less, how- 
ever, found elsewhere ; namely, in the absolute, which is with- 
out parts, and which has influence over compound things, 
because they result from the limitation of the absolute. The 
positive infinite, then, being nothing else than the absolute, it 
may be said that there is in this sense a positive idea of the 
infinite, and that it is anterior to that of the finite. For the 
rest, in rejecting a composite infinite, we do not deny the 
demonstrations of the geometers de Seriebus infinitis, and par- 
ticularly what the excellent Mr. Newton has given us, not to 
mention my own contributions to the subject. 

As for what is said (chap. 30) de ideis adcequatis, it is 
allowable to give to the terms the signification which one finds 
pertinent. Yet without, finding fault with Mr. Locke's mean- 
ing, I put degrees in ideas, according to which I call those 
adequate in which there is nothing more to explain, much the 
same as in numbers. Now all ideas of sense-qualities, as of 
light, color, heat, not being of this nature, I do not reckon 
them among the adequate. So it is not through themselves, 
nor a priori, but through experience, that we know their reality 
or possibility. 

There are further many good things in Book III. in which 
he treats of words or terms. It is very true that everything 
cannot be defined, and that sense-qualities have no nominal 
definition : thus they may be called primitive in this sense ; but 
they can none the less receive a real definition. I have shown 
the difference between these two kinds of definition in the 
meditation 1 cited above. The nominal definition explains the 
name by the marks of the thing ; but the real definition makes 
known a priori the possibility of the thing defined. For the 
rest, I strongly commend Mr. Locke's doctrine of the demon- 
strability of moral truths. 

The fourth or last book, which treats of the knowledge of 
truth, shows the use of what has just been said. I find in it, 
as well as in the preceding books, an infinite number of beauti- 

sans fin." p. 138 a. Cf. also Leibniz's Neio Essays concerning the Human 
Understanding . — A Critical Exposition, by John Dewey, Ph.D. pp. 190. 
Chicago: S. C. GriggsPfe Co., 1888. — Tr. 

1 I.e. Meditationes de Cognitione, Veritate, et Ideis. — Tr. 
C 



18 LEIBNITZ'S CRITIQUE OF LOCKE [i 

ful reflections. To make suitable remarks upon them would 
be to make a book as large as the work itself. It seems to me 
that the axioms receive therein a little less consideration than 
they deserve. The apparent reason for this is that, excepting 
those of the mathematicians, we ordinarily find none which 
are important and solid: I have tried to remedy this defect. I 
do not despise identical propositions, and I have found that 
they are of great use even in analysis. It is very true that 
we know our own existence by an immediate intuition, and 
that of God by demonstration; and that a mass of matter, 
whose parts are without perception, cannot make a thinking 
whole. I do not despise the argument invented some centuries 
ago by Anselm, archbishop of Canterbury, which proves that 
the perfect being must exist; although I find that the argu- 
ment lacks something, because it assumes that the perfect 
being is possible. For if this single point were proved in addi- 
tion, the whole demonstration would be complete. 

As for the knowledge of other things, it is very well said, 
that experience alone does not suffice for a sufficient advance 
in Physics. A penetrating mind will draw more conclusions 
from some quite ordinary experiences, than another could draw 
from the most choice ; besides, there is an art of experimenting 
upon and, so to speak, questioning nature. Yet it is always 
true that we can make progress in the details of Physics only 
in proportion as we have experience. 

Our author shares with many able men the opinion that the 
forms of logic are of little use. I should be quite of another 
opinion, and I have often found that the paralogisms, even of 
mathematics, are the faults of form. Mr. Huygens has made 
the same observation. Much might be said upon this point, 
and many excellent things are despised because the use of 
which they are capable is not made of them. We are inclined 
to despise what we have learned in the schools. It is true we 
learn there many useless things ; but it is good to exercise 
the function della Orusca, 1 i.e. to separate the good from the 
bad. 



1 "La Crusca, a celebrated academy of Florence, founded in 1582, for the 
purpose of maintaining the purity of the Italian language, that is to say, of 
separating the bran (crusca) from the flour : hence the name." Duncan's note. 
Philos. Works of Leibnitz, p. 378. 



i J ON HUMAN UNDERSTANDING 19 

Mr. Locke can do this as well as any one whatsoever ; and in 
addition he gives us important thoughts of his own invention ; 
his penetration and fairness appear everywhere. 1 He is not 
only an assayer, but he is also a transmuter by the increase of 
good metal he gives. Should he continue to present it to the 
public, we should be greatly indebted to him. 

1 Erdmann omits this clause. — Tr. 



II 



SPECIMEN OF THOUGHTS UPON THE FIEST BOOK 
OF THE ESSAY ON HUMAN UNDERSTANDING 

[From the French'] 

In order to prove that there are no ideas born with us, the 
excellent author of the Essay on Human Understanding ad- 
duces experience, which shows us that we need external occa- 
sions in order to think of these ideas. I agree with him, but 
it does not seem to me that it follows that the occasions which 
cause us to see them, cause them to spring into being. And 
this experience cannot determine whether it is through immis- 
sion of a species or by impression of outlines upon an empty 
tablet, or whether it is by the development of what is already 
in us that we perceive ourselves. It is not extraordinary that 
there be somewhat in our mind of which we are not always 
conscious. Reminiscence shows us that we often have diffi- 
culty in remembering what we know, and in seizing what is 
already in the enclosure and possession of our understanding. 
This proving to be the truth in acquired knowledge, nothing 
prevents its being also true in the case of that which is innate. 
And, indeed, there is still more difficulty in perceiving this 
last, since it has not yet been modified and detailed by ex- 
perience, as is the acquired, of which often the circumstances 
remind us. 

The author undertakes to show in particular that impossibil- 
ity and identity, whole and part, etc., are not innate ideas. But 
I do not understand the force of the proofs he brings. I ad- 
mit that it is difficult to make men perceive distinctly these 
metaphysical notions, for abstraction and thought cost them 
effort. But one may have in himself that which he has diffi- 
culty in distinguishing there. Something else, however, than 
20 



ON HUMAN UNDERSTANDING 



the idea of identity is necessary to answer the question, which 
is here proposed, viz. : Whether Euphorbus and Pythagoras 
and the cock, 1 in which the soul of Pythagoras dwelt for some 
time, were always the same individual, and it does not at all 
follow that those who cannot solve this question have no idea 
of identity. What is clearer than the ideas of geometry? 
Yet there are some questions which we have not yet been able 
to decide. But that one which considers the identity of Pytha- 
goras following the story of his metempsychosis is not one of 
the most impenetrable. 

Eegarding the idea of God, he brings forward examples of 
some nations who have had no such knowledge. M. Fabritius, 
a very distinguished theologian of the late Elector Palatine 
Charles Louis, has published the " L'Apologie du genre humain 
contre l'accusation de PAtheisme," in which he replies to such 
passages as are here cited. But I do not enter into this dis- 
cussion. Suppose there are men, and even peoples, who have 
never thought of God ; we may say that this fact proves only 
that there has not been an occasion sufficient to awaken in 
them the idea of the supreme substance. 

Before passing to the complex principles or primitive truths, 
I will say that I agree that the knowledge, or better, the actual 
consideration (envisagement), of ideas and truths is not innate, 
and that it is not necessary that we have distinctly known 
them in a former state of being, according to Plato's doctrine_ 
of reminiscence. But the idea being taken for the immediate 
internal object of a notion, or of what the logicians call an 
incomplex term, there is nothing to prevent its always being 
in us, for these objects can subsist Avhen they are not per- 
ceived. Ideas and truths may, furthermore, be divided into 
primitive and derivative : the knowledge of the primitives 
does not need to be formed ; they must be distinguished only ; 
that of the derivative is formed by the understanding and by 
the reason upon occasion. However, we may say in one sense, 
that the internal objects of this knowledge, that is to say, the 
ideas and truths themselves, primitive as well as derivative, 
are all in us, since all the derivative ideas and all the truths 
deduced from them result from the relations of primitive ideas 
which are in us. But usage makes it customary to call innate 

i Cf. Locke, Philos. Works (Bohn's eel.), Vol. 1, p. 181 sq., and note. — Tr. 



22 LEIBNITZ'S CRITIQUE OF LOCKE [n 

the truths to which credence is given as soon as they are 
heard, and the ideas whose reality (that is to say, the possibility 
of the thing which it represents) is of the number of these 
truths, and needs not to be proved by experience or by reason; 
there is then considerable ambiguity in this question, and it 
suffices at the last to recognize that there is an internal light 
born with us, which comprises all the intelligible ideas and all 
the necessary truths which are only a result of these ideas and 
need not experience in order to be proved. 

To reduce, then, this discussion to something practical, I 
believe that the true end one should have is the determination 
of the grounds of truths and their origin. I admit that con- 
tingent truths, or truths of fact, come to us by observation 
and experience ; but I hold that necessary derivative truths de- 
pend upon demonstration, i.e. upon definitions or ideas, united 
with the primitive truths. And the primitive truths (such as 
the principle of contradiction) do not come at all from the 
senses or from experience, and cannot be perfectly proved, but 
from the natural internal light, and this is what I mean in 
saying that they are innate. The geometers also have very 
well understood this. They could prove passably their proposi- 
tions (at least, the most important of them) by experience, and 
I do not doubt that the ancient Egyptian and the Chinese 
had such an experimental geometry. But the true geometers, 
above all, the Greeks, have desired to show the force of rea- 
son, and the excellence of science, by showing that they can 
in these matters foresee everything, by the internal light in 
advance of experience. It must also be admitted that experi- 
ence never assures us of a perfect universality, and still less 
of necessity. Some of the ancients laughed at Euclid because 
he proved what a fool even is not ignorant of (as they say), viz. : 
that in a triangle two sides together are greater than the third. 
But those who know what genuine analysis is, are much 
obliged to Euclid for his proof. And it is much that the 
Greeks, if less exact in other things, have been so much so in 
geometry. I attribute it to providence ; and I believe without 
that we should hardly know what demonstration is. I also 
believe that it is principally in that respect that we are thus 
far superior to the Chinese. 

But it is needful further to look a little at what our clever 



n] ON HUMAN UNDERSTANDING 23 

and celebrated author says in chapters 2 and 3, to sustain his 
point that there are no innate principles. He is opposed to 
the universal consent alleged in their favor, maintaining that 
many races doubt even this famous principle that two contra- 
dictories cannot be true or false at once, and that the greater 
part of the human race ignores it altogether. I admit that 
there are an infinite number of persons who have never made 
a statement of them. I have indeed seen authors who desired 
to refute them, apprehending them, without doubt, wrongly. 
But where shall we find one who does not avail himself of 
them in practical life, and who is not offended with a liar who 
contradicts him ? Nevertheless, I do not ground myself wholly 
upon universal consent ; and as for propositions which are ap- 
proved as soon as they are proposed, I admit that it is not at 
all necessary for them to be primitive or proximate to them, 
for they may be very common facts. As for this statement 
which teaches us that one and one make two (which the author 
brings forward as an example), it is not an axiom, but a defini- 
tion. And when he says that sweetness is a different thing 
from bitterness, he states only a fact of primitive experience, 
or of immediate perception. Or better, we have only to say 
that the perception of what is understood by the term sweet- 
ness is different from the perception of that which is under- 
stood by the term bitterness. I do not here distinguish at all 
the practical truths from the speculative ; they are always the 
same. And as we can say that it is one of the most manifest 
truths, that a substance whose knowledge and power are 
infinite should be honored, we can say that it emanates at 
once from the light which is born with us, provided one can 
give his attention to it. 



SPECIMEN OE THOUGHTS UPON THE SECOND 
BOOK 

[From the French] 

It is very true that our perceptions of ideas come either 
from the external senses or from the internal sense, which may 
be called reflection ; but this reflection is not limited to the 



24 LEIBNITZ'S CEITIQUE OF LOCKE [n 

operations alone of the mind, as is stated (chap. 1, § 4) ; it 
reaches even to the mind itself, and it is in the consciousness 
of self that we perceive substance. 

I admit that I am of the opinion of those who believe that 
the soul always thinks, although often its thoughts are too 
confused and too feeble for it to be able distinctly to remember 
them. I believe I have certain proofs of the continual activity 
of the soul, and I believe also that the body can never be 
without motion. The objections raised by the author (Book 
II., chap. 1, §§ 10 to 19) can be easily met by what I have just 
said or am about to say. They are based upon the experience 
of sleep, which is sometimes dreamless ; and in fact there are 
some persons who do not know what it is to dream. How- 
ever, it is not always safe to deny everything that is not per- 
ceived. It is much the same as when there are people who 
deny the corpuscles and insensible motions, and laugh at the 
particles because they cannot be proved. But some one will 
tell me that there are proofs which force us to admit them. 
I reply that there are in like manner proofs which compel us 
to admit perceptions which are not marked enough for us to 
remember them. Experience, furthermore, favors this view ; 
for instance, those who have slept in a cold place notice that 
they have had while sleeping a confused and feeble sensation. 
I know a person who wakes up when the lamp which he 
always keeps lighted at night in his room goes out. But here 
is something more precise, and which shows that if we did 
not always have perceptions, we could never be waked up 
from. sleep. Let a man who is sleeping be called by several 
persons at once, and let it be assumed that the voice of each 
by itself is not loud enough to awake him, but that the noise 
of all these voices together awakes him : let us take one of 
them ; it is very necessary that he be touched by this voice in 
particular, for the parts are in the whole, and if each one by 
itself does nothing at all, the whole will do nothing, either. 
Yet he would have continued to sleep, if the voice had been a 
single one, and that, too, without remembering that he had been 
called. Thus there are some perceptions too feeble to be 
noticed, although they are always retained, but among an infi- 
nite number of other small perceptions which we have con- 
tinually. For neither motions nor perceptions are ever lost; 



ii] ON HUMAN UNDEKSTANDING 25 

both continue always, only becoming indistinguishable through 
composition with many others. One might reply to this 
reasoning, that each voice by itself effectively touches the 
body, but that a certain quantity of it is needed in order that 
the motion of the body may reach the soul. I reply, that the 
least impression reaches the entire body, and consequently to 
that part whose motions correspond to the actions of the soul. 
And accordingly no principle of limitation can be found, how- 
ever necessary a certain quantity may be. I do not wish to 
insist upon the interest that the immortality of the soul has 
in this doctrine. For if the soul is passive, it is also without 
life, and it seems that it can be immortal only by grace and by 
miracle — a view which there is reason to disapprove. I admit, 
however, that our interest is not the measure of truth, and I 
do not wish to mix here theological reasons with those of 
philosophy. 



Ill 

[From the German'] 

Essai Pliilosophique coucernant l'Entendement humain, ou Ton montre, 
quelle est l'entendue de nos connoissances certaines et la maniere dont nous y 
parvenons, traduit de l'Anglois de Mr. Locke par Mr. Pierre Coste, sur la 
quatrieme edition, revue, corrigee et augmentee par l'Auteur. A Amstei-d. 
1700 in 4to. 

Philosophischer Versuch, betreffend den Menschlichen Verstand, alwo 
gewiesen wird, wie weit sich unsre gewisse Erkaiidtniissen erstrecken, unci 
anJ wass Weise wir darzu gelangen ; ausz den Engliscken iibersetzet von Hrn. 
Peter Coste nach der vierten vom Autor selbst iibersehenen, verbesserten mid 
vermehrten Edition. 5. Alpb. 12. Bog. 

It j is unnecessary for us to give a complete abstract of this 
notable book, after the author himself has relieved us of this 
task, since in the year 1688 he prepared such an abstract for 
Mr. Clerc for insertion in his " Bibliotheque universelle," 2 
T. VIII., p. 49 sqq., before he gave it to the press. In the year 
1690 it appeared first in London in folio, and Mr. Clerc again 
published lengthy excerpts in the said " Bibliotheque univer- 
sale," T. XVII., p. 399. Soon afterwards a new English edition 
appeared, enlarged with many pieces, and in particular with 
an entire chapter 3 on Identity and Diversity, which he treats 
in an exceedingly clear and excellent manner. 

In the second edition mentioned, Locke acknowledges that 
he erred in the first edition when he assumed, in accordance 
with the common view, that what brings the will to any change 
of action in the course of arbitrary actions is the assurance of 
a much greater good. For when he considered the matter 
more carefully, he found that a present unrest which consists 
in desire or is constantly accompanied by the same, places its 
limits upon the will. For the reasons for this view, see Book 

i From the " Monatliche Auszug," Sept. 1700, pp. 611-636. — Tr. 

2 " Bibliotheque universelle et historique," Amsterdam, 1686-1693. — Tr. 

3 In the present edition this chapter is 27 in the second book. — Gerhardt's 
note. 

26 



in] ON HUMAN UNDERSTANDING 27 

II., chap. 21. He will gladly, however, be informed of a bet- 
ter view. Some time after, a third, and in the year 1699, a 
fourth, edition appeared, in which last edition Locke either 
further explained his previous thoughts by many additions or 
supported them by wholly new grounds. Peter Coste made 
his translation on the basis of this edition, and when Locke 
sent him his manuscript, had worked upon the same for more 
than two years. Locke himself considered this translation a 
good one and presented his thanks accordingly, so that con- 
sequently it must be the more welcome by a great deal to us. 

To enumerate all the new additions would take too long; 
hence we will content ourselves with the mention of the two 
most important, which make two separate chapters, of which 
the first is Book II., chap. 33, and treats of the Association of 
Ideas. 

Locke says there is almost no one who does not find 
something in the opinions, conclusions, and actions of other 
people which seems to him fantastic and extravagant, and is so 
in fact. Every one may have eyes keen-sighted enough to 
mark the least fault of this kind in the case of another, if 
only it may be distinguished from his own, and he himself may 
have sufficient understanding to condemn the same, although 
he also may have in his own opinions and his own conduct the 
greatest errors of which he might be aware, and of which, 
where not impossible, he may yet with difficulty be convinced. 

This arises, he continues, not merely from self-love, although 
this passion has often a great part therein. For one daily sees 
such people lying sick with the same disease, who are otherwise 
skilful and whole enough to make nothing of their own merits. 

This defect of reason is customarily ascribed to education 
and to the force of prejudice, and this, according to the common 
opinion, not without cause, but according to Locke's statement, 
this explanation reaches not to the root of the disease, and does 
not show completely its origin and peculiarity. 

He himself explains it as follows : Some of our ideas [his 
own words] have among themselves an exact correspondence 
and connection. The obligation and highest perfection of our 
reason consists in the fact that it reveals such ideas and holds 
them together in the selfsame unity and correspondence as 
that which is grounded in their particular nature. There is 



28 LEIBNITZ'S CRITIQUE OF LOCKE [in 

besides this another bond of ideas which depends upon chance 
or custom, so that the ideas which naturally are wholly unre- 
lated become so exactly united in the minds (esprit 1 ) of some 
men, that they can with difficulty be separated from one 
another. They accompany one another constantly, and one can 
no sooner present itself to the understanding (intellectui) 
than the others or, indeed, more of them, so united are they, 
appear also, nor can they at all be separated from one another. 

This association of ideas, which the mind makes in itself 
either voluntarily or by chance, is the sole source of the defect 
of which we now speak. And as this strong union of ideas is 
not originally caused by nature, it is for this reason wholly dif- 
ferent in different persons, viz. : according to their different 
inclinations, education, and self-interests. 

That there are such associations of ideas, which custom 
begets in the minds of most men, no one, according to Locke's 
statement, can doubt, who with much earnestness considers 
himself and other people. And to this cause can perhaps with 
convenience and reason be ascribed the greater part of those 
sympathies and antipathies which one finds among men, and 
which work as strongly and produce as regular effects^ as if 
they were natural, which fact then makes them to be called so, 
although at first view they had no other origin than the chance 
connection of two ideas, which the strength of a first impres- 
sion, or of an excessively great compliance, so firmly united, 
that they always thereafter remain together in the mind of 
the man, as though only a single idea. Locke, however, in no 
respect denies that there are wholly natural antipathies which 
depend upon our original constitution and are born with us. 
He believes, however, that with proper consideration man 
would recognize the most of those which have been regarded 
as natural, as in the beginning caused by impressions which 
were not heeded, whether they were suggested sufficiently 
early or through a ridiculous fancy. Locke notices incidentally 
the difference which may be made between natural and ac- 
quired antipathies, so that those who have children or who 

1 This word I have voluntarily retained here and for the most part in what 
follows, because it cannot be expressed quite clearly in German. — Leibnitz's 
note, Gerhardt, p. 27. 

Perhaps we should retain the word " esprit " in English. — Tr. 



in] ON HUMAN UNDERSTANDING 29 

must educate them, may see how much heed they should take 
of this principle, and with what care this disorderly union of 
ideas in the mind of the youth should be prevented. 

He thereupon points out by some examples how such a union 
of ideas, which are not of themselves united, yet depend one 
upon another, is sufficient to impede our moral and natural 
action, yea more, our notions themselves. 

The ideas of goblins or of spirits agree as little with dark- 
ness as with light ; if, however, a foolish maid instils and 
awakens these different ideas in the mind of a child, as though 
they were connected with each other, the child during his entire 
life will perhaps not be able to separate them from each other; 
so that the darkness ever more will seem to him to be accom- 
panied with these horrible ideas. 

If any one has suffered a grievous wrong on account of 
another, he thinks very often of the persons and the deed, and 
while he thus strongly or for a long time thinks thereupon, he 
at the same time glues these two ideas together so firmly, that 
he makes them almost one, as it were, and never remembers the 
person but that the wrong received also enters his head. And 
while he can scarcely distinguish these two things, he has just 
as much aversion for the one as for the other. Thence it 
comes, Locke adds, that hatred arises from slight and worth- 
less reasons, and quarrels are taken up and continued in the 
world. 

One of Locke's friends was wholly cured of madness by a 
certain man through a very painful operation, for which service 
he acknowledged himself under great obligation to him through- 
out his life, as he was so circumstanced that he required from 
no one a greater service during his life. Reason or gratitude 
might suggest to him what they would, yet he could never 
bear the sight of this surgeon. For as the sight of him always 
brought again to mind the idea of the very great pain which 
he had been obliged to endure at his hands, he could not endure 
this idea, so violent were the impressions it produced in his 
mind. 

Many children hold their books, which were the occasion 
hereto, accountable for most of the ill treatment they endured 
at school, and they unite these ideas so well that they regard 
a book with great disgust, and all their life study and books 



30 LEIBNITZ'S CRITIQUE OF LOCKE [in 

cannot win their love, because to them reading, which might 
otherwise have greatly delighted them, became a genuine tor- 
ture. 

An example notable for its singularity is the following which 
an eminent man, who assured him he had himself seen it, re- 
lates to Locke : A young man had learned to dance very prettily 
and perfectly. There chanced to stand, however, in the hall 
where he first learned, an old trunk, the idea of which com- 
bined so imperceptibly with his turns and steps in the dance, 
that although he could dance incomparably well in this hall, 
he could do this only when the old trunk was there ; in other 
places, however, he could not dance at all, unless the old trunk 
itself or one like it stood in its accustomed place. 

The habitus intellectuales which are contracted through such 
association of ideas, are, as Locke further informs us, just as 
strong and numerous, even though very little heeded. Sup- 
posing the ideas of being and matter were very strongly united, 
either by education or by an excessively great application to 
these two ideas, according as they are combined in the mind, 
what notions and reasonings would they not produce concern- 
ing different spirits ? If a custom accepted from childhood 
up had united a form or figure with the idea of God, into what 
absurdities would such a thought in the contemplation of deity 
not plunge us ? We shall no doubt find, Locke adds, that it 
is nothing else than similar ill-grounded and unnatural combi- 
nations of ideas, which break the path for the many conflicting 
sects in philosophy and religion ; for it is not to be supposed 
that each member of those different sects is willingly deceived, 
and against his better knowledge and conscience rejects the 
truth demonstrated to him by clear evidence. It is indeed 
certain that sometimes interest assists greatly in this sort of 
thing, yet no one could affirm that it could captivate and lead 
astray whole societies, so that they all, none excepted, should 
affirm plain and deliberate falsehoods. For it must be that 
some at least do what others pretend to do, viz. : seek truth 
sincerely. 

Therefore there must be something which blinds their un- 
derstanding and hinders them from recognizing the falsehood 
of what they consider as pure and refined truth. If now we 
investigate accurately what takes reason prisoner and darkens 



ni] ON HUMAN UNDEESTANDING 31 

the understanding of otherwise sincere people, we find that it 
is simply and solely some free ideas, which, properly speaking, 
really have no bond among themselves, but which, by educa- 
tion, custom, and uninterrupted action on their part, are so 
united in the mind that they can no more be separated and 
distinguished from one another than a single idea. Thence it 
comes, Locke continues, that often the crudest things are 
taken for worthy opinions, absurdities for demonstrations, and 
intolerable and absurd results for strong and fluent reason- 
ings. 

The other chapter we promised to present, treats of Enthu- 
siasm, and is the 19th in the 4th book. Locke's thoughts 
thereupon are as follows : — 

Whoever will earnestly seek for truth must first before all 
things acquire a love for it. Whoever does not love the truth, 
to him we must necessarily attribute the opposite. Hence we 
can rightly say, that among those who pretend to seek it, 
there are very few who really love it. We may recognize a 
genuine seeker of the truth, since he does not assume for a 
statement any greater certainty than the proofs upon which 
he grounds it warrant. Whoever steps beyond this limit lays 
hold of the truth not out of love for it, but from another indi- 
rect purpose. For while the unquestionable clearness of a 
statement truly consists in the evidence for it (excepting 
those which are sufficiently clear of themselves), yet it is 
plain that so far as space is given to assent beyond the unques- 
tionable clearness of a proposition, the remaining portion of 
the assurance is not drawn from love for the truth, but from 
another passion. For as it is impossible that love for the 
truth can bring any one to give to any proposition an assent 
greater than that certified by the truth itself, just so is it also 
impossible that any one out of love for the truth can assent to 
a statement in view of evidence of such a character that from 
it he cannot see whether the statement is true ; which would 
be actually equivalent to the assumption that the proposition 
is a truth because possibly, or, indeed, probably, it seems not 
to accord with the truth. 

Locke adds, it follows indisputably from this evil disposi- 
tion of the mind, that men assume the authority to dictate 
their own opinions to others. For how should one who has 



32 LEIBNITZ'S CRITIQUE OF LOCKE [in 

imposed on his own belief, not be willing also to impose on 
the belief of others ? How is it to be expected that one will 
use valid arguments and proofs in dealing with others, who is 
not accustomed to use them in dealing with himself, who does 
violence to his own powers, who tyrannizes over his own mind, 
and misuses the advantage which truth alone has, viz. : that it 
assents to nothing but what is indisputably true ? 

After Locke has laid this foundation, he proceeds to the in- 
vestigation of Enthusiasm, to which some people ascribe as 
much power as to faith and reason, and would establish revela- 
tion without the aid of reason, whereby, however, they would 
at once destroy both reason and revelation, and without any 
reason erect in their place the fancies forged in their own 
brain, which they choose as the plumb-line of their opinions 
and conduct. Reason is nothing else than a natural revela- 
tion, whereby God bestows upon men that portion of truth 
which he has poured into the capacity of their natural powers. 
Eevelation is natural reason, enlarged by a new set of discov- 
eries flowing immediately from God, the ground (raisoii) of 
which is the truth by testimony and proof they offer that 
these discoveries actually come from God. 1 Whoever, there- 
fore, destroys reason to make room for revelation, extin- 
guishes both these lights at the same time. As, however, men 
find that an immediate revelation is a much easier means of 
strengthening their opinions and of directing their conduct 
than the labor of arranging all according to strict reasoning, 
which is usually irksome, prejudiced, and for the most part 
without successful progress ; so it is not to be wondered at 
that they often pretend revelations and persuade themselves 
that God directs them in particular as regards their actions 
and opinions, and especially in those things which they cannot 
justify by the principles of reason. ' If their minds are once 
possessed with this thought, the most absurd opinions which 
are firmly impressed upon their fancy, must seem to be illu- 
minations coming from the Spirit of God and having divine 
authority. Every extraordinary thing to which they are led 
by a strong impulse, they consider as certainly a divine call 

1 On this whole discussion, cf. an article by the translator entitled "Reve- 
lation, Inspiration and Authority," in "The Andover Review," April 1891. 
— Tr. 



m] ON HUMAN UNDERSTANDING 33 

which they must follow, and as a command from on high in 
whose execution it is impossible to err. 

This is, properly speaking, what is meant by Enthusiasm, 
which is not adjusted to reason nor to divine revelation, but 
springs forth only from the imagination of a heated and con- 
ceited spirit, and which, as soon as it has taken a little root, 
plays much more strongly upon the opinion and actions of 
men than reason or revelation separately or together. 

Although now the extravagant actions and opinions, wherein 
enthusiasm has involved men, should spur them on to be more 
on their guard and to avoid the false principia, which lead 
astray both their belief and their conduct; yet through its 
love for the extraordinary, through its ease and illumined by 
its glory, and through its extraordinary paths to knowledge it 
has come to pass that the laziness, ignorance, and vanity of 
many are so tickled, and they are brought to such a point, that 
after they are captivated by such ways of an immediate reve- 
lation, of an illumination without search, of a certainty with- 
out proof and investigation, it is very difficult to bring them 
out of it again. 

They are transported beyond reason, and reason in their 
case perishes. They see a light infused into their understand- 
ing and can no longer be deceived. This light visibly appears 
as the clearest sunbeam and requires no other proof than its 
own clearness. They feel, according to their statements, the 
hand of God moving them within ; they feel the impulses of 
the Spirit, and cannot be mistaken in their feeling. Thus 
they persuade themselves that reason has nothing to do with 
what they see and feel in themselves. The things which they 
clearly experience are beyond all doubt, and need no proof; 
and so of all the rest of their strange talk. They are sure of 
these things because they are sure of them, and their opinions 
are correct because they are firmly fixed in their mind. For 
this is the upshot of their words when stripped of the meta- 
phors of hearing and feeling in which they are clothed. 

Locke investigates the ground of this inner light and feel- 
ing, upon which these people so firmly base themselves, and 
speaks thus : Is this seeing of the light a perception of the 
truth of a certain particular statement, or perhaps of this, that 
it is a revelation from God ? Is this feeling a perception of 

D 



34 LEIBNITZ'S CRITIQUE OF LOCKE [in 

an inclination, which, comes from a fancy to do something, or 
from the spirit of God, which begets in it this inclination? 
These are two wholly different feelings, which must be care- 
fully distinguished from one another if we would not deceive 
ourselves. I can perceive the truth of a proposition; but I 
cannot thereby know as yet whether it is an immediate revela- 
tion from God. I can perceive the truth of a proposition in 
Euclid without its being or my knowing that it is a revelation. 
I may also know that I did not attain this knowledge through 
natural means, thence may indeed conclude that it is revealed 
to me, but I cannot thereby yet know it is a revelation from 
God; because there may be minds which without a divine 
commission for this work arouse these ideas in me and set 
them in such order in my mind that I may perceive their con- 
nection. So that the knowledge of a proposition, which enters 
my head, I know not how, is thus not an evidence that it 
comes from God. Still less is a firm persuasion that this 
fancy is true, a certain evidence that it comes from God, or 
that it is true. 

We may call such a fancy sight or light, yet it is nothing 
more than belief and confidence. 1 For if the proposition under 
discussion be one which they have imagined, but do not know 
to be true, it cannot be seeing, but believing. One may also 
give to such fancy any name he pleases. What I believe, I 
must put forth as true upon another's testimony, and must 
know certainly in the case that this testimony is given ; for 
without this my belief would be groundless. I must see 
whether God reveals this to me, or whether I see nothing. 
Thus the issue is, that I know how I am to know that God 
reveals something to me, that this impression in my soul 
occurs through the Holy Spirit, and that consequently I am 
bound to follow it. If I do not know this, my confidence, 
great as it may be, is without the least foundation, and all the 
light with which I perceive myself illumined, is but enthusi- 
asm. For whether the proposition supposed to be revealed, 
be evidently true in itself, or visibly probable, or whether it 
be difficult to vindicate it by the ordinary paths of knowledge, 
this must nevertheless before all things be clearly established 
and proved, that God has revealed this proposition, and that 
1 The German is " Creckilitat unci Confiderttz." — Tk. 



in] ON HUMAN UNDERSTANDING 35 

what I take as a revelation certainly comes of itself into my 
mind, and is no illusion, which some one else has thrust in or 
my own fancy has awakened. Until one has come this far, 
all confidence that this revelation comes from God is a mere 
conjecture, and all this light which dazzles one is nothing but 
an ignis fatuus, which will unceasingly lead us into this circle : 
This is a revelation because I firmly believe it; and I believe it 
because it is a revelation. 

It follows from this that those who imagine that they have 
such revelations of this or that truth must be assured that it 
is God who has revealed it to them. For to say, as they gen- 
erally do, that they know it by the light which it brings with 
it,* which shines and flashes in their souls, and which they 
cannot resist, means only that it is a revelation because 
they believe it certainly is one ; since all the light of which 
they speak is nothing but a strong imagination which is firmly 
fixed in their mind, and yet has not the least ground that it is 
a truth. For they must consider that to assume accepted 
grounds as reasonable and as a proof that it is a truth, is a nec- 
essary acknowledgment that they have no such (grounds). 1 
Because, if they have such, they receive this truth no longer 
as a revelation, but as a truth established upon common 
grounds. And if they believe it to be true, because it is no 
revelation, and if they have no other reason to prove it a 
revelation than simply because they are completely persuaded 
of its truth, without any other ground and only on account of 
this fancy, then they believe it to be a revelation only be- 
cause they strongly believe it to be a revelation. Who does 
not see that if we build upon such grounds, we make our own 
fancy the only rule of our opinions and conduct, and conse- 
quently subject ourselves to the strangest errors and vexa- 
tions. For once for all the strength of our opinions is no 
proof of their correctness. Meanwhile men can approve an 
error as a truth, as may be seen in the case of those zealous 
people who maintain in the sharpest manner two propositions 
contrary to one another. 

In reference to which Locke well says, that if the light, 

1 The text is: "Derm dieses miisseu sie vor raisouable unci von einigem 
Beweise halten, der da zeige, class es eine Warheit sey, genommene Griinde 
annehmen, class sie erkennen raiissen, wiesie dergleicheu nicht kaben." — Tn. 



3G LEIBNITZ'S CRITIQUE OF LOCKE [ni 

which every one thinks he has in himself, and which in this 
case is nothing but the strength of his own opinion, be a proof 
that his thought comes from God, then we must conclude that 
all contrary opinions have the right to pass as divine inspira- 
tions ; and God would be not only the father of light, but also 
of wholly opposite lights, which lead men in ways wholly 
contrary. 

Therefore Locke concludes that he who does not wish to 
fall into a mass of disorderly delusions and errors must first 
test thoroughly this inner light which offers itself as a guide. 
God, he says, does not destroy the man when he makes a 
prophet. He leaves all his faculties in their natural condi- 
tion, so that he may thereby judge whether the inspirations 
which he feels within have sprung from God or not. If God 
will have us acknowledge the truth of a proposition, he permits 
us to see this truth either through the ordinary paths of nat- 
ural reason, or he makes us know that it is a truth which we 
must receive upon his authority, while he convinces us by 
certain marks which reason cannot reject that it comes from 
him. I will not, however, Locke adds, say by this, that we are 
to examine by reason whether a proposition thus revealed to 
us by God may be proved by natural principles, and if not we 
may reject it; but I will say, that we must consult reason and 
by its aid see whether it be a revelation from God or no. 
Lor if reason finds it to be a divine revelation, it declares for 
it as such from that hour on as well as for any other truth, 
and makes it one of its rules, so that it cannot be rejected. 

If this inner light, or a proposition which presents itself in 
our mind as revealed, accords with the principles of reason or 
with the word of God which is an attested revelation, we have 
the warrant of reason for it, and may accept this light as true, 
and direct our faith and walk accordingly. If, however, this 
light has the witness or proof of neither of these rules, we 
cannot consider it as a revelation ; nay more, as a truth. Lor 
if we at the same time believe it to be a revelation, that does 
not, however, make it so ; it may, however, be shown by some 
other mark to be really a revelation. The old prophets, when 
they were to receive revelations from God, had other proof 
than the inner light which assured them that these revelations 
really came from God. They imagined not only that their 



in] ON HUMAN UNDERSTANDING 37 

imaginations came from God, but they had also external signs 
which convinced them that God was the author of their reve- 
lation. And if they were to convince others of the same, they 
received beforehand a special power to set forth the truth of 
the commission given them of Heaven with visible signs. Thus 
Moses saw a burning bush which was yet not consumed and 
heard a voice out of the bush. This was something more than 
an inner feeling of an impulse to free the children of Israel 
from the hands of Pharaoh. Yet, Moses did not believe that 
this was enough to warrant him in going into Egypt with God's 
commission ; until God assured him by still another miracle, of 
the rod changed into a serpent, that such was his real will, and 
granted him the power to work precisely similar wonders in 
the sight of Pharaoh. Precisely similar was it in Gideon's 
case. These and other examples of the old prophets show 
sufficiently that they did not believe that an inner vision or 
their own imagination attested by no other affirmation a suffi- 
cient evidence that their imagination came from God ; although 
the Scripture does not everywhere mention that they always 
asked for or received such proofs. 

These few passages from the clever work of Locke, under 
the guidance of the accurate translator Coste, we have brought 
forward as specimens. Perhaps we shall have further oppor- 
tunity to speak of it, when the Latin translation, with which 
some one 1 is now occupied in England, is published. 



In the " Monatliche Auszug " of the year 1701 is found (pp. 
73-75) the following addition to the foregoing sketch : — 

What Locke says of the connection and accompaniment of 
ideas is not to be despised, and serves often to arouse the emo- 
tions ; as for errors and false judgments, however, they spring 
from other contiguous and peculiar causes, viz.: that one 
assumes false principles, and imagines that he once had proof of 
them in -his mind, within which now a lapse of memory occurs ; 
and then from incorrect conclusions which he produces from 
these principles assumed as known, because he gives not the 
time and labor to investigate all in a formal and orderly way. 

1 Burridge of Dublin. The version appeared in 1701. — Tr. 



38 LEIBNITZ'S CRITIQUE OF LOCKE [in 

Meanwhile it is true that the emotions greatly assist this credu- 
lity concerning principles and carelessness in false deduction ; 
for one believes and easily draws the conclusion he would gladly 
have. It is besides noticeable in this book of Locke's, that in 
his last writings against the Rev. Lord Bishop Stillingneet he 
has changed a large part of his opinions concerning the nature 
of the body contained in this Tentamen or Essay on Human 
Understanding ; while in this Tentamen he held opinions, in 
common with modern philosophers, especially the followers 
of Descartes and Gassendi, that in the body nothing is to be 
met with but size, solidity or impenetrability, and motion or 
change ; now, however, he begins to hold the opinion that there 
is something to be found therein not revealed through these 
qualities. He repudiates, besides, in this essay innate ideas 
and the natural light, but appears not to distinguish suffi- 
ciently the necessary truths arising from possibility, from those 
others whose ground must be assumed from the experience of 
realities, and thus must be drawn from without. 

Thus he accepts the tabula rasa of Aristotle, rather than 
the implanted (ideas) of Plato. It is true that we do not 
come upon thoughts in these most abstract matters, without 
external sensations, but in the case of these necessary truths, 
such sensations serve more as a reminder than as a proof; 
which (proof) must come simply and solely from internal 
grounds, as those do not sufficiently understand who deal little 
in demonstration proper. 



NEW ESSAYS ON THE UNDERSTANDING 

By the Author of the System op Pee-Established 
Harmony 



PREFACE 

The Essay on the Understanding, by a distinguished English- 
man, being one of the most beautiful and esteemed works of 
this period, I have resolved to make some remarks upon it, 
because having sufficiently meditated for a long time upon 
the same subject and upon the greater part of the matters 
therein touched upon, I have thought that it would be a 
favorable opportunity to publish something under the title of 
" New Essays on the Understanding," and to procure a favor- 
able reception to my thoughts, by putting them in so good 
company. I 1 have thought also that I could profit from the 
labor of another not only to lessen my own (since in fact it 
is less difficult to follow the thread of a good author than to 
work wholly independently), but further to add something to 
what he has given us, which is always easier than to start from 
the beginning ; for I think I have cleared up some difficulties 
which he had left in their entirety. Thus his reputation is an 
advantage to me ; having for the rest a disposition to render 
justice, and very far from wishing to diminish the esteem in 
which this work is held, I would increase it, if my approval 
carried any weight. It is true I often differ in my views (from 

1 Gerhardt's text reads as follows: "J'ai cru encor pouvoir profiter dix 
travail d'autruy non seulement pour diminuer le mien (puisqu'en effect il y a 
moins de peine a suivre le fil d'un bon auteur qu'a travailler a nouveaux frais 
en tout), mais encor pour adjouter quelque chose a ce qu'il nous a donne, ce 
qui est tousjours plus facile que de commencer; car je crois d'avoir leve 
quelques difficultes qu'il avoit laisse'es en leur entier. Ainsi sa reputation 
m'est avantaguese ; estant d'ailleurs d'Mimeur a rendre justice et Men loin de 
vouloir diminuer l'estime qu'on a poitr cet ouvrage, je l'accroistrois, si mon 
approbation estoit de quelque poids. II est vray que je suis souvent d'un autre 
avis, mais Men loin de disconvenir du merite des Ecrivains celebres, on leur 
rend temoignage, en faisant connoistre en quoy et pour quoy on s'eloigne de 
leur sentiment, quand on juge necessaire d'empecher que leur autorite' ne 
prevaille a la raison en quelques points de consequence, outre qu'en satisfaisant 
a de si excellens homines, on rend la verite plus recevable, et il faut supposer 
que c'est principalement pour elle qu'ils travaillent." — Tr. 

41 



LEIBNITZ'S CRITIQUE OE LOCKE 



him 1 ), but very far from denying the merit of celebrated 
writers, we bear witness to it, by making known in what and 
why we differ from their views, when we judge it necessary 
to prevent their authority from prevailing over reason on some 
important points ; besides, by satisfying such excellent men, 
we render the truth more acceptable, and it must be supposed 
that it is principally for truth that they labor. 

In fact, although the author of the Essay says a thousand 
beautiful things which I commend, our systems are very dif- 
ferent. His has more relation to Aristotle, mine to Plato, 
although we both differ in many things from the doctrine of 
these two ancient philosophers. He is more popular, and I 
am compelled sometimes to be a little more acroamatic and 
more abstract, which is not an advantage to me, especially 
when writing in a living language. I think, nevertheless, that 
by making two persons speak, one of whom sets forth the 
views drawn from the Essay of this author, and the other 
joins thereto my observations, the parallel will be more to the 
liking of the reader than wholly dry remarks, the reading of 
which would be interrupted at every moment by the necessity 
of recurring to his book in order to understand mine. It will 
nevertheless be well still to compare sometimes our writings, 
and not to judge of his views except by his own work, although 
I have ordinarily preserved its expressions. It is true that the 
constraint, which another's discourse, whose thread must be 
followed, gives in making remarks, has prevented me from 
thinking to secure the charms of which the dialogue is sus- 
cej^tible ; but I hope the matter will make amends for the 
defects of the style. 

Our differences are upon subjects 2 of some importance. The 
question is to know whether the soul in itself is entirely empty 
as the tablets upon which as yet nothing has been written 
(tabula rasa) according to Aristotle, and the author of the 
Essay, and whether all that is traced thereon comes solely 
from the senses and from experience ; or whether the soul con- 
tains originally the principles of many ideas and doctrines 
which external objects merely call up on occasion, as I believe 

1 Erdmann and Jacques read : " que lui," which does not occur in Gerhardt's 
text. — Tr. 

2 Erdmann and Jacques read : " ohjects." — Tb. 



ON HUMAN UNDERSTANDING 



with Plato, and even with the schoolmen, and with all those 
who interpret in this way the passage of St. Paul (Rom. 2 : 15) 
where he states . that the law of God is written in the heart. 
The Stoics call these principles 1 prolepses, i.e. fundamental 
assumptions, or what is taken for granted in advance. The 
Mathematicians call them general notions (kolvoI evvocat). Mod- 
ern philosophers give them other beautiful names, and Julius 
Scaliger in particular named them semina ceternitatis, also 
zopyra, i.e. living fires, luminous flashes, concealed within us, 
but which the encounter of the senses makes appear like the 
sparks which the blow makes spring from the steel. And 
the belief is not without reason, that these glitterings indicate 
something divine and eternal which appears especially in the 
necessary truths. Whence another question arises, whether 
all truths depend upon experience, i.e. upon induction and 
examples, or whether there are some which have still another 
foundation. For if some events can be foreseen prior to any 
proof which may have been made of them, it is manifest 
that we ourselves contribute something thereto. The senses, 
although necessary for all our actual knowledge, are not suffi- 
cient to give it all to us, since the senses never give us anything 
but examples, i.e. particular or individual truths. Now all the 
examples which confirm a general truth, whatever their num- 
ber, do not suffice to establish the universal necessity of that 
same truth, for it does not follow that what has happened will 
happen in the same way. For example, the Greeks and the 
Romans, and all the other peoples of the earth known to the 
ancients, have always observed that before the lapse of twenty- 
four hours day changes into night, and night into day. But 
we would be deceived, if we believed that the same law holds 
good everywhere else; for since then, the contrary has been 
experienced in the region of Nova Zembla. And he would 
still be in error who believed that, in our climates at least, this 
is a necessary and eternal truth, which will always endure, 
since we must think that the earth, and the sun even, do not 
necessarily exist, and that there will perhaps be a time when 
this beautiful star, together with its whole system, will not 
longer exist, at least in its present form. Whence it appears 

1 For a very full nomenclature of these principles, see Hamilton's Reid, 
Note A., § V., Vol. II., pp. 755-770. 8th ed., Edinburgh and London, 1880. — Tr. 



44 LEIBNITZ'S CRITIQUE OF LOCKE 

that necessary truths such as are found in pure mathematics, 
and particularly in arithmetic and in geometry, must have 
principles whose proof does not depend upon examples, nor 
consequently upon the testimony of the senses, although with- 
out the senses it would never have occurred to us to think of 
them. This distinction must be carefully made, and was so 
well understood by Euclid, that he often proved by the reason, 
what is sufficiently seen through experience and by sensible 
images. Logic also, together with metaphysics and ethics, one 
of which shapes theology and the other jurisprudence, both 
natural (sciences), are full of such truths, and consequently 
their proof can come only from internal principles which are 
called innate. It is true that Ave must not imagine that these 
eternal laws of the reason can be read in the soul as in an open 
book, as the praetor's edict is read upon his album without diffi- 
culty and research ; but it is sufficient that they can be discov- 
ered in us by dint of attention, for which the senses furnish 
occasions, and successful experience serves to confirm reason, 
in much the same way as proofs in arithmetic serve for the 
better avoidance of error in calculating when the reasoning 
is long. Herein, also, human knowledge differs from that 
of the brutes : the brutes are purely empirics and only guide 
themselves by examples ; for, so far as we can judge of them, 
they never attain to the formation of necessary propositions ; 
while men are capable of demonstrative sciences. It is also 
for this reason that the faculty the brutes have for making 
consecutions is something inferior to the reason of man. The 
consecutions of the brutes are merely like those of simple 
empirics, who claim that what has sometimes happened will 
happen again in a case where something strikes them as similar, 
without being able to judge whether the same reasons hold 
good. This is why it is so easy for men to entrap the brutes, 
and so easy for simple empirics to make mistakes. This is 
why persons who have become skilful through age and experi- 
ence are not exempt (from error) when they depend too much 
upon their past experience, as has happened to many in civil 
and military affairs ; because they do not consider sufficiently 
that the world changes, and that men become more skilful by 
finding a thousand new dexterities, while the deer and hares 
of the present do not become more cunning than those of the 



ON HUMAN UNDERSTANDING 45 

past. The consecutions of the brutes are only a shadow of 
reasoning, i.e. are only connections of the imagination and 
passages from one image to another, because in a new juncture 
which appears similar to the preceding they expect anew that 
connection which they formerly met with, as if things were 
united in fact because their images are united in the memory. 
It is true that reason also counsels us to expect ordinarily to see 
that happen in the future which is conformed to a long past 
experience, but it is not on this account a necessary and infalli- 
ble truth, and success may cease when least expected, when 
the reasons change which have sustained it. Therefore the 
wisest men do not so commit themselves to it as not to try to 
discover, if possible, something of the reason of this fact in 
order to judge when it is necessary to make exceptions. For 
reason is alone capable of establishing sure rules, and supply- 
ing what is wanting to those which were not such by inserting 
their exceptions ; and of finding at length certain connections 
in the force of necessary consequences, which often furnish 
the means of foreseeing the result without the necessity of 
experiencing the sense-connections of images, to which the 
brutes are reduced, so that that which justifies the internal 
principles of necessary truths also distinguishes man from the 
brutes. 

Perhaps our clever author will not wholly differ from my 
view. For after having employed the whole of his first book 
in rejecting innate intelligence, taken in a certain sense, he 
nevertheless, at the beginning of the second and in the sequel, 
admits that ideas, which do not originate in sensation, come 
from reflection. Now reflection is nothing else than attention 
to what is in us, and the senses do not give us what we already 
carry with us. That being so, can it be denied that there is 
much that is innate in our mind, since we are innate, so to 
speak, in ourselves ? and that there is in us : being, unity, 
substance, duration, change, action, perception, pleasure, and 
a thousand other objects of our intellectual ideas ? And these 
objects being immediate to our understanding and always pres- 
ent (although they cannot always be perceived by reason of 
our distractions and needs), what wonder that we say that these 
ideas with all depending upon them are innate in us ? I have 
made use also of the comparison of a block of marble which 



46 LEIBNITZ'S CRITIQUE OE LOCKE 

has veins, rather than of a block of marble wholly even, or of 
blank tablets, i.e. of what is called among philosophers a tabula 
rasa. For if the soul resembled these blank tablets, truths 
would be in us as the figure of Hercules is in the marble, when 
the marble is wholly indifferent to the reception of this figure 
or some other. But if there were veins in the block which 
should indicate the figure of Hercules rather than other fig- 
ures, this block would be more determined thereto, and Her- 
cules would be in it as in some sense innate, although it would 
be needful to labor to discover these veins, to clear them by 
polishing, and by cutting away what prevents them from ap- 
pearing. Thus it is that ideas and truths are for us innate, as 
inclinations, dispositions, habits, or natural potentialities, and 
not as actions ; although these potentialities are always accom- 
panied by some actions, often insensible, which correspond to 
them. 

It seems that our clever author claims that there is nothing 
virtual in us, and indeed nothing of which we are not always 
actually conscious ; but he cannot take this rigorously, other- 
wise his opinion would be too paradoxical ; since, moreover, 
acquired habits and the stores of our memory are not always 
perceived and do not even always come to our aid at need, 
although we often easily recall them to the mind upon some 
slight occasion which makes us remember them, just as we 
need only the beginning of a song to remember it. 1 He limits 
his thesis also in other places, by saying that there is nothing 
in us of which we have not at least formerly been conscious. 
But besides the fact that no one can be assured by reason 
alone how far our past apperceptions, which we may have for- 
gotten, may have gone, especially according to the Platonic 
doctrine of reminiscence which, wholly fabulous as it is, is in 
no respect incompatible at least in part with reason wholly 
pure: besides this, I say, why must we acquire all through 
the perception of external things, and nothing be unearthed in 
ourselves ? Is our soul then by itself such a blank that besides 
the images borrowed from without, it is nothing ? This is not 
an opinion (I am sure) that our judicious author could approve. 

1 Erdmann and Jacques read : " le commencement d'une chanson pour nous 
faire ressouvenir du reste," i.e. the beginning of a song to remind us of the 
rest. — Tr. 



ON HUMAN UNDERSTANDING 



And where do we find tablets that have no variety in them- 
selves ? For we never see a plane perfectly even and uniform. 
Why, then, could we not furnish also ourselves with something 
of thought from our own depths if we should dig therein ? 
Thus I am led to believe that at bottom his opinion upon this 
point is not different from mine, or rather from the common 
view, inasmuch as he recognizes two sources of our knowledge, 
the Senses and Reflection. 

I do not know whether it will be so easy to harmonize 
him with us and with the Cartesians, when he maintains 
that the mind does not always think, and particularly that 
it is without perception when we sleep without dreaming; 
and he objects 1 that since bodies can exist without motion, 
souls can also exist without thought. But here I make 
a somewhat different reply than is customary, for I hold 
that naturally a substance cannot exist without action, and that 
there is indeed never a body without movement. Experience 
already favors me, and you have only to consult the book of 
the distinguished Mr. Boyle against absolute rest, to be con- 
vinced of it ; but I believe reason favors it also, and this is one 
of the proofs I have for doing away with atoms. 

Moreover, there are a thousand indications which make us 
think that there are at every moment an infinite number of 
perceptions in us, but without apperception and reflection, i.e. 
changes in the soul itself of which we are not conscious, be- 
cause the impressions are either too slight and too great in 
number, or too even, so that they have nothing sufficiently 
distinguishing them from each other; but joined to others, 
they do not fail to produce their effect and to make themselves 
felt at least confusedly in the mass. Thus it is that habit 
makes us take no notice of the motion of a mill or a waterfall 
when we have lived quite near it for some time. It is not 
that the motion does not always strike our organs, and that 
something no longer enters into the soul corresponding 
thereto, in virtue of the harmony of the soul and the body, 
but these impressions which are in the soul and the body, be- 
ing destitute of the attractions of novelty, are not strong 
enough to attract our attention and our memory, attached to 
objects more engrossing. For all attention requires memory, 
1 Erdmaim and Jacques read : " II dit que," i.e. He says that. — Tb. 



LEIBNITZ'S CRITIQUE OF LOCKE 



and often when we are not admonished, so to speak, and 
warned to take note of some of our own present perceptions, 
we allow them to pass without reflection, and even without 
being noticed ; but if any one directs our attention to them 
immediately after, and makes us notice, for example, some 
noise which was just heard, we remember it, and are conscious 
of having had at the time some feeling of it. Thus there 
were perceptions of which we were not conscious at once, con- 
sciousness arising in this case only from the warning after 
some interval, however small it may be. And to judge still 
better of the minute perceptions which we cannot distinguish 
in the crowd, I am wont to make use of the example of the 
roar or noise of the sea which strikes one when on its shore. 
To understand this noise as it is made, it would be necessary 
to hear the parts which compose this whole, i.e. the noise of 
each wave, although each of these little noises makes itself 
known only in the confused collection of all the others, i.e. in 
the roar itself, and would not be noticed if the wave which 
makes it were alone. For it must be that we are affected a 
little by the motion of this wave, and that we have some per- 
ception of each one of these noises, small as they are ; other- 
wise we would not have that of a hundred thousand waves, 
since a hundred- thousand nothings cannot make something. 
One never sleeps so soundly as not to have some feeble and 
confused sensation, and one would never be awakened by the 
greatest noise in the world if he did not have some perception 
of its small beginning; just as one would never break a rope 
by the greatest effort in the world if it were not stretched 
and lengthened a little by smaller efforts, although the slight 
extension they produce is not apparent. 

These minute perceptions are, then, of greater efficacy in 
their results than one supposes. They form I know not what, 
these tastes, these images of the sense-qualities, clear in the 
mass, but confused in the parts, these impressions which sur- 
rounding bodies make upon us, which involve the infinite, this 
connection which each being has with all the rest of the uni- 
verse. We may even say that in consequence of these minute 
perceptions, the present is big with the future and laden with 
the past, that all things conspire (avjXTrvoia iravra, as Hip- 
pocrates said), and that in the least of substances eyes as 



ON HUMAN UNDERSTANDING 49 

penetrating as those of God could read the whole course of 
the things in the universe. 

Quae sint, quae fuerint, quae mox futura trahantur. 1 

These insensible perceptions indicate also and constitute the 
same individual who is characterized by the traces or expres- 
sions which they conserve of preceding states of this individual, 
in making the connection with his present state ; and they can be 
known by a superior mind, even if this individual himself should 
not be aware of them, i.e. when there would no longer be in him 
the express recollection of them. But they (these perceptions, 
I say) furnish, indeed, the means of finding again this recollec- 
tion at need by the periodic developments which may some day 
happen. It is for this reason that death can be only a sleep, and 
cannot, indeed, continue, the perceptions ceasing merely to be 
sufficiently distinguished, and being reduced in the animals to a 
state of confusion which suspends consciousness, but which can- 
not last always ; not to speak 2 here of man, who must have in 
this regard great privileges in order to preserve his personality. 
It is also by means of the insensible perceptions that this 
admirable pre-established harmony of the soul and the body, 
and indeed of all the monads or simple substances, is ex- 
plained ; 3 which supplies the place of the unmaintainable 
influence of one upon the others, and which in the judgment 
of the author of the most excellent of dictionaries exalts the 
grandeur of the divine perceptions beyond what has ever been 
conceived. After this I would add little if I should say that 
it is these minute perceptions which determine us in many 
junctures without being thought of, and which deceive the 
vulgar by the appearance of an indifference of equilibrium, as 
if we were entirely indifferent whether we turned (for ex- 
ample) to the right or to the left. It is not needful also that 
I notice here, as I have done in the book itself, that they 
cause that uneasiness which I show to consist in something 
which differs from pain only as the small from the great, and 
which, however, often constitutes our desire and even our 

1 Erdmann reads : qux mox, etc. ; Jacques : qvse mox ventura trahantur. 
Gerhardt's reading: " que " is evidently an error. — Tr. 

2 Erdmann and Jacques omit: "pour ne parler icy de l'homme qui doit 
avoir en cela des grands privileges pour garder sa personalite'." — Tr. 

3 Erdmann and Jacques read " j'explique," I explain. —Tr. 

E 



50 LEIBNITZ'S CRITIQUE OF LOCKE 

pleasure by giving to it an exciting flavor. It is also 1 the 
insensible parts of our sensible perceptions, which produce 
a relation between the perceptions of colors, heat, and other 
sensible qualities, and between the motions in bodies which 
correspond to them ; while the Cartesians together with 
our author, penetrating as he is, conceive the perceptions 
which we have of these qualities as arbitrary, i.e. as if God 
had given them to the soul according to his good pleasure, 
without any regard to any essential relation between these 
perceptions and their objects : a view which surprises me 
and which appears to me little worthy of the wisdom of 
the Author of things, who does nothing without harmony and 
without reason. 

In a word, the insensible perceptions are as eminently use- 
ful in Pneumatology 2 as are the insensible corpuscles in 
Physics, and it is equally unreasonable to reject the one or 
the other under the pretext that they are out of reach of our 
senses. Nothing is accomplished all at once, and it is one of 
my great maxims, and one of the most verified, that nature 
makes no leaps : a maxim which I called the Law of Continuity, 
when I spoke of it in the first "Nouvelles de la Eepublique 
des Lettres," 3 and the use of this law is very considerable in 
Physics. This law declares that we pass always from the small 
to the great, and the reverse, through the medium, in degree as 
in parts, and that motion never springs immediately from rest, 
nor is reduced thereto save by a smaller motion, as one never 
completes the survey of any line or length until he has com- 
pleted a smaller line, although hitherto those who have set 
forth the laws of motion have not observed this law, believing 
that a body can receive in a moment a motion contrary to the 
preceding. And all this makes one indeed think that the 

1 Erdmann and Jacques read : " Ce sont les memes parties insensibles," etc., 
It is the same insensible parts, etc. — Tr. 

2 I.e. Psychology. Cf. Hamilton's Reid, 8th ed., Vol. I., p. 217 a, and note. 
— Tr. 

3 A literary journal published by Pierre Bayle at Amsterdam, 1684-1687 ; 
afterwards continued, at Bayle's request, by Basnage, under the title " Histoire 
de ouvrages des Savants," 1687-1709. Leibnitz published in this journal in 
July, 1698, his Eclaircissement des difficulte's que M. Bayle a trouvees dans le 
systems nouveau de I'union de I'ame et du corps. Gerhardt, Vol. 4, pp. 517- 
524; Erdmann, pp. 150-154; Jacques, Vol. 1, pp. 481-487. Translation, Appen- 
dix, pp. 706-712.— Tr. 



ON HUMAN UNDERSTANDING 



noticeable perceptions also arise by degrees from those which 
are too minute to be observed. To think otherwise, is to have 
little knowledge of the immense subtilty of things which 
always and everywhere surrounds an actual infinite. 

I have also noticed that in virtue of these insensible varia- 
tions, two individual things cannot be perfectly alike, and 
that they must always differ more than numero : a fact which 
destroys the blank tablets of the soul, a soul without thought, 
a substance without action, a vacuum in space, atoms and even 
particles not actually divided in matter, absolute rest, entire 
uniformity in one portion of time, place, or matter, perfect 
globes of the second element, born of cubes perfect and orig- 
inal, and a thousand other fictions of philosophers which arise 
from their incomplete notions, and which the nature of things 
does not allow, and which our ignorance and the little atten- 
tion we give to the insensible let pass, but which cannot be 
made tolerable unless they are limited to the abstractions of 
the mind which protests that it does not deny what it puts 
aside, and thinks should not enter into any present considera- 
tion. Otherwise if it were very well understood, viz. : that 
things of which we are not conscious are neither in the soul 
nor the body, we should be lacking in philosophy as in politics, 
in neglecting to /juKpov, the insensible progressions, while an 
abstraction is not an error, provided we know what it is that 
we feign therein. Just as the mathematicians employ it when 
they speak of the perfect lines which they propose to us, of 
uniform motions and of other regulated effects, although matter 
(i.e. the medley of the effects of the surrounding infinite) always 
makes some exception. It is for the sake of distinguishing the 
considerations and of reducing so far as we may do so the effects 
to reasons, and of foreseeing some of their consequences, that 
we proceed thus. For the more we are careful to neglect no 
consideration that we can regulate, the more practice corre- 
sponds to theory. But it belongs only to the supreme Reason, 
whom nothing escapes, distinctly to comprehend all the infinite 
and to see all the reasons and all the consequences. All that 
we can do in regard to infinites is to know them confusedly, 
and to know at least distinctly that they are such ; otherwise 
we judge very wrongly of the beauty and the grandeur of the 
universe ; so also we could not have a sound Physics explaining 



52 LEIBNITZ'S CRITIQUE OF LOCKE 

the nature of bodies in general, and still less a proper Pneuma- 
tology comprising the knowledge of God, of souls, and of simple 
substances in general. 

This knowledge of insensible perceptions serves also to 
explain why and how two souls, human or otherwise, 1 of one 
and the same species never come forth perfectly alike from 
the hands of the Creator and have always each its original 
relation to the points of view which it will have in the uni- 
verse. But this it is which already follows from the remarks 
I have made about two individuals, viz. : that their difference 
is always more than numerical. There is, moreover, another 
point of importance, in respect to which I am obliged to devi- 
ate not only from the opinions of our author, but also from 
those of the majority of modern philosophers : I believe with 
the majority of the ancients that all genii, 2 all souls, all simple 
created substances, are always joined to a body, and that there 
are never souls entirely separated. I have a priori reasons for 
my view ; but the doctrine will be found to have this advan- 
tage, that it resolves all the philosophical difficulties as to the 
condition of souls, their perpetual conservation, their immor- 
tality, and their operation. The difference between one of 
their states and another, never being and never having been 
other than that of more sensible to less sensible, of more 
perfect to less perfect, or the reverse, this doctrine renders 
their past or future state as explicable as that of the present. 
One feels sufficiently, however little reflection he makes, that 
this is rational, and that a leap from one state to another 
infinitely different could not be natural. I am astonished 
that by leaving the natural without reason, the schoolmen 
have been willing purposely to plunge themselves into very 
great difficulties, and to supply matter for apparent triumphs 
of the strong-minded, all of whose reasons fall at once by this 
explanation of things, in which there is no more difficulty in 
conceiving the conservation of souls (or rather, according to 
my view, of the animal) than there is in conceiving the change 
of the caterpillar into the butterfly, and the conservation of 
thought in sleep, to which Jesus Christ has divinely well com- 
pared death. I have already said also that sleep could not 

1 Erdmann reads : " ou deux choses," or two things. — Te. 

2 I.e. Angels and archangels. — Tr. 



ON HUMAN UNDERSTANDING 53 

last always, and it will last least or almost not at all in the 
case of rational souls who are always destined to preserve the 
personality which has been given them in the City of God, 
and consequently remembrance : and this in order to be more 
susceptible of chastisements and recompenses. And I add 
further that in general no derangement of the visible organs 
is capable of throwing things into entire confusion in the 
animal or of destroying all the organs and depriving the soul 
of all its organic body and of the ineffaceable remains of all 
preceding traces. But the ease . with which the ancient doc- 
trine of subtile bodies connected with the angels (which was 
confounded with the corporeality of the angels themselves) 
has been abandoned, and the introduction of pretended sepa- 
rate intelligences in creatures (to which those who make the 
heavens of Aristotle revolve have contributed much), and 
finally the poorly understood view into which we have fallen, 
that the souls of brutes could not be preserved without falling 
into metempsychosis, and 1 without conducting them from body 
to body, and the perplexity into which men have fallen by 
their ignorance of what to do with them, have caused us, in 
my opinion, to neglect the natural explanation of the conserva- 
tion of the soul. This has done much harm to natural relig- 
ion, and has caused many to believe that our immortality 
was only a miraculous grace of God, of which also our cele- 
brated author speaks with some hesitation, as I shall presently 
remark. But it would be well had all those who are of this 
opinion spoken as wisely and in as good faith as he, for it is to 
be feared that many who speak of immortality as a grace do 
so only to keep up appearances, and resemble at bottom these 
Averroists and some bad Quietists who picture to themselves 
an absorption and the reunion of the soul with the ocean 
of divinity : a notion whose impossibility my system alone 
perhaps evinces. 

It seems also that we differ further in regard to matter, in 
that the author thinks that a vacuum is necessary to motion, 
because he thinks that the minute parts of matter are rigid. 
And I admit that if matter were composed of such parts, 

1 Gerhardt's text is: "et sans les promener de corps en corps, et l'embar- 
ras ou Ton a este en ne sachant ce qu'on en devoit faire." Erdmann and 
Jacques omit the clause. — Tr. 



54 LEIBNITZ'S CRITIQUE OE LOCKE 

motion in a plenum would be impossible, as if a room were 
full of a quantity of little pebbles without there being the 
least empty space. But this supposition, for which there 
appears also to be no reason, is not admissible, although this 
learned author goes as far as to believe that rigidity or cohe- 
sion of the minute parts makes the essence of the body. It is 
necessary rather to conceive space as full of a matter origi- 
nally fluid, susceptible of all the divisions, and even actually 
subject to divisions and subdivisions to infinity, but with 
this difference, however, that it is divisible and divided un- 
equally in different parts on account of the motions which 
more or less concur there. This it is which causes matter to 
have everywhere a degree of rigidity as well as of fluidity, and 
no body to be hard or fluid in the highest degree, i.e. no atom 
to be found of an insurmountable hardness nor any mass 
entirely indifferent to division. The order, also, of nature, and 
particularly the law of continuity, destroy equally the one and 
the other. 

I have also shown that cohesion, which by itself would not 
be the effect of impulse or of motion, would cause a traction, 
taken strictly. For if there were a body originally rigid, — for 
example, an Epicurean atom, — which should have a part pro- 
jecting like a hook (since we can imagine atoms of all sorts of 
shapes), this hook pushed would draw with it the rest of this 
atom ; i.e. the part which is not pushed, and which does not 
fall in the line of the impulsion. Our learned author, how- 
ever, is for himself opposed to these philosophic tractions, 
such as were formerly attributed to the abhorrence of a 
vacuum, and he reduces them to impulsions, maintaining with 
the moderns that one part of matter works immediately upon 
another only by pushing it by contact, in which I think they 
are right, because otherwise there is nothing intelligible in the 
operation. 

I must not, however, conceal the fact that I have noticed a 
sort of retraction by our excellent author on this subject, 
whose modest sincerity I cannot forbear praising in this 
respect as much as I have admired on other occasions his 
penetrating genius. It is in his reply to the second letter of 
the late Bishop of Worcester, 1 printed in 1699, p. 408, where, 

1 Edward Stillingfleet, 1635-1699: Bishop oi: Worcester, 1689-1699. — Tk. 



ON HUMAN UNDERSTANDING 55 

in order to justify the view which he had maintained against 
this wise prelate, viz. : that matter might think, he says among 
other things: U I admit that I said (Essay on Understanding, 
Book II. chap. 8, § 11) that body acts by impulse and not 
otherwise. This also was my vieiv when I wrote it, and even now 
I cannot conceive its action in any other way. But since then I 
have been convinced by the judicious Mr. Newton's incomparable 
book that there is too much presumption in wishing to limit the 
power of God by our limited conceptions. The gravitation of 
matter ioioards matter in ivays inconceivable to me, is not only a 
devionstratio?i that God, when it seems to him good, can put into 
bodies powers and modes of acting ivhich are beyond what can be 
derived from our idea of body or explained by tohat we know of 
matter; but it is furthermore an incontestable instance that he has 
really done so. I shall therefore take care to correct this passage 
in the next edition of my book." 1 I find that in the French 
version of this book, made undoubtedly from the latest edi- 
tions, the matter has been put thus in this § 11 : It is evident, 
at least so far as we can conceive it, that it is by impulse and 
not otherivise that bodies act on each other; for it is impossible 
for us to understand how the body can act upon what it does not 
touch, which is the same as to imagine that it can act ivhere it 
is not. 

I can only praise this modest piety of our celebrated author, 
who recognizes that God can do more than we can understand, 
and that thus there may be inconceivable mysteries in the 
articles of faith ; but I should not wish to be obliged to recur 
to the miracle in the ordinary course of nature and to admit 
powers and operations absolutely inexplicable. Otherwise too 
much license will be given poor philosophers, under cover of 
what God can do, and by admitting these centripetal virtues or 
these immediate attractions from afar without being able to 
make them intelligible, I see nothing to hinder our Scholastics 
from saying that everything is done simply by their faculties 
and from maintaining their intentional species which proceed 

I I have retranslated the passage from the French version, as given hy Ger- 
hardt. For the original, cf. Locke, Philos. Works (Bohn's ed.), Vol. II., p. 395. 
The entire letter is found in Locke's Works, Vol. I., pp. 578-774; this particu- 
lar passage, p. 754. Edition of 4 vols., 4to. 7th ed., 1768. Printed for H. Wood- 
fall, A. Millar, and others. — Tr. 



56 LEIBNITZ'S CRITIQUE OE LOCKE 

from objects even to us and find means of entering even into 
our souls. If that is so, 

Omnia jam fient, fieri quae posse negabam. 

So that it seems to me that our author, quite judicious as he 
is, goes here a little too much from one extreme to the other. 
He makes a difficulty in regard to the operations of souls when 
the question is only of admitting what is not sensible, and 
behold he gives to bodies what is not even intelligible; granting 
them powers and actions which surpass in my view all that a 
created spirit can do and understand, since he grants them 
attraction, and that even at great distances without limiting 
them to any sphere of activity, and this in order to maintain a 
view which does not appear less inexplicable, viz. : the possi- 
bility of the thought of matter in the natural order. 

The question which he discusses with the celebrated Prelate 
who attacked him, is, ivJiether matter can think, and as it is an 
important point even for the present work, I cannot refrain 
from entering upon it a little and from taking note of their 
controversy. I will give the substance of their discussion 
upon this subject, and take the liberty of saying what I think 
of it. The late Bishop of Worcester, fearing (but in my 
opinion without good reason) lest our author's doctrine of ideas 
might be liable to certain abuses prejudicial to the Christian 
faith, undertook to examine some points in it in his "Vindication 
of the Doctrine, of the Trinity " ; x and having rendered justice 
to this excellent writer, by recognizing that he thinks the exist- 
ence of spirit as certain as that of body, although one of these 
substances is as little known as the other, he asks (p. 241 sq.) 
how reflection can assure us of the existence of spirit, if God 
can give to matter the power of thought according to the view 
of our author, Book IV., chap. 3, since thus the way of ideas 
which must serve to discern 2 what may suit the soul or the 
body, would become useless ; while he had said in Book II. of 
the Essay on Understanding, chap. 23, §§ 15, 27, 28, that the 
operations of the soul furnish us the idea of mind and the 

1 Published in the autumn of 1696. Of. Alexander Campbell Fraser, Locke, 
pp. 245-246 (Philosophical Classics), Edinburgh: Wm. Blackwood and Sons, 
1890. — Tk, 

2 Gerhardt reads: "discerner"; Erdniann and Jacques: " discuter," to 
discuss, debate, argue. — Tr. 



ON HUMAN UNDERSTANDING 



understanding, and the will renders this idea as intelligible to 
us as the nature of body is rendered intelligible to us by solid- 
ity and impulse. This is how our author replies in his first 
letter (p. 65 sq.) : " I believe I have proved that there is a spirit- 
ual substance in us, for we experience in ourselves thought. Noiv 
this action or this mode cannot be the object of the idea of a thing 
subsisting by itself and consequently this mode needs a support, a 
subject, in which it may inhere, and the idea of this support forms 
what we call substance. . . . For since the general idea of sub- 
stance is everywhere the same, it follows that the modification, 
which is called thought or power of thinking, being joined to it, 
there results a mind without the necessity of considering what 
other modification it has besides; i.e. whether it has solidity or 
not. And, on the other hand, the substance which has the modifi- 
cation called solidity will be matter, whether thought is joined to it 
or not. But if by a spiritual substance you mean an immaterial 
substance, I admit that I have not jjroved that there is one in us, 
and that it cannot be demonstrably proved on my principles. Al- 
though ivhat I have said on the systems of matter (Book IV., 
chap. 10, § 16) in proving that God is immaterial, renders it in 
the highest degree probable, that the substance which thinks in us 
is immaterial. . . . However, I have shoivn [the author adds, 
p. 68] that the great ends of religion and of morals are assured 
by the immortality of the soul, without the need of supposing its 
immateriality." l 

The learned Bishop in his reply to this letter, in order to 
make it evident that our author held another view, when he 
wrote the second book of the Essay, quotes, p. 51, this passage 
(taken from the same book, chap. 23, § 15), where it is said, that 
by the simple ideas which we have deduced from the opierations of 
our mind, we can form the complex idea of a mind. And that 
putting together the ideas of thought, of perception, of liberty, and 
of power to move our body, we have as clear a notion of immate- 
rial substances as of material. He quotes still other passages 
to show that the author opposes mind to body. And he says 
(p. 54) that the ends of religion and of morals are the better 

1 1 have retranslated the passage from the French version as given hy Ger- 
hardt. For the original, cf. Locke, PMlos. Works (Bonn's ed.), Vol. II., 
p. 387. The entire letter is found in Locke's Works, Vol. I., pp. 458-517 ; this 
particular passage, p. 477. Edition of 4 vols., 4to. 7th ed., 1768. Printed for 
H. Woodfall, A.' Millar, and others. — Tr. 



58 LEIBNITZ'S CRITIQUE OF LOCKE 

assured by proving that the soul is immortal by its nature, i.e. 
immaterial. He quotes also (p. 70) this passage, that the ideas 
we have of particular and distinct kinds of substances are nothing 
else than different combinations of simple ideas; 1 and that thus 
the author believed that the idea of thinking and of willing 
gave another substance different from that which the idea of 
solidity and of impulse gives, and that (§ 17) he remarks that 
these ideas constitute the body as opposed to mind. 

The Bishop of Worcester might add that from the fact that 
the general idea of substance is in the body and in the mind, 
it does not follow that their differences are modifications of one 
and the same thing, as our author has just said in the part of 
his first letter which I have quoted. It is necessary carefully 
to distinguish between modifications and attributes. The 
faculties of having perception and of acting, extension, solid- 
ity, are attributes or perpetual and principal predicates ; but 
thought, impetuosity, figures, movements, are modifications of 
these attributes. Furthermore, we must distinguish between 
jjhysical (or, rather, real) genus and logical or ideal genus. 
Things which are of the same physical genus, or which are 
homogeneous, are of the same matter, so to speak, and may 
often be changed the one into the other by the change of mod- 
ification, as circles and squares. But two heterogeneous things 
may have a common logical genus, and then their differences 
are not simple accidental modifications of one and the same 
subject, or of one and the same metaphysical or physical mat- 
ter. Thus time and space are very heterogeneous things, and 
we should do wrong to imagine I know not what real common 
subject which had only the continuous quantity in general, 
and whose modifications should cause the rise of time and 
space. 2 Some one will perhaps laugh at these distinctions of 
the philosophers of two genera, the one merely logical, the 
other real ; and of two matters, the one physical, viz. : that of 
bodies, the other metaphysical only or general ; as if some one 
said that two parts of space are of one and the same matter, 
or that two hours are likewise among themselves of one and 

1 Locke, Philos. Works (Bohn's ed.), Vol. 1, p. 426, chap. 23, § 6. — Tr. 

2 Erdmami and Jacques add : " Cepeudant leur genre logique commun est la 
quantite continue," i.e. Nevertheless their common logical genus is the con- 
tinuous quantity. —Tr. 



ON HUMAN UNDERSTANDING 59 

the same matter. Nevertheless, these distinctions are not dis- 
tinctions of terms merely, but of things themselves, and seem 
to come in here very opportunely, where their confusion has 
given rise to a false conclusion. These two genera have a 
common notion, and that of the real genus is common to the 
two matters, so that their genealogy will be as follows : — 

C Logical merely, varied by simple differences. 

Metaphysical only, where 



1 Beat, whose differences are modi 
[ Jications, i.e. Matter. 



there is homogeneity. 
Physical, where there is 
solid homogeneous mas 



I have not seen the second letter of the author to the 
Bishop, and the reply which this prelate makes to it scarcely 
touches the point relating to the thinking of matter. But the 
reply of our author to this second answer returns to it. God 
(says he, nearly in these words, p. 397) adds to the essence of 
matter the qualities and perfections which please him r simple 
movement in some parts, but in plants, vegetation, and in ani- 
mals, sentiency. Those who agree up to this point, cry out as 
soon as we go a step farther, and say that God can give to matter 
thought, reason, will, as if this destroyed the essence of matter. 
But to prove it, they allege that thought or reason is not included 
in the essence of matter, a point of no consequence, since move- 
ment and life are not included therein either. They assert, also, 
that we cannot conceive of matter as thinking; but our conception 
is not the measure of God's power} After this he cites the ex- 
ample of the attraction of matter (p. 99, but especially p. 408), 
where he speaks of the gravitation of matter towards matter, 
attributed to Mr. Newton (in the terms which I have quoted 
above), admitting that we can never conceive the manner of it. 
This is in reality to return to the occult, or, what is more, in- 
explicable qualities. He adds (p. 401) that nothing is more 
calculated to favor the sceptics than to deny what we do not 
understand ; and (p. 402) that we do not conceive even how the 
soul thinks. He will have it (p. 403) that, since the two sub- 

i For the original, cf. Locke, Philos. Works (Bohn's ed.), Vol. 2, pp. 390, 391. 
The entire letter is found in Locke's Works, Vol. 1, pp. 578-774 ; this particu- 
lar passage, pp. 749, 750. Edition of 4 vols., 4to. 7th ed., 1768. Printed for 
H. Woodfall, A. Miller, and others. — Tr. 



60 LEIBNITZ'S CRITIQUE OF LOCKE 

stances, material and immaterial, are capable of being conceived 
in their naked essence without any activity, it depends upon 
God to give to each the power of thought. And he wishes to 
take advantage of the admission of his opponent, who had 
granted sentiency to the brutes, but who would riot grant them 
any immaterial substance. He claims that liberty, conscious- 
ness (p. 408), and the power of abstract thought (p. 409) can 
be bestowed upon matter, not as matter, but as enriched by a 
divine power. Finally, he quotes (p. 434) the remark of a 
traveller as eminent and judicious as M. de la Loubere, 1 that 
the pagans of the East acknowledge the immortality of the 
soul without being able to comprehend its immateriality. 

On all this I would remark, before coming to the explana- 
tion of my view, that it is certain that matter is as little capa- 
ble of mechanically producing feeling, as of producing reason, 
as our author admits ; that in truth I acknowledge that it is 
not permissible to deny what we do not understand, but I add 
that we are right in denying (at least in the natural order) 
what is absolutely neither intelligible nor explicable. I main- 
tain, also, that substances (material or immaterial) cannot be 
conceived in their naked essence without any activity ; that 
activity belongs to the essence of substance in general ; that, 
finally, the conception of creatures is not the measure of God's 
power, but that their conceptivity, or power of conception, is 
the measure of nature's power; all this is in harmony with 
the natural order, being capable of being conceived or under- 
stood by some creature. 

Those who understand my system will think that I cannot 
wholly agree with the one or the other of these two excellent 
authors, whose discussion, however, is very instructive. But 
to explain myself distinctly, it is necessary before all things 
to consider that the modifications which may belong naturally 
or without miracle to a subject must come to it from the limi- 
tations or variations of a real genus, or of a constant and abso- 
lute original nature. For it is thus that Philosophers dis- 

i La Loubere, Simon de, 1642-1729. Sent by Louis XIV. in 1687 to Siam, 
to establish diplomatic aud commercial relations between that kingdom and 
France. While there he collected a large amount of exact and interesting 
information concerning the country, its history, customs, religion, etc., which, 
on his return, he published in his Da royaume de Siam, Paris, 1691 ; English 
translation, London, 1693. — Tr. 






ON HUMAN UNDERSTANDING 61 

tinguish the modes of an absolute being from that being itself ; 
as it is known that size, figure, and movement are manifestly 
limitations and variations of corporeal nature. For it is clear 
how a limited extension gives figures, and that the change 
which is made in it is nothing but motion. And whenever 
we find any quality in a subject, we must believe that if we 
understood the nature of this subject and of this quality, we 
should conceive how this quality can result therefrom. Thus 
in the order of nature (miracles aside) it is not optional with 
God to give to substances indifferently such or such qualities, 
and he will never give to them any, save those which will be 
natural to them, i.e. which can be derived from their nature as 
explicable modifications. Thus it may be asserted that matter 
will not naturally possess the attraction mentioned above, and 
will not proceed of itself in a curved line, because it is impossi- 
ble to conceive how this takes place there, i.e. to explain it 
mechanically, while that which is natural must be capable of 
becoming distinctly conceivable if we were admitted into the 
secrets of things. This distinction between what is natural 
and explicable and what is inexplicable and miraculous 
removes all the difficulties, and by rejecting it, we should 
maintain something worse than the occult qualities ; and in so 
doing would renounce philosophy and reason, by opening 
retreats for ignorance and idleness, though a dead system, 
which admits not only that there are qualities which we do not 
understand, of which there are only too many, but also that 
there are some which the greatest mind, if God gave him every 
possible opening, could not comprehend, i.e. which would be 
either miraculous or Avithout rhyme and reason ; and also that 
God should work miracles ordinarily would be without rhyme 
and reason, so that this hypothesis would destroy equally our 
philosophy which seeks reasons, and the divine wisdom which 
furnishes them. 

Now as to thought, it is certain, and the author admits it 
more than once, that it could not be an intelligible modifica- 
tion of nature or one which could be comprised therein and 
explained, i.e. that a being who feels and thinks is not a mech- 
anism like a watch or a mill, so that we might conceive sizes, 
figures, and movements, whose mechanical conjunction might 
produce something thinking, and even feeling in a mass in 



62 LEIBNITZ'S CEITIQUE OF LOCKE 

which there was nothing of the kind, which would cease also 
in the same manner upon the derangement of this mechanism. 
It is not then a natural thing for matter to feel and think, and 
this can happen within it only in two ways, of which one will 
be that God should unite with it a substance to which thought 
is natural, and the other that God by a miracle should put 
thought therein. In this, then, I am wholly of the opinion of 
the Cartesians, except that I extend it even to the brutes, 
and that I believe they have sentiency and (properly speak- 
ing) immaterial souls, and are as imperishable as the atoms of 
Democritus or Gassendi, while the Cartesians, perplexed with- 
out reason by the souls of brutes, and not knowing what they 
are to do with them if they are preserved (for want of having 
thought of the conservation of the same animal reduced to 
miniature), have been compelled to refuse even sentiency to the 
animals against all appearances and contrary to the judgment 
of the human race. But if any one should say that God at 
least may add the faculty of thinking to the prepared mechan- 
ism, I should reply that if this were done, and if God added 
this faculty to matter without putting therein at the same 
time a substance which was the subject of inhesion of this 
same faculty (as I conceive it), i.e. without adding thereto an 
immaterial soul, it would be necessary that matter should be 
miraculously exalted in order to receive a power of which it is 
naturally incapable ; as some scholastics * claim that God ex- 
alts fire even to the point of giving it the force to burn imme- 
diately spirits separated from matter, a thing which would be 
a miracle, pure and simple. And it is enough that it cannot 
be maintained that matter thinks without putting into it an 
imperishable soul, or a miracle, and that thus the immortality 
of our souls follows from what is natural, since their extinc- 
tion can be maintained only by a miracle, whether by exalting 
matter or by annihilating the soul. For we know well that 
God's power can make our souls mortal, wholly immaterial 
(or immortal by nature alone) as they may be, since he can 
annihilate them. 

Now this truth of the immateriality of the soul is undoubt- 

1 Erdmann and Jacques read : " Quelques scholastiques ont pretendu quelque 
chose d'approchant savoir," i.e. Some scholastics have claimed something 
like this : viz. — Tr. 



ON HUMAN UNDERSTANDING 63 

edly of importance. For it is infinitely more advantageous to 
religion and morality, especially in our times (when many 
people hardly respect revelation alone and miracles ] ), to show 
that souls are immortal by nature, — and that it would be a mir- 
acle if they were not, — than to maintain that our souls ought 
naturally to die, but that it is in virtue of a miraculous grace 
grounded in the promise of God alone that they do not die. 
Also for a long time it has been known that those who have 
desired to destroy natural religion and to reduce all to revealed 
religion, as if reason taught us nothing regarding it, have been 
looked upon with suspicion ; and not always without reason. 
But our author does not belong to that number. He maintains 
the demonstration of the existence of God, and he attributes 
to the immateriality of the soul a probability in the highest de- 
gree, which could consequently pass for a moral certainty, so 
that I think that, having as much sincerity as penetration, he 
could easily accommodate himself to the doctrine which I have 
just set forth, and which is fundamental in every rational phi- 
losophy. For otherwise I do not see how one can prevent him- 
self from falling back into the fanatical philosophy,' 2 ' such as the 
"Philosophia Mosaica" of Fludd, 3 which saves all phenomena by 
attributing them to God immediately and by miracle ; or into 
the barbaric philosophy like that of certain philosophers and 
physicians of the past, which still manifested the barbarity of 
their age, and which to-day is with reason despised, who saved 
appearances by forging purposely occult qualities or faculties 
which they imagined to be like little demons or goblins capa- 
ble of producing without ceremony what is demanded, just as 
if watches marked the hours by a certain horodeictic faculty 
without needing wheels, or as if mills ground the grain by a 
fractive faculty without needing anything resembling mill- 
stones. As to the difficulty that many people have had in 
conceiving an immaterial substance, it will easily cease (at 
least in good part) if they will not demand substances sepa- 
rated from matter, as in fact I do not believe there ever are any 
naturally among creatures. 

1 Erdmann and Jacques omit this clause. — Tr. 

2 Erdmann and Jacques read: " la philosophic ou fanatique," i.e. philosophy 
or fanaticism. — Tr. 

3 Robert Fludd (1574-1637), an English physician and mystical philosopher. 
The Philosophia Mosaica was published at Gouda in 1638. — Tr. 



NEW ESSAYS ON HUMAN UNDERSTANDING 



Book I. — Innate Ideas 
CHAPTER I 1 

ABE THERE INNATE PRINCIPLES IN THE MIND OF MAN ? 

Philaletlies. Having recrossed the sea after finishing my 
business in England, I thought at once of paying you a visit, 
sir, in order to cultivate our former friendship, and to con- 
verse upon matters which lie close to our hearts, and upon 
which I believe I have acquired some new light during my 
long stay in London. When we were living formerly quite 
near each other at Amsterdam, we both took much pleasure 
in making researches into the principles and means of pene- 
trating into the heart of things. Although our opinions often 
differed, this diversity increased our satisfaction, when, in our 
conference together, notwithstanding the contrariety which 
sometimes existed, there mingled nothing disagreeable. You 
were for Descartes 2 and for the opinions of the celebrated 
author 2 of "The Search after Truth," and I found the opinions 
of Gassendi, 2 cleared up by Bernier, easier and more natural. 
Now I feel myself greatly strengthened by the excellent work 
which an illustrious Englishman, with whom I have the honor 
of a particular acquaintance, has since published, and which 
has several times been reprinted in England, under the modest 

1 Book I. of Locke's Essay has four chapters, of which chap. 1 is introduc- 
tory. Chap. 1 of Leibnitz corresponds to chap. 2 of Locke. — Tr. 

2 Rene' Descartes, 1596-1650; Nicolas Malehranche, 1638-1715, his chief 
work, De la Recherche de la Verite, 1674; Pierre Gassendi, 1592-1655, Abrege 
de la Philosophic de Gassendi, 8 vols., 1678, 2d ed., 7 vols., 1684, by Francois 
Bernier. — Tr. 

64 



ch. i] ON HUMAN UNDERSTANDING 65 

title of "An Essay concerning Human Understanding." And 
I am delighted that it has appeared lately in Latin and in 
French, in order that it may be more generally useful. I have 
greatly profited by the reading of this work, and indeed from 
the conversation of the author, with whom I have talked 
often in London, and sometimes at Oates, at the house of my 
Lady Masham, 1 worthy daughter of the celebrated Cudworth, 2 
a great English philosopher and theologian, author of the 
Intellectual System, from whom she has inherited the spirit 
of meditation and the love for good learning, which appeared 
particularly in the friendship which she kept up with the 
author of the Essay. And, as he had been attacked by some 
clever Doctors, I took pleasure in reading also the defence 
which a very wise and very intelligent young lady made for 
him, besides those which he made for himself. This author 
writes in the spirit of the system of Gassendi, which is at 
bottom that of Democritus ; 2 he is for the vacuum and for 
atoms ; he believes that matter might think ; that there are 
no innate ideas, that our mind is a tabula rasa, and that we do 
not always think; and he appears disposed to approve the 
most of the objections which Gassendi has made 3 to Descartes. 
He has enriched and strengthened this system by a thousand 
beautiful reflections ; and I do not at all doubt that now our 
party will triumph boldly over its adversaries, the Peripa- 
tetics and the Cartesians. This is why, if you have not yet 
read this book, I invite you to do so, and if you have read it, 
I ask you to give me your opinion of it. 

Theophilus. I rejoice to see you, on your return after a long 
absence, happy in the conclusion of your important business, 
full of health, steadfast in your friendship for me, and always 
transported with an ardor equal to the search for the most 

1 The correspondence between Leibnitz and Lady Masham is given in full 
by Gerhardt, Vol. 3, pp. 331 sq.— Tr. 

2 Ralph Cudworth, 1617-1688, his principal work, The True Intellectual 
System of the Universe, London, 1678; Democritus, born probably about the 
middle of the fifth century B.C., as he says (Diog. L., IX., 41) he was "still 
young when Anaxagoras," 500-428 B.C., "was already old (veo? Kara vpea-pvTriv 
'Avagayopav)." . . . "The year of his death is unknown," Zeller, Outlines 
of the History of Greek Philosophy, pp. 76, 77, New York: H. Holt & Co., 
1886.— Tr. ' 

3 In Vol. 3 of his Opera, of which two editions were published : by Mont- 
mort, 1655, 6 vols, folio, Lyons ; by Averanius, 1727, also 8 vols, folio. — Tr. 

F 



66 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

important truths. I no less have continued my meditations 
in the same spirit, and I believe I have profited as much as, 
and, not to flatter myself, perhaps more than yourself. -J In- 
deed, my need therein was greater than yours, for you were 
more advanced than I. You were more conversant with spec- 
ulative philosophers, and I was more inclined towards ethics. 
But I have learned more and more how ethics receives strength 
from the solid principles of true philosophy ; therefore I have 
lately studied these principles more diligently, and have begun 
meditations quite new. So that we shall have the means of 
giving ourselves a reciprocal pleasure of long duration in com- 
municating the one to the other our solutions. But it is nec- 
essary for me to tell you, as a piece of news, that I am no 
longer a Cartesian, and that, nevertheless, I am farther re- 
moved than ever from your Gassendi, whose knowledge and 
merit I, for the rest, recognize. I have been impressed with 
a new system, of which I have read something in the " Jour- 
naux des Savans " of Paris, Leipzig, and Holland, and in the 
marvellous Dictionary of Bayle, article "Korarius" 1 ; and since 
then I believe I see a new aspect of the interior of things. 
This system appears to unite Plato 2 and Democritus, Aristotle 2 
and Descartes, the scholastics with the moderns, theology and 
ethics with the reason. It seems to take the beet from all 
sides, and then it goes much farther than any has yet 
gone. I find in it an intelligible explanation of the union of 
soul and body, of which I had before this despaired. I find 
the true principles of things in the Unities of Substance, which 
this system introduces, and in their harmony pre-established 
by the primitive Substance. I find therein a wonderful sim- 
plicity and uniformity, so that it may be said that this sub- 
stance is everywhere and always the same thing, differing 
only in degrees of perfection. I see now what Plato meant 
when he assumed matter to be an existence imperfect and 
transitory ; what Aristotle meant by his Entelechy ; what that 
promise of another life is which Democritus himself made 
according to Pliny ; how far the Sceptics were right in de- 
claiming against the senses ; how animals are in fact automata 

1 Cf. Gerhardt, Vol. 4, pp. 524-554, the article " Rorarius " with Leibnitz's 
remarks. — Tr. 

2 Plato, 427-347 B.C. ; Aristotle, 384-322 b.c. — Tr. 



ch. i] ON HUMAN UNDERSTANDING 67 

according to Descartes, and how they have, nevertheless, souls 
and feeling according to the opinion of mankind ; how it is 
necessary to explain rationally those who have lodged life and 
perception in all things, as Cardan, 1 Campanella, 1 and, better 
than they, the late Countess of Connaway, a Platonist, and our 
friend, the late M. Francois Mercure van Helmont 2 (although 
elsewhere bristling with unintelligible paradoxes), with his 
friend, the late Mr. Henry More. 2 How the laws of nature (a 
good part of which were unknown before this system) have 
their origin in principles superior to matter, and how, never- 
theless, everything takes place mechanically in matter, in 
which respect the spiritualizing authors I just named have 
failed with their Archeei, 3 and even the Cartesians, in believ- 

i Girolamo Cardano, 1501-1576 ; Tommaso Campanella, 1568-1639 ; ef. Erd- 
mann, Grundriss d. Gesch. d. Philos., 3d ed., Vol. 1, §§ 242, 246, Berlin: Wil- 
helm Hertz, 1878, and the English translation of the same, London: Swan 
Sonnenschein & Co., 1889; also the articles "Cardan" and "Campanella" in 
the Encyclopedia Britannica, 9th ed. — Tr. 

2 Van Helmont, 1618-1698: Henry More, 1614-1687. — Tr. 

3 Archmus, i. Modern Latin, from the Greek ipx 6 " ?. a-px~n> that which is at 
the beginning, source, origin, a first principle. Littre' defines the term thus : 
" Arche'e. Terme de physiologie ancienne. Principe immaterial diffe'rent de 
l'ame intelligent et qu'on supposait presider a tous les phenomenes de la 
vie materielle." I.e. "A term of ancient physiology. An immaterial princi- 
ple different from the intelligent soul, and which is supposed to preside over 
all the phenomena of the material life." The Century Dictionary gives the 
following exposition and illustration: "In the philosophy of Paracelsus and 
other spagyrics, mystics, and theosophists, a spirit or invisible man or animal 
of ethereal substance, the counterpart of the visible body, within which it 
resides, and to which it imparts life, strength, and the power of assimilating 
food. The word is said to have been used by Basil Valentine, a German 
chemist of the fifteenth century, to denote the solar heat as the source of the 
life of plants. Paracelsus uses it with the above meaning. It is frequent in 
the writings of Van Helmont, who explains it as a material jDre-existence of the 
human or animal form in posse. He regards the archseus as a fluid, i.e. as a 
semi-material substance like air, and seems to consider it a chemical constituent 
of the blood. Paracelsus has particularly made use of the hypothesis of the 
archseus to explain the assimilation of food. This function of the archseus 
became prominent in medicine. Van Helmont calls it the doorkeeper of the 
stomach (janitor stomachi). There are further divarications of meaning. 
Also spelled Archeus." 

" As for the many pretended intricacies in the instance of the efformation 
of Wasps out of the Carcase of a Horse, I say, the Archei that formed them 
are no parts of the Horse's Soul that is dead, but several distinct Archei that 
do as naturally joyn with the matter of his body, so putrified and prepared, 
as the Crowes come to eat his flesh." — Dr. H. More, Antidote against 
Atheism, app. xi. 

Cf. Leibnitz: Considerations snr le Principe de Vie et sur les Natures Plas- 



68 LEIBNITZ'S CRITIQUE OF LOCKE [ek. i 

ing that immaterial substances altered if not the force, at 
least the direction or determination, of the motions of bodies, 
whereas the soul and the body retain perfectly each its own 
laws, according to the new system, and yet one obeys the 
other as much as is necessary. In fine, it is since I have med- 
itated upon this system that I have found out how the souls 
of beasts and their sensations are in no sense prejudicial to 
the immortality of human souls, or, rather, how nothing is 
more suited to establish our natural immortality than to con- 
ceive that all souls are imperishable (morte carent animce), 
without, however, the fear of metempsychoses, since not only 
the souls, but further, the animals endure and will endure liv- 
ing, feeling, acting ; it is everywhere as here, and always and 
everywhere as with us, according to what I have already said 
to you, except that the conditions of animals are more or less 
perfect and developed, without there ever being a need of 
souls wholly separate, while we nevertheless have always 
spirits as pure as possible, notwithstanding our (physical) 
organs, which cannot disturb by any influence the laws of our 
(spiritual) spontaneity. I find the vacuum and atoms excluded 
in quite another way than by the sophism of the Cartesians, 
grounded in the pretended coincidence of the idea of body and 
extension. I see all things determined and adorned beyond 
anything hitherto conceived; matter everywhere organic, no 
sterile, neglected vacuum, nothing too uniform, everything 
varied, but with order; and, what passes imagination, the 
entire universe in epitome, but with a different aspect in each 
of its parts, and likewise in each of its unities of substance. 
Besides this new analysis of things, I have a better compre- 
hension of that of notions or ideas, and of truths. I under- 
stand what a true, clear, distinct, adequate idea is, if I dare 
adopt this word. I understand what are primitive truths, and 
true axioms, the distinction between necessary truths and 

tiquespar VAuteur de VHarmonie Pree'tablie, published in the "Histoire des 
Ouvrages des Savans," May, 1705, Gerhardt, Vol. 6, pp. 539-546; Erdmann, 
pp. 429-432 ; translation, Duncan, Philos. Works of Leibnitz, pp. 163-169. See 
also Erdmann, Grundriss d. Gesch. d. Philos. 3d ed., Vol. 1, § 241, 7, Vol. 2, 
§ 290, 12, or the English translation of the same. Slight additional information 
may be found in the JEncyclopsedia Britannica, 9th ed., under the article, 
"Medicine," in the part giving an account of Paracelsus and Van Hel- 
mont. — Tr. 



ch. i] ON HUMAN UNDEESTANDING 69 

truths of fact, between the reasoning of men and the consecu- 
tions of animals, which are a shadow of the reasoning of men. 
In short, you will be surprised to hear all that I have to say 
to you, and, above all, to understand how much the knowledge 
of the grandeur and of the perfection of God is therein exalted. 
For I cannot conceal from you, from whom I have had nothing 
concealed, how I have been thrilled now with admiration and 
(if we may dare to make use of the term) with love for this 
sovereign source of things and of beauty, having found that 
what this system discovers surpasses everything one has hith- 
erto conceived. You know that I had gone a little too far 
formerly, and that I began to lean toward the side of the 
Spinozists, 1 who allow God only infinite power, without recog- 
nizing either perfection or wisdom in his case, and regarding 
with contempt the search for final causes, derive everything 
from brute necessity. But these new lights have cured me of 
this ; and since then I sometimes take the name of Theophilus. 
I have read the book of this celebrated Englishman of whom 
you have just spoken. I value it highly, and I have found in 
it some good things. But it seems to me necessary to go 
much farther, and necessary even to turn aside from his views, 
since he has adopted some which limit us more than is neces- 
sary, and lower a little not only the condition of man, but, 
besides, that of the universe. 

Ph. You astonish me in fact with all the marvels which 
you have recited to me in a manner a little too favorable for 
an easy credence of them on my part. However, I will hope 
that there will be something solid among so many novelties 
with which you desire to regale me. In this case you will find 
me very docile. You know that it was always my disposition 
to surrender myself to reason, and that I sometimes took the 
name of Philalethes. This is why, if you please, we will now 
make use of these two names which are so congruous with our 
mental constitution and methods. There are means of pro- 
ceeding to the trial, for — since you have read the book of the 

1 On the relation of Leibnitz to Spinoza, see Leibniz u. Spinoza. Ein 
Beitrag zur Entwickhmgsgeschichte der Leibnizischen Philosophie. Von Prof. 
Dr. Luchvig Stein. Mit neunzehn Ineditis aus dem Nachlass von Leibniz. 
Berlin: G. Reimer, 1890. pp. xvii., 362. Also " Mind," No. 62, p. 298 ; No. 63, pp. 
443 sq., the latter an extended note on Stein's book by Prof. George Croora 
Robertson, the late editor of " Mind." — Tr. 



70 LEIBNITZ'S CRITIQUE OF LOCKE * [bk. i 

celebrated Englishman, which gives me so much satisfaction 
and which treats a good part of the subjects of which you 
were just speaking, and above all, the analysis of our ideas and 
knowledge — it will be the shortest way to follow the thread 
of this work, and to see what you will have to say. 

Th. I approve your proposition. Here is the book. 

§ 1. Ph. [I have read this book so thoroughly that I have 
retained even its expressions, which I shall be careful to fol- 
low. Thus I shall not need to recur to the book, except at 
certain junctures where we shall judge it necessary. We shall 
speak first of the origin of ideas or notions (Book I.), then 
of the different kinds of ideas (Book II.), and of the words 
that serve to express them (Book III.), lastly of the knowl- 
edge and truths which therefrom result (Book IV.) ; and it is 
this last part which will occupy us the most. As for the ori- 
gin of ideas, I believe, with this author and a multitude of 
clever persons, that there are no innate ideas nor innate prin- 
ciples.] And, in order to refute the error of those who admit 
them, it is sufficient to show, as it appears eventually, that 
there is no need of them, and that men can acquire all their 
knowledge without the aid of any innate impression 

Th. [You know, Philalethes, that I have been for a long 
time of another opinion ; that I have always held, as I still 
hold, to the innate idea of God, which Descartes maintained, 
and as a consequence to the other innate ideas, which cannot 
come to us from the senses. Now, I go still farther in con- 
formity to the new system, and I believe even that all the 
thoughts and acts of our soul come from its own depths, with 
impossibility of their being given to it by the senses, as you 
shall see in the sequel. But at present I will put this investi- 
gation aside, and, accommodating myself to the received ex- 
pressions, since in fact they are good and tenable, and one can 
say in a certain sense that the external senses are in part 
causes of our thoughts, I shall consider how in my opinion 
one must say even in the common system (speaking of the 
action of bodies upon the soul, as the Copernicans speak with 
other men of the movement of the sun, and with cause), that 
there are some ideas and some principles which do not come to 
us from the senses, and which we find in ourselves without form- 
ing them, although the senses give us occasion to perceive them. 



en. i] ON HUMAN UNDERSTANDING 71 

I imagine that your clever author has remarked that under the 
name of innate principles one often maintains his prejudices, 
and wishes to free himself from the trouble of discussion, and 
that this abuse doubtless has stirred up his zeal against this 
supposition. He desired, no doubt, to combat the indolence 
and the superficial manner of thinking of those who, under the 
specious pretext of innate ideas and of truths naturally en- 
graved upon the mind, to which we readily give our consent, 
care nothing about investigating or considering the sources, 
the relations, and the certainty of this knowledge. In that I 
am entirely agreed with him, and I go even farther. I would 
that our analysis should not be limited, that definitions should 
be given of all the terms which are capable of definition, and 
that one should demonstrate, or give the means of demonstrat- 
ing, all the axioms which are not primitive, without distin- 
guishing the opinions which men have of them, and without 
caring whether they give their consent or not. There would 
be more profit in this than one thinks. But it seems that the 
author has been carried too far on the other side by his zeal, 
otherwise very praiseworthy. He has not sufficiently distin- 
guished^ in my opinion, the origin of the necessary truths, 
whose source is in the understanding, from that of the truths 
of fact drawn from the experience of the senses, and even 
from those confused perceptions which are in us. You see, 
then, that I do not agree with what you lay down as fact 
— that we can acquire all our knowledge without the need of 
innate impressions. And the sequel will show which of us is 
right.] 

§ 2. Ph. We shall see it indeed. I grant you, my dear The- 
ophilus, that there is no opinion more commonly received than 
that which establishes the existence of certain principles of 
truth in which men generally agree ; this is why they are 
called general notions, kolvol evvoiat ; whence it is inferred 
that these principles must be so many impressions which our 
minds receive with their existence. § 3. But though it were 
certain that there are some principles in which the entire 
human race is agreed, this universal consent would not prove 
that they are innate if one can show, as I believe he can, an- 
other way through which men have been able to reach this 
aniformity of opinion. § 4. But, what is much worse, this 



72 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

universal consent is nowhere found, not even with regard to 
these two celebrated speculative principles (for we shall speak 
about the practical ones later), that whatever is, is; and that 
it is impossible for a thing to be and not to be at the same 
time. For there is a large part of the human race to which 
these two propositions, which will pass doubtless for neces- 
sary truths and for axioms with you, are not even known. 

Th. [I do not ground the certainty of innate principles upon 
universal consent, for I have already told you, Philalethes, 
that my opinion is that we ought to labor to be able to demon- 
strate all the axioms which are not primitive. I grant you 
also that a consent very general, but which is not universal, 
may come from a tradition diffused throughout the human 
race, as the practice of smoking tobacco has been received by 
nearly all nations in less than a century, although some island- 
ers have been found who, not being acquainted with fire even, 
were unable to smoke. Thus some clever people, even among 
theologians, but of the party of Arminius, 1 have believed that 
the knowledge of the Deity came from a very ancient and very 
general tradition ; and I believe indeed that instruction has 
confirmed and rectified this knowledge. It appears, however, 
that nature has contributed to its attainment without learning ; 
the marvels of the universe have made us think of a superior 
power. A child born deaf and dumb has been seen to show 
veneration for the full moon, and nations have been found, 
who seemed not to have learned anything of other peoples, 
fearing invisible powers. I grant you, my dear Philalethes, that 
this is not yet the idea of God that we have and ask for ; but 
this idea itself does not cease to be in the depths of our souls, 
without being put there, as we shall see, and the eternal laws 
of God are in part engraved thereon in a manner still more 
legible and by a species of instinct. But they are practical 
principles of which we shall also have occasion to speak. It 
must be admitted, however, that the inclination we have to 
recognize the idea of God is in human nature. And, even if 
the first instruction therein should be attributed to revelation, 
the readiness which men have always shown to receive this 
doctrine comes from the nature of their souls. 2 But we will 

1 James Arminius, 1560-1609, a distinguished Dutch theologian. — Te. 

2 From this point on Gerhardt, whose edition, it will be remembered, is the 



en. i] ON HUMAN UNDERSTANDING 73 

suppose that these ideas which are innate comprehend incom- 
patible notions. 

§ 19. Ph. Although you maintain that these particular and 
self-evident propositions, whose truth is recognized as soon as 
one hears them stated (as that green is not red), are received 
as consequences of these other more general propositions, 
which are regarded as so many innate principles, it seems that 
you do not at all consider that these particular propositions 
are received as indubitable truths by those who have no knowl- 
edge of these more general maxims. 

Th. I have already replied to that above. We build on these 
general maxims as we build upon the majors, which are sup- 
pressed when we reason by enthymemes ; for, although very 
often we do not think distinctly of what we do in reasoning 
any more than of what we do in walking and leaping, it is 
always true that the force of the conclusion consists in part in 
that which is suppressed and could not elsewhere arise, as you 
will find should you wish to prove it. 

§ 20. Ph. But it seems that general and abstract ideas are 
more foreign to our mind [than notions and particular truths ; 
consequently particular truths will be more natural to the 
mind than the principle of contradiction, of which you admit 
they are only the application]. 

Th. It is true that we commence sooner to perceive particu- 

basis of the present translation, transposes the text as given by Erclmann and 
Jacques as follows : "Mais nous jugerons que ces idees qui sont innees, ren- 
ferment des notions incompatibles," the first three words of which will be 
found in Erdmann, p. 207, b., about two-thirds down the page, Jacques, Vol. 1, 
p. 29, about two-thirds down, the remainder in Erdmann, p. 211, a., at the 
middle of the page, Jacques, p. 36, first third, just preceding § 19 in each case, 
whence the three texts go on in agreement until § 26, G., p. 72, E., p. 212, b., 
J., p. 39. Here the Gerhard t text has the following : " S'ily a des verites innees, 
ne faut il pas qu'il y ait dans la suite, que la doctrine externe ne fait qu'exciter 
icy ce que est en nous " : taking up with the words " dans la suite," the text 
as given by E., p. 207, b., J., p. 29, where it previously left it, the three texts 
continuing again in agreement until the words " des qu'on s'appercoit," G., p. 
79, last third, E., 211, a., at the middle, J., 36, first third, whence G. completes 
his sentence with the last three words of the first sentence of § 26, as given by 
E., 212, b., J., 39, from which point again the three texts substantially agree 
to the end of Chap. 1. It may be added that the texts of Erdmann, Jacques, 
and Janet follow the order of Locke's Essay. Why Gerhardt has transposed 
the text in his edition, I do not know, as he has not alluded to the matter. 
From his statement that " the present impression has been newly compared 
with the original, so far as it is still extant " (Introduction, p. 10), I presume 
that the transposition is clue to his fidelity to this original. — Tr. 



74 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

lar truths when we commence with ideas more complex and 
gross ; but that does not prevent the order of nature from com- 
mencing with the most simple, and the proof of the more par- 
ticular truths from depending upon the more general, of which 
they are only examples. And when we wish to consider what 
is in us virtually and before all apperception, we are right in 
commencing with the most simple. For the general principles 
enter into our thoughts, of which they form the soul and the 
connection. They are as necessary thereto as the muscles and 
sinews are for walking, although we do not at all think of 
them. The mind leans upon these principles every moment, 
but it does not come so easily to distinguish them and to rep- 
resent them distinctly and separately, because that demands 
great attention to its acts, and the majority of people, little 
accustomed to think, has little of it. Have not the Chinese 
like ourselves articulate sounds ? and yet being attached to 
another manner of writing, they have not yet thought of 
making an alphabet of these sounds. Thus it is that one 
possesses many things without knowing it. 

§ 21. Ph. If the mind acquiesces so promptly in certain 
truths, cannot that acquiescence come from the consideration 
itself of the nature of things, which does not allow it to judge 
of them otherwise, rather than from the consideration that 
these propositions are engraved by nature in the mind ? 

Th. Both are true. The nature of things and the nature of 
mind agree. And since you oppose the consideration of the 
thing to the apperception of that which is engraven in the 
mind, this objection itself shows, sir, that those whose side you 
take understand by innate truths only those which would be 
approved naturally as by instinct, and even without knowing 
it, unless confusedly. There are some of this nature, and we 
shall have occasion to speak of them. But what is called nat- 
ural light supposes a distinct knowledge, and very often the 
consideration of the nature of things is nothing else than the 
knowledge of the nature of our mind, and of these innate ideas 
which we have no need to seek outside. Thus I call innate 
the truths which need only this consideration for their verifi- 
cation. I have already replied (§ 5) to the objection (§ 22) 
which claimed that when it is said that innate notions are 
implicitly in the mind, the statement must mean simply that 



ch. i] ON HUMAN UNDEESTANDING 75 

it has the faculty of knowing them ; for I have pointed out 
that besides this it has the faculty of finding them in itself, 
and the disposition to approve them when it thinks of them as 
it should. 

§ 23. Ph. It seems, then, that you claim that those to whom 
these general maxims are proposed for the first time learn 
nothing which is entirely new to them. But it is clear that 
they learn first the names, then the truths, and even the ideas 
upon which these truths rest. 

Th. The question here is not of names, which are in some 
sense arbitrary, while ideas and truths are natural. But, with 
respect to these ideas and truths, you attribute to us, sir, a 
doctrine which we have strongly repudiated ; for I agree that 
we learn ideas and innate truths either in considering their 
source, or in verifying them through experience. Thus I do 
not make the supposition which you aver, as if, in the case of 
which you speak, we learned nothing new. And I cannot 
admit this proposition : all that one learns is not innate. The 
truths of numbers are in us, and we are not left to learn them, 
either by drawing them from their source when we learn them 
through demonstrative proof (which shows that they are in- 
nate), or by testing them in examples, as do ordinary arithme- 
ticians, who, in default of a knowledge of the proofs, learn 
their rules only by tradition, and, at most, before teaching 
them, justify them by experience, which they continue as far 
as they think expedient. And sometimes even a very skilful 
mathematician, not knowing the source of another's discovery, 
is obliged to content himself with this method of induction in 
examining it ; as did a celebrated writer at Paris, when I was 
there, who continued a tolerably long time the examination of 
my arithmetical tetragonism, comparing it with the numbers 
of Ludolphe, 1 believing he had found therein some error ; and 
he had reason to doubt until some one communicated to him 
the demonstration, which for us dispenses with these tests, 
which could always continue without ever being perfectly 
certain. And it is this very thing, namely, the imperfection 
of inductions, which may yet be verified by instances of expe- 
rience. For there are progressions in which one can go very 

1 John Job Ludolphe, 1649-1711: his Tetragonometria Tabularia, Frank- 
fort, 1690.— Tr. 



76 LEIBNITZ'S CRITIQUE OE LOCKE [bk. i 

far before noticing the changes and the laws that are found 
there. 

Ph. But is it not possible that not only the terms or words 
which we use, but even the ideas, come to us from without ? 

Th. It would then be necessary that we should be ourselves 
outside of ourselves, for the intellectual or reflective ideas are 
derived from our mind ; and I should much like to know how 
we could have the idea of being if we were not beings our- 
selves, and did not thus find being in ourselves. 

Ph. But what do you say, sir, to this challenge of one of my 
friends ? If any one, says he, can find a proposition whose 
ideas are innate, that he can name to me, he would do me a 
very great favor. 

Th. I would name the propositions of arithmetic and geome- 
try, which are all of this nature ; and, as regards necessary 
truths, no others could be found. 

§ 25. Ph. That will appear strange to most people. Can it 
be said that the most difficult and the most profound sciences 
are innate ? 

Th. Their actual knowledge is not, but much that may be 
called virtual knowledge is innate, as the figure traced by 
the veins of the marble is in the marble, before one discovers 
them in working. 

Ph. But is it possible that children, while receiving notions 
that come to them from without, and giving them their con- 
sent, may have no knowledge of those which you suppose to 
be inborn with them, and to make, as it were, a part of their 
mind, in which they are, you say, imprinted in ineffaceable 
characters in order to serve as a foundation ? If that were so, 
nature would have taken trouble for nothing, or, at least, she 
would have badly engraved their characters, since they cannot 
be perceived by the eyes which see very well other things. 

Tli. The apperception of that which is in us depends upon 
attention and order. ISTow, not only is it possible, but it is also 
proper, that children give more attention to the ideas of the 
senses, because the attention is regulated by the need. The 
outcome, however, shows in the sequel that nature has not 
uselessly given herself the trouble of impressing upon us in- 
nate knowledge, since without it there would be no means of 
attaining actual knowledge of the truths necessary in the 



ch. i] ON HUMAN UNDERSTANDING 77 

demonstrative sciences, and the reasons of facts ; and we 
should possess nothing above the beasts. 

§ 26. Ph. If there are innate truths, does it not necessarily 
follow that the external doctrine only stirs up here what is in 
us ? I conclude that a consent sufficiently general among men 
is an indication, and not a demonstration, of an innate princi- 
ple ; but that the exact and decisive proof of these principles 
consists in showing that their certitude comes only from what 
is in us. To reply further to what you say against the general 
approbation which is given to the two great speculative prin- 
ciples, which are, nevertheless, the best established, I may say 
to you that even if they were not known they would not cease 
to be innate, because they are recognized as soon as heard ; 
but I will add further that at bottom everybody knows them, 
and makes use at every moment of the principle of contradic- 
tion (for example) without considering it distinctly ; and 
there is no barbarian who, in an affair of any moment, is not 
offended by the conduct of a liar who contradicts himself. 
Thus, these maxims are employed without an express consid- 
eration of them. And in nearly the same way we have virtu- 
ally in the mind the propositions suppressed in enthymemes, 
which are set aside not only externally, but further in our . 
thought. 

§ 5. Ph. [What you say of this virtual knowledge and of 
these internal suppressions surprises me] ; for to say that 
there are truths imprinted upon the soul which it does not 
perceive is, it seems to me, a veritable contradiction. 

Th. [If you are thus prejudiced, I am not astonished that 
you reject innate knowledge. But I am astonished that the 
thought has not occurred to you that we have an infinite amount 
of knowledge of which we are not always conscious, not even 
when we need it. It is for the memory to preserve this, and 
for the reminiscence to represent it to us, as it often, but not 
always, does at need. That is very well called remembrance 
(subvenire), for reminiscence needs some aid. And it must 
certainly be that in this multiplicity of our knowledge we are 
determined by something to renew one part rather than another, 
since it is impossible to think distinctly and at once of every- 
thing we know.] 

Ph. In that I believe you are right ; and this too general 



78 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

affirmation, that we always perceive all the truths which are 
in our soul, escaped me without my having given it sufficient 
attention. But you will have a little more trouble in reply- 
ing to what I am going to show you. That is, that if you can 
say of some particular proposition that it is innate, you could 
maintain by the same reasoning that all propositions which 
are reasonable, and which the mind could always regard as 
such, are already impressed upon the soul. 

Th. I agree with you in regard to pure ideas, which I oppose 
to the phantoms of the senses, and in regard to necessary 
truths, or those of the reason, which I oppose to truths of 
fact. In this sense it must be said that all arithmetic and all 
geometry are innate, and are in us virtually, so that we can 
find them there if we consider attentively and set in order 
what we already have in the mind, without making use of any 
truth learned through experience or through the tradition of 
another, as Plato has shown in a dialogue l in which he intro- 
duces Socrates leading a child to abstract truths by questions 
alone without giving him any information. We can then 
make for ourselves these sciences in our study, and even with 
closed eyes, without learning through sight or even through 
touch the truths which we need; although it is true that we 
would not consider the ideas in question if we had never seen 
or touched anything. For through an admirable economy of 
nature we cannot have abstract thoughts which have no need 
whatever of anything sensible, when that would only be of 
such a character as are the forms of the letters and the sounds, 
although there is no necessary connection between such arbi- 
trary characters and such thoughts. And if the sensible out- 
lines were not requisite, the pre-established harmony between 
soul and body, of which I shall have occasion to speak more 
fully, would have no place. But that does not prevent the 
mind from taking necessary ideas from itself. You see also 
sometimes how it can go far without any aid, by a logic and 
arithmetic purely natural, as that Swedish youth who, in culti- 
vating his own (mind), went so far as to make great calcula- 
tions immediately in his head without having learned the 
common method of computation, or even to read and write, if 
I remember correctly what has been told me of him. It is 
1 Meno, 82 sq. — Tk. 



ch. i] ON HUMAN UNDERSTANDING 79 

true that he cannot Avork out intricate problems, such as those 
which demand the extraction of roots. But that does not at 
all prevent him from being able still to draw them from its 
depths by some new turn of mind. Thus that proves only 
that there are degrees in the difficulty of perceiving what is in 
us. There are innate principles which are common and very 
easy to all ; there are theorems which are discovered likewise 
at once, and which compose the natural sciences, which are 
more understood in one case than in another. Finally, in a 
larger sense, which it is well to employ in order to have notions 
more comprehensive and more determinate, all truths which 
can be drawn from primitive innate knowledge can still be 
called innate, because the mind can draw them from its own 
depths, although often it would not be an easy thing so to do. 
But, if any one gives another meaning to the terms, I do not 
wish to dispute about words. 

Ph. [I have agreed with you that we can have in the soul 
what we do not perceive there, for we do not always remem- 
ber at once all that we know, but it must be always what we 
have learned or have known in former times expressly. Thus] 
if we can say that a thing is in the soul, although the soul 
has not yet known it, this can only be because it has the 
capacity or faculty of knowing it. 

vT7i. [Why could not this have still another cause, such as 
the soul's being able to have this thing within it without its 
being perceived ? for since an acquired knowledge can be con- 
cealed therein by the memory, as you admit, why could not 
nature have also concealed therein some original knowledge ? 
Must everything that is natural to a substance which knows 
itself be known by it actually at once ? Cannot and must not 
this substance (such as our soul) have many properties and 
affections which it is impossible to consider all at once and all 
together ? It was the opinion of the Plafconists that all our 
knowledge was reminiscence, and that thus the truths which 
the soul has brought with the birth of the man, and which 
are called innate, must be the remains of an express anterior 
knowledge. But this opinion has no foundation ; and it is 
easy to believe that the soul must already Have innate knowl- 
edge in the precedent state (if there were any pre-existence), 
however -remote it might be, entirely as here : it would then 



80 LEIBNITZ'S CRITIQUE OE LOCKE" [bk. i 

have to come also from another precedent state, or 1 it would 
be finally innate, or at least concreate ; or else it would be 
needful to go to infinity and to make souls eternal, in which 
case this knowledge would be innate in fact, because it would 
never have commenced in the soul ; and if any one claimed 
that each anterior state has had something from another more 
anterior, which it has not left to the succeeding, the reply will 
be made that it is manifest that certain evident truths must 
have been in all these states ; and in whatever manner it may 
be taken, it is always clear in all states of the soul that neces- 
sary truths are innate, and are proved by what is within, it 
not being possible to establish them through experience, as we 
establish truths of fact. Why should it be necessary also 
that we could have no possession in the soul of which we had 
never made use ? And is it the same thing to have a thing 
without using it as to have only the faculty of acquiring it ? 
If that were so, we should never possess anything but the 
things which we enjoy ; instead of which, we know that, be- 
sides the faculty and the object, some disposition in the fac- 
ulty or in the object, or in both, is often necessary, that the 
faculty may exercise itself upon the object.] 

Ph. Taking it in that way, we could say that there are 
truths written in the soul which the soul has, however, never 
known, and which, indeed, it will never know. This appears 
to me strange. 

Th. [I see there no absurdity, although in that case you 
could not be assured that there are such truths. For things 
more exalted than those which we can know in this present 
course of life may be developed some time in our souls, when 
they are in another state.] 

Ph. But suppose there are truths which could be imprinted 
upon the understanding without its perceiving them ; I do 
not see how, in relation to their origin, they could differ from 
the truths which it is only capable of knowing. 

Th. The mind is not only capable of knowing them, but 
further of finding them in itself ; and, if it had only the sim- 
ple capacity of receiving knowledge, or the passive power there- 
for, as indeterminate as that which the wax has for receiving 
figures and the blank tablet for receiving letters, it would not 

1 The reading of Gerhardt and Erdmann ; Jacques has " oh," where. — Tr. 



ch. i] ON HUMAN UNDERSTANDING 81 

be the source of necessary truths, as I have just shown that it 
is ; for it is incontestable that the senses do not suffice to 
show their necessity, and that thus the mind has a disposition 
(active as well as passive) to draw them itself from its own 
depths ; although the senses are necessary to give it the occa- 
sion and attention for this, and to carry it to some rather than 
to others. You see, then, sir, that these elsewhere very clever 
persons who are of another opinion appear not to have thought 
enough upon the consequences of the difference which there is 
between necessary or eternal truths and the truths of experi- 
ence, as I have already observed, and as all our discussion 
shows. The original proof of the necessary truths comes 
from the understanding alone, and the other truths come from 
experience or from the observation of the senses. Our mind 
is capable. of knowing both; but it is the source of the former, 
and, whatever number of particular experiences we may have 
of a universal truth, we could not be assured of it forever by 
induction without knowing its necessity through the reason. 

Ph. But is it not true that if the words, to be in the under- 
standing, involve something positive, they signify to be per- 
ceived and comprehended by the understanding ? 

Th. They signify to us wholly another thing. It is enough 
that what is in the understanding can be found there, and that 
the sources or original proofs of the truths which are in ques- 
tion are only in the understanding; the senses can hint at, 
justify, and confirm these truths, but cannot demonstrate their 
infallible and perpetual certainty. 

§ 11. Ph. Nevertheless, all those who will take the trouble 
to reflect with a little attention upon the operations of the 
understanding will find that this consent, which the mind gives 
without difficulty to certain truths, depends upon the faculty 
of the human mind. 

Th. Very well. But it is this particular relation of the 
human mind to these truths which renders the exercise of the 
faculty easy and natural in respect to them, and which causes 
them to be called innate. It is not, then, a naked faculty 
which consists in the mere possibility of understanding them ; 
it is a disposition, an aptitude, a preformation, which determines 
our soul and which makes it possible for them to be derived 
from it. Just as there is the difference between the figures 

G 



82 LEIBNITZ'S CRITIQUE OE LOCKE [bk. i 

which are given to the stone or the marble- indifferently, and 
between those which its veins already indicate, or are disposed 
to indicate, if the workman profits by them. 

Ph. But is it not true that the truths are subsequent to the 
ideas of which they are born ? Now, the ideas come from 
the senses. 

Th. The intellectual ideas, which are the source of neces- 
sary truths, do not come from the senses ; and you admit that 
there are some ideas which are due to the reflection of the 
mind upon itself. For the rest, it is true that the express 
knowledge of truths is subsequent {tempore vel natura) to the 
express knowledge of ideas ; as the nature of truths depends 
upon the nature of ideas, before we expressly form one or the 
other, and the truths, into which enter ideas which come from 
the senses, depend upon the senses, at least in part. But the 
ideas which come from the senses are confused, and the truths 
which depend upon them are likewise confused, at least in 
part; while the intellectual ideas, and the truths dependent 
upon them, are distinct, and neither the one nor the other 
have their origin in the senses, although it may be true that 
we would never think of them without the senses. 

Ph. But, in your view, numbers are intellectual ideas, and 
yet it is found that the difficulty therein depends upon the 
express formation of the ideas ; for example, a man knows 
that 18 and 19 equal 37 with the same evidence that he knows 
that 1 and 2 equal 3 ; but a child does not know the first propo- 
sition so soon as the second, a condition arising from the fact 
that he has not formed the ideas as soon as the words. 

Th. I can agree with you that often the difficulty in the 
express formation of truths depends upon that in the express 
formation of ideas. Yet I believe that in your example the 
question concerns the use of ideas already formed. For those 
who have learned to count as far as 10, and the method of 
passing farther on by a certain repetition of tens, understand 
without difficulty what are 18, 19, 37 ; viz., 1, 2, or 3 times 10 
with 8, or 9, or 7 ; but, in order to draw from it that 18 plus 
19 make 37, more attention is necessary than to know that 2 
plus 1 are 3, which at bottom is only the definition of 3. 

§ 18. Ph. Furnishing propositions in which you infallibly 
acquiesce as soon as you hear them is not a privilege attached 



cit. i] ON HUMAN UNDERSTANDING 83 

to the numbers or to the ideas, which you call intellectual. 
You meet these in physics and in all the other sciences, and 
the senses even furnish them. For example, this proposition : 
two bodies cannot be in the same place at the same time, is a 
truth of which you are not otherwise convinced than of the 
following maxims : It is impossible for a thing to be and not 
to be in the same time ; white is not red ; the square is not a 
circle; yellowness is not sweetness. 

Th. There is a difference between these propositions. The 
first, which declares the impenetrability of bodies, needs proof. 
All those who believe in true and strictly formed condensa- 
tion and rarefaction, as the Peripatetics and the late Chevalier 
Digby, 1 reject it, in fact ; without speaking of the Christians 
who believe, for the most part, that the contrary view — 
namely, the penetration of space — is possible to God. But the 
other propositions are identical, or very nearly so, and identi- 
cal or immediate propositions do not admit of proof. Those 
who look upon the senses as furnishing them, as that one who 
says that yellowness is not sweetness, have not applied the 
general identical maxim to particular cases. 

Ph. Every proposition composed of two different ideas, of 
which one is the denial of the other — for example, that the 
square is not a circle, that to be yellow is not to be sweet — 
will be as certainly received as indubitable, as soon as its 
terms are understood, as this general maxim : It is impossible 
for a thing to be and not to be in the same time. 

Th. That is, the one (namely, the general maxim) is the 
principle, and the other (that is to say, the negation of one 
idea by another opposed to it) is its application. 

Ph. It seems to me rather that the maxim depends upon 
this negation, which is its ground; and that it is, besides, 
much easier to understand that what is the same thing is not 
different, than the maxim which rejects the contradictions. 
Now, according to this statement, it will be necessary for you 
to admit as innate truths an infinite number of propositions of 
this kind which deny one idea by another without speaking 

1 Sir Kenelm Digby, 1603-1665, an eminent English physical philosopher, 
who lived for a time in France, where he enjoyed the friendship of Descartes 
and other learned men, and wrote his Treatise on the Nature of Bodies and 
other works. — Tr. 



84 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

of other truths. Add to this, that a proposition cannot be 
innate unless the ideas of which it is composed are innate ; 
it will be necessary to suppose that all the ideas which we 
have of colors, sounds, tastes, figures, etc., are innate. 

Th. I do not well see how this : what is the same thing is 
not different, is the origin of the principle of contradiction, 
and easier ; for it appears to me that you give yourself more 
freedom in advancing that A is not B than in saying that A is 
not non-A. And the reason that prevents A from being B is 
that B includes non-A. For the rest this proposition : the 
sweet is not the bitter, is not innate, according to the sense 
which we have given to the term innate truth. For the sen- 
sations of sweet and bitter come from the external senses. 
Thus it is a mixed conclusion (Jiybrida conclusio), where the 
axiom is applied to a sensible truth. But as regards this 
proposition : the square is not a circle, you can affirm that it 
is innate, for, in considering it, you make a subsumption or 
application of the principle of contradiction to what the un- 
derstanding itself furnishes as soon as you are conscious of 
innate thoughts. 

Th. Not at all, for the thoughts are acts, and the knowledge 
or the truths, in so far as they are within us, even when we 
do not think of them, are habitudes or dispositions ; and we 
are well acquainted with things of which we think but little. 

Ph. It is very difficult to conceive that a truth may be in 
the mind if the mind has never thought of that truth. 

Th. It is as if some one said it is difficult to conceive that 
there are veins in the marble before we have discovered them. 
This objection seems also to approach a little too much the 
begging of the question. 1 All those who admit innate truths, 
without grounding them in the Platonic reminiscence, admit 
some of which they have not yet thought. Besides, this 
reasoning proves too much; for, if truths are thoughts, we 
shall be deprived not only of the truths of which we have 
never thought, but also of those of which we have thought, 
and of which we no longer actually think ; and if truths are 
not thoughts, but habits and aptitudes, natural or acquired, 
nothing prevents there being in tis some of which we have 
never thought, nor will ever think. 

1 Petitio principii. — Tr. 



ch. n] ON HUMAN UNDERSTANDING 85 

§ 27. Ph. If general maxims were innate, they would appear 
more vividly in the mind of certain persons where, however, 
we see no trace of them ; I may mention children, idiots, and 
savages, 1 for of all men these are they who have the mind 
less altered and corrupted by custom and by the impress of 
extraneous opinions. 

Th. I believe we must reason here very differently. Innate 
maxims appear only through the attention which is given to 
them ; but these persons have little of it, or have it for 
entirely different things. Their thoughts are mostly confined 
to the needs of the body ; and it is reasonable that pure and 
detached thoughts be the reward of cares more noble. It is 
true that children and savages have the mind less altered by 
customs, but they also have it exalted by the teaching which 
gives attention. It would not be very just that the brightest 
lights should shine better in minds which less deserve them, 
and which are enveloped in thicker clouds. I would not then 
have one give too much honor to ignorance and barbarism 
when one is as learned and as clever as you are, Philalethes, 
as well as your excellent author ; that would be lowering the 
gifts of God. Some one will say that the more ignorant we 
are, the more we approach the advantage of a block of marble 
or of a piece of wood, which are infallible and sinless. But, 
unfortunately, it is not by ignorance that we approach this 
advantage ; and, as far as we are capable of knowledge, we 
sin in neglecting to acquire it, and we shall fail so much the 
more easily as we are less instructed. 



CHAPTER II 

NO INNATE PRACTICAL PRINCIPLES 

§ 1. Ph. Ethics is a demonstrative science, and yet it has 
no innate principles. And, indeed, it would be very difficult 
to produce a rule of ethics of a nature to be settled by an 
assent as general and as prompt as this maxim : Wliatev er 
is, is. 

1 For an excellent exposition of the content of the term savage, cf. Andrew 
Lang, Myth, Ritual, and Religion, Vol. 1, p. 31, and note; also chap. 3, pp. 
46 sq., London: Longmans, Green, & Co., 1887. — Tr. 



86 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

Th. It is absolutely impossible that there be truths of 
reason as evident as those which are identical or immediate. 
And, although you can truly say that ethics has principles 
which are not demonstrable, and that one of the first and most 
practical is, that we ought to pursue joy and avoid sorrow, it 
is needful to add that this is not a truth which is known 
purely by reason, since it is based upon internal experience, or 
upon confused knowledge, for we do not feel what joy or 
sadness is. 

Ph. It is only through processes of reasoning, through lan- 
guage, and through some mental application, that you can be 
assured of practical truths. 

Th. Though that were so, they would not be less innate. 
However, the maxim I just adduced appears of another na- 
ture j it is not known by the reason, but, so to speak, by an 
instinct. It is an innate principle, but it does not form a 
part of the natural light, for it is not known luminously. But 
this principle admitted, you can draw from it scientific con- 
sequences, and I commend most heartily what you just said of 
ethics as a demonstrative science. Let us note also that it 
teaches truths so evident that thieves, pirates, and bandits are 
forced to observe them among themselves. 

§ 2. Ph. But bandits keep the rules of justice among them- 
selves without considering them as innate principles. 

Tit. What matters it ? Does the world concern itself about 
questions of theory ? 

Ph. They observe the maxims of justice only as convenient 
rules, the practice of which is absolutely necessary to the con- 
servation of their society. 

Th. [Very well. You could say nothing better in general in 
respect to all men. And thus it is that these laws are written 
in the soul, namely, as the consequences of our preservation 
and of our true welfare. Do you imagine that we suppose 
that truths are in the understanding as independent the one of 
the other as the edicts of the praetor were on his placard or 
album ? I put aside here the instinct which prompts man to 
love man, of which I shall presently speak, for now I wish to 
speak only of truths in so far as they are known by the reason. 
I admit, also, that certain rules of justice cannot be demon- 
strated, in all their extent and perfection, without supposing 



ch. nj ON HUMAN UNDERSTANDING S7 

the existence of God and the immortality of the soul, and 
these, where the instinct of humanity does not impel us, are 
written in the soul only as other derivative truths.] Those, 
however, who base justice only upon the necessities of this life 
and upon the need they have of it, rather than upon the pleas- 
ure they ought to take in it, which is the greatest when God 
is its ground, are liable to resemble a little the society of 
bandits. 

Sit spes fallencli, miscebunt sacra profanis. 1 

§ 3. Ph. I agree with you that nature has put in all men 
the desire for happiness and a strong aversion to misery. 
These are the truly innate practical principles, and principles 
which, according to the purpose of every practical principle, 
have a continual influence upon all our actions. But they are 
inclinations of the soul toward the good, and not impressions 2 
of some truth which is written in our understanding. 

Th. [I am delighted, sir, to see that you admit in effect 
innate truths, as I shall presently say. This principle agrees 
sufficiently with that which I just indicated, which prompts 
us to seek joy and shun sorrow. For felicity is only a last- 
ing joy. Our inclination, however, does not tend to felicity 
proper, but to joy — that is to say, to the present ; it is the 
reason which prompts to future and enduring welfare. Now, 
the inclination, expressed by the understanding, passes into a 
precept or practical truth ; and if the inclination is innate, the 
truth is innate also, there being nothing in the soul which 
may not be expressed in the understanding, but not always by 
a consideration actually distinct, as I have sufficiently shown. 
The instincts also are not always practical ; there are some 
which contain theoretical truths, and such are the internal 
principles of the sciences and of reasoning, when, without rec- 
ognizing the reason in them, we employ them by a natural 
instinct. And in this sense you cannot dispense with the 
recognition of innate principles, even though you might be 
willing to deny that derivative truths are innate. But this 
would be a question of name merely after the explanation I 

1 Of. Hor. Epist., 1, 16, 54. Horace has "rniscebis." — Tr. 

2 Erdmann and Jacques read, " des imperfections de quelque verite." Ger- 
hardt reads, "des impressions cle quelque verite." Locke has, "impressions 
of truth." Book I., chap. 3, § 3. Vol. 1, p. 158, line 5, Bohn's edition.— Tr. 



88 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

have given of what I call innate. And if any one desires to , 
give this appellation only to the truths which are received at 
first by instinct, I shall not contest the point with him.] 

Ph. That is well. But if there were in our soul certain 
characters imprinted there by nature, like so many principles 
of knowledge, we could only perceive them acting in us, as we 
feel the influence of the two principles which are constantly 
active in us — namely, the desire of happiness and the fear of 
misery. 

Th. [There are principles of knowledge which influence us 
as constantly in our reasoning processes as these practical prin- 
ciples influence us in our volitions ; for example, everybody 
employs the rules of deduction by a natural logic without 
being aware of it. 

§ 4. Ph. The rules of Morality need to be proved ; they are 
then not innate, like that rule which is the source of the vir- 
tues which concern society : Do to another only what you would 
have him do to yourself. 

Th. You always make me the objection which I have al- 
ready refuted. I agree with you that there are moral rules 
which are not innate principles ; but that does not prevent them 
from being innate truths, for a derivative truth will be innate, 
supposing that we can draw it from our mind. But there are 
innate truths, which we find in us in two ways — by insight 
and by instinct. Those which I have just indicated, show by 
our ideas what natural insight accomplishes. But there are 
conclusions of natural light which are principles in relation 
to instinct. It is thus that we are prompted to acts of human- 
ity, by instinct because it pleases us, and by reason because it 
is just. There are then in us truths of instinct, which are 
innate principles, which we feel and approve, although we have 
not the proof of them which we obtain, however, when we give 
a reason for this instinct. It is thus that we make use of 
the laws of deduction conformably to a confused knowledge, 
and as by instinct, but logicians show the reason of them, as 
mathematicians also give a reason for what they do without 
thinking in walking and leaping. As for the rule which states 
that we ought to do to others only what we would have them 
do to us, it needs not only proof, but also to be proclaimed. We 
should wish too much for ourselves if we could have our own 



ch. ii] ON HUMAN UNDERSTANDING 89 

way ; shall we say then that we also owe too much to others ? 1 
You will tell me that the rule means only a just will. But 
thus this rule, very far from being adequate to serve as a 
measure, would itself need one. The true sense of the rule 
is, that the place of another is the true point of view for equi- 
table judgment when we attempt it.] 

§ 9. Ph. Bad acts are often committed without any remorse 
of conscience ; for example, when cities are carried by storm, 
the soldiers commit, without scruple, the worst acts ; some 
civilized nations have exposed their children, some Caribbees 
castrate theirs in order to fatten and eat them. Garcilasso de 
la Vega 2 reports that certain peoples of Peru took prisoners in 
order to make concubines of them, and supported the children 
up to the age of thirteen, after which they ate them, and 
treated in the same manner the mothers so soon as they no 
longer bore children. In the travels of Baumgarten 3 it is re- 
lated that there was a Santon 4 in Egypt who passed for a holy 
man, eo quod non foeminarum unquam esset ac puerorum, sed 
-tantum asellarum concubitor atque mularum. 

Th. Moral science (over and above the instincts like that 
which makes us seek joy and shun sadness) is not otherwise 
innate than is arithmetic, for it depends likewise upon demon- 
strations which internal light furnishes. And as the dem- 
onstrations do not at once leap into sight, it is no great wonder, 
if men do not perceive always and at once all that they pos- 
sess in themselves, and do not read quite readily the characters 
of the natural laiv, which God, according to St. Paul, 5 has writ- 
ten in their minds. As morality, however, is more important 
than arithmetic, God has given to man instincts which prompt 

1 This sentence is found in the texts of Erdmann and Gerhardt ; it is "want- 
ing in that of Jacques. — Tr. 

2 Garcilasso de la Vega, 1540-1616, the son of an Inca princess, and a Span- 
ish conqueror, a companion of Pizarro. His Commentaries reales was pub- 
lished in two parts, the first at Lisbon, 1609, giving an account of the native 
traditions, customs, and history previous to the Spanish conquest ; the second 
under the separate title of Historic, General del Peru, Cordova, 1617, treating 
of the Spanish conquest. The earlier and more important part of the work 
has been translated, with "learned and ingenious notes," by Clements R. 
Markham, and published in the collection of the Hakluyt Society, 2 vols., 
London : 1869, 1871. — Tr. 

3 Martin Baumgarten, 1473-1535, Travels through Egypt, Arabia, etc. In 
Churchill, O. and J. Col., Vol. 1, 1744. — Tr. 

4 Mahometan monk. — Tr. 5 Rom. 2 : 15 ; cf. 1 : 19. — Tr. 



90 LEIBNITZ'S CRITIQUE OF LOCKE [bk. 

at once and without reasoning to some portion of that which 
reason ordains ; just as we walk in obedience to the laws 
of mechanics without thinking of these laws, and as we eat, 
not only because eating is necessary for us, but further and 
much more because it gives us pleasure. But these instincts 
do not prompt to action in an invincible way ; the passions 
may resist them, prejudices may obscure them, and contrary 
customs alter them. Nevertheless, we agree most frequently 
with these instincts of conscience, and we follow them also 
when stronger impressions do not overcome them. The great- 
est and most healthy part of the human race bears them wit- 
ness. The Orientals, the Greeks and Eomans, the Bible 
and the Koran agree in respect to them; the Mahometan 
police are wont to punish the thing Baumgarten tells of, and 
it would be needful to be as brutalized as the American savage 
in order to approve their customs, full of a cruelty which sur- 
passes even that of the beasts. Yet these same savages per- 
ceive clearly what justice is on other occasions ; l and although 
there is no bad practice, perhaps, which may not be authorized 
in some respects and upon some occasions, there are few of 
them, however, which are not condemned very frequently and 
by the larger part of mankind. That which has not been at- 
tained without reason, and was not attained by reasoning alone, 
should be referred in part to the natural instincts. Custom, 
tradition, discipline, are mingled therein, but it is due to in- 
stinct (le naturel) that custom is turned more generally to the 
good side of these duties. In the same way, 2 the tradition of 
God's existence is due to instinct (le naturel). Now nature 

i Of. J. G. Schurman, The Ethical Import of Darwinism, pp. 256-260, New 
York': Charles Scribner's Sons, 1887. He states that " some gropings amid the 
general darkness incline me, at least tentatively, to the belief that, apart from 
the domestic virtues, there is no such great difference between the morals of 
Christians and the morals of savages" (p. 256). This statement is modified 
further on, pp. 258, 259, and finally takes the following form : "The fighting 
men, actual and potential, in every uncivilized community recognize the same 
rights, obligations, and duties toward one another as constitute the essence of 
civilized morality. You never find a man without a moral nature, a nature 
essentially like our own ; but the objects he includes within the scope of its 
outgoings vary" (p. 259). For the real significance of such facts, cf. Ex- 
Pres. E. G. Robinson, of Brown University, Principles and Practice of Moral- 
ity, p. 43, Boston: Silver, Burdett & Co., 1888. — Tk. 

2 Gerhardt reads, "C'est comme le naturel," etc.; Erdmann and Jacques, 
" Le naturel," etc. — Tr. 






en. ii] ON HUMAN UNDERSTANDING 91 

gives to man and also to most of the animals affectionate and 
tender feeling for those of their species. The tiger even par- 
cit cognatis masculis; 1 whence comes this bon mot of a Soman 
jurisconsult, Quia inter omnes homines natura cognationem 
constituit, unde hominum homini insicliari nefas esse. Spiders 
form almost the only exception, and these eat one another 
to this extent that the female devours the male after having 
enjoyed him. Besides this general instinct of society, which 
may be called philanthropy in man, there are some more par- 
ticular forms of it, as the affection between the male and the 
female, the love which father and mother bear toward the chil- 
dren, which the Greeks call aropyy, 2 and other similar inclina- 
tions which make this natural law, or this image of law rather, 
which, according to Roman jurisconsults, nature has taught 
the animals. But in man in particular there is found a certain 
regard for dignity, for propriety, which leads him to conceal 
the things which lower us, to be sparing of shame, to have 
repugnance for incests, to bury dead bodies, not to eat men at 
all, nor living animals. One is led further to be careful of his 
reputation, even beyond need, and of life ; to be subject to 
remorse of conscience, and to feel these laniatus et ictus, 
these tortures and torments of which Tacitus, following Plato, 
speaks ; 3 besides the fear of a future and of a supreme power 
which arises, moreover,, naturally enough. There is reality in 
all that ; but at bottom these natural impressions, whatever 
they may be, are only aids to the reason and indices of the 
plan of nature. Custom, education, tradition, reason, contrib- 
ute much, but human nature ceases not to participate therein. 
It is true that without the reason these aids would not suffice 
to give a complete certitude to morals. Finally, will you -deny 
that man is naturally led, for example, to withdraw from vile 
things, under a pretext that races are found who like to speak 
only of filth, that there are some, indeed, whose mode of life 
obliges them to handle excrements, and that there are people 
of Boutan, where those of the king pass as an aromatic ? I 
think that you are of my opinion at bottom in regard to these 
natural instincts which tend toward what is right and decent ; 

i Jut. Sat., 15, 159-160. — Tr. 

2 The reading (nom. cnopy-q) of Erdmann and Jacques. Gerhardt's reading, 
bpy'w, is evidently an error. — Tr. 3 Gorgias, 524 E ; Ann. 6, 6. — Tr. 



92 LEIBNITZ'S CRITIQUE OE LOCKE [bk. i 

although you will say, perhaps, as you have said with regard 
to the instinct which prompts to joy and felicity, that these 
impressions are not innate truths. But I have already replied 
that every feeling is the perception of a truth, and that the 
natural feeling is the (perception) of an innate truth, but very 
often confused, as are the experiences of the external senses ; 
thus you can distinguish the innate truths from the natural 
light (which contains only the distinctly knowable), as the 
genus must be distinguished from its species, since the innate 
truths comprehend both the instincts and the natural light.'] 

§ 11. Ph. A person who knew the natural limits of justice 
and injustice, and (who) would not cease confusing them with 
each other, could only be regarded as the declared enemy of 
the repose and the welfare of the society of which he is a mem- 
ber. But men confuse them every moment, consequently they 
do not know them. 

Th. [That is taking things a little too theoretically. It 
happens every day that men act contrary to their knowledge in 
concealing these (limits) from themselves when they turn the 
mind elsewhere, in order to follow their passions ; otherwise, 
we should not see people eating and drinking what they know 
must cause them sickness and even death. They would not 
neglect their business ; they would not do what entire nations 
have done in certain respects. The future and reason rarely 
make so strong an impression as the present and the senses. 
That Italian knew this well, who, before being put to torture, 
proposed to have the gallows continually in sight during the 
torments in order to resist them, and they heard him say some- 
times, " Io ti vedo," which he explained afterward when he had 
escaped. Unless you firmly resolve to look upon the true good 
and the true evil with the purpose of following or shunning 
them, you find yourself carried away, and it happens, with re- 
gard to the most important needs of this life, as it happens with 
regard to paradise and hell in the case of those, indeed, who 
believe in them the most : — 

Cantantur hsec, laudantur hsec, 

Dicuntur, audiuntur. 
Scribuntur haec, leguntur hsec, 

Et lecta negliguntur.] 



ch. ii] ON HUMAN UNDERSTANDING 93 

Ph. Every principle which you suppose innate can only be 
known by each one as just and advantageous. 

Th. [You always return to this supposition, which I have 
refuted so many times, that every innate truth is known 
always and by all.] 

§ 12. Ph. But a public permission to violate the law proves 
that this law is uot innate ; for example, the law requiring the 
love and* preservation of children was violated among the 
ancients when they permitted their exposure. 

Th. [This violation supposed, it follows only that you have 
not well read these characters of nature written in our soul, 
but sometimes obscure enough by reason of our excesses, not 
to mention that, in order to have a perfectly clear perception 
of the necessity of duties, men must see the demonstration of 
them — a condition that is rarely fulfilled. If geometry were as 
much opposed to our passions and present interests as is ethics, 
we should contest it and violate it but little less, notwith- 
standing all the demonstrations of Euclid 1 and of Archimedes, 1 
which you would call dreams and believe full of paralogisms ; 
and Joseph Scaliger, Hobbes, 2 and others, who have written 
against Euclid and Archimedes, would not find themselves in 
such a small company as at present. It was only the passion 
for glory, which these authors believed they found in the quad- 
rature of the circle and other difficult problems, which could 

1 Euclid, not to be confounded with Euclid of Megara, a pupil of Socrates, 
founder of the Megarian school, the fundamental principle of whose philosophy- 
was the union of the Eleatic idea of being with the Socratic idea of the good. 
The date of neither his birth nor death is known. Proclus, the Neo-Platonist, 
410-485 a.d., says that Euclid lived in the time of Ptolemy I., king of Egypt, 
who reigned from 323-285 b.c, and that he was younger than Plato's associates, 
but older than Eratosthenes, "276-2—196-2 B.C.," "the celebrated scholar 
whose chronological dates were adopted for the history of philosophy " (Zeller, 
Outlines, §§ 3, 66), and Archimedes, 287-212 b.c. Proclus preserves Euclid's 
reply to King Ptolemy, who asked him if there were no easier way to learn 
geometry than by studying his elements. "There is no royal road to geom- 
etry."— Tr, 

2 Thomas Hobbes, 1588-1679. The statement of his geometrical principles 
in opposition to those of Euclid is found in the Appendix to the English trans- 
lation of the Be Gorpore, which appeared about the middle of 1656, entitled 
Six Lessons to the Professors of Mathematics, one of Geometry, the other of 
Astronomy, in the University of Oxford, English Works, Vol. 7, pp. 181-356. 
For an account of the controversy in which these appeared, cf. George Croom 
Robertson, Hobbes, pp. 167-178 (Philosophical Classics). Edinburgh: William 
Blackwood & Sons, 1886. —Tr. 



91 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

blind to such a point persons of so great merit. And if others 
had the same interest, they would make use of it in much the 
same manner.] 

Ph. Every duty carries the idea of law, and a law cannot 
be known or supposed without a legislator who has prescribed 
it, or without reward and without punishment. 

Th. [There can be natural rewards and penalties without 
a legislator ; intemperance, for example, is punished by disease. 
As this, however, does not injure all at first, I admit that there 
are few precepts to which you would necessarily be bound if 
there were not a God who leaves no crime without chastise- 
ment, no good act without reward.] 

Ph. The ideas of a God and of a life to come must then also 
be innate. 

Th. [I am agreed in the sense in which I have explained 
myself.] 

Ph. But these ideas are so far from being written by nature 
in the minds of all men, that they even do not appear very clear 
and very distinct in the minds of many students, who also pro- 
fess to examine things with some accuracy ; so far are they 
from being known by every human being. 

TJi. You return again to the same proposition, which main- 
tains that what is not known is not innate, which I have, how- 
ever, refuted so many times. What is innate is not at first 
known clearly and distinctly as such; often much attention 
and method is necessary in order to its perception, the student- 
class do not always adduce it, still less every human being. 

§ 13. Ph. But if men can be ignorant of or call in question 
that which is innate, it is in vain for you to speak to us of in- 
nate principles, and to claim to show us their necessity ; very 
far from their being able to serve as our instructors in the truth 
and certitude of things, as is maintained, we shall find our- 
selves, with these principles, in the same state of uncertainty 
as if they were not in us. 

Th. You cannot call in question all the innate principles. 
You were agreed in regard to identical propositions or the 
principle of contradiction, admitting that there are incontest- 
able principles, although you would not then recognize them 
as innate ; but it does not at all follow that everything which 



ch. n] ON HUMAN UNDERSTANDING 95 

is innate and necessarily connected with these innate princi- 
ples, is also at first indubitably evident. 

Ph. No one that I know of has yet undertaken to give us an 
exact catalogue of these principles. 

Th. But has any one hitherto given us a full and exact 
catalogue of the axioms of geometry ? 

§ 15. Ph. My Lord Herbert 1 has been pleased to point out 
some of these principles, which are : 1. There is a supreme 
God. 2. He ought to be served. 3. Virtue united with piety 
is the best worship. 4. Eepentance for sin is necessary. 
5. There are penalties and rewards after this life. I agree 
that these are evident truths and of such a nature that when 
well explained a reasonable person can scarcely avoid giving 
them his consent. But our friends say that they are very far 
from being so many innate impressions, and if these five 
propositions are common notions written in our souls by the 
finger of God, there are many others which we ought also to 
put into this class. 

Th. I agree with you, sir, for I take all the necessary truths 
as innate, and I connect with them also the instincts. But, I 
agree with you, that these five propositions are not innate prin- 
ciples ; for I hold that they can and ought to be proved. 

§ 18. .Ph. In the third proposition, that virtue is the wor- 
ship most agreeable to God, it is not clear what- is meant by 
virtue. If you understand it in the sense most commonly 
given to the term, I mean that which passes as praiseworthy 
according to the different opinions which prevail in different 
countries, this proposition is so far from being evident that it 
is not even true. If you call virtue 2 the acts which are con- 
formed to the will of God, this will be almost idem per idem, 
and the proposition will teach us nothing of importance ; for 
it would mean only that God is pleased with that which is con- 
formed to his will. It is the same with the notion of sin in 
the fourth proposition. 

i Lord Edward Herbert of Cherbury, 1581-1648. His T)e Veritate, Paris, 
1624, has had considerable influence on English philosophical and religious 
thought, and is of some importance in the interxDretation of the polemic of 
Locke's Essay. — Tr. 

2 For an excellent but brief statement and discussion of the main theories of 
virtue, cf. E. G. Robinson: Principles and Practice of Morality, pp. 140- 
180.— Tk. 



96 LEIBNITZ'S CRITIQUE OE LOCKE [bk.i 

Th. I do not remember to have remarked that virtue is 
commonly taken as something which depends upon opinion; 
at least, the philosophers do not make it that. It is true that 
the name of virtue depends upon the opinion of those who 
give it to different habits or actions, according as they deem 
them good or bad and use their reason ; but all are sufficiently 
agreed as to the notion of virtue in general, although they dif- 
fer in its application. According to Aristotle 1 and several 
others, virtue is a habit of restraining the passions by the rea- 
son, and still more, simply a habit of acting according to rea- 
son. And that cannot fail to be agreeable to him who is the 
supreme and final reason of things, to whom nothing is indif- 
ferent, and the acts of rational creatures less than all others. 

§ 20. Ph. You are wont to say that the custom, the educa- 
tion, and the general opinions of those with whom you con- 
verse may obscure these principles of morality which you 
suppose innate. But if this reply is a good one, it annihilates 
the proof which you pretend to draw from universal consent. 
The reasoning of many men reduces to this : The principles 
which men of right reason admit are innate ; we and those 
of our mind are men of right reason ; consequently our princi- 
ples are innate. A pleasant method of reasoning, which goes 
straight on to infallibility ! 

Th. For myself, I make use of universal consent, not as a 
principal proof, but as a confirmatory one ; for innate truths 
taken as the natural light of reason bear their marks with 
them as does geometry, for they are wrapped up in the im- 
mediate principles which you yourselves admit as incontesta- 
ble. But I grant that it is more difficult to distinguish the 
instincts and some other natural habits from custom, although 
it may very often be possible so to do. For the rest, it appears 
to me that people who have cultivated their minds have some 
ground for attributing the use of right reason to themselves 
rather than to the barbarians, since in subduing them almost 
as easily as they do animals they show sufficiently their supe- 

1 Eth. Nic. II. 6, ad init. Of. Zeller : Outlines of the Hist, of Greek Philos., 
§ 61 ; and E. Wallace : Outlines of the Philos. of Aristotle, 3d ed., § 59, pp. 97- 
99. Cambridge : University Press, 1883. In connection with each section of 
his brief English statement and exposition, Wallace gives the Greek text of 
" the more important passages in Aristotle's writings," with references to the 
Berlin Academy edition of Aristotle. — Tr. 



ch. n] ON HUMAN UNDERSTANDING 97 

riority. But if they cannot always succeed in this, it is be- 
cause just like the animals they conceal themselves in the 
thick forests, where it is difficult to hunt them down and the 
game is not worth the candle. It is doubtless an advantage to 
have cultivated the mind, and if we may speak for barbarism 
as against culture, we shall also have the right to attack rea- 
son in favor of the animals, and to take seriously the witty 
sallies of M. Despreaux, 1 in one of his satires, where, in order 
to contest with man his prerogative over the animals, he asks, 
whether, 

The bear is afraid of the passer-by, or the passer-by of the bear ; 
And if, by decree of the shepherds of Libya, 
The lions would vacate the parks of Numidia, etc. 

We must, however, admit that there are some points in which 
the barbarians surpass us, especially as regards vigor of body ; 
and as regards the soul even we may say that in certain respects 
their practical morality is better than ours, because they have not 
the avarice of hoarding nor the ambition of ruling. And we 
may even add that association with Christians has made them 
worse in many respects. 2 They have taught them drunkenness 
(when carrying them the water of life), swearing, blasphemy, 
and other vices, which were little known to them. There is 
with us more of good and of evil than with them : a bad Euro- 
pean is worse than a savage — he refines upon evil. 3 Still, 
nothing should prevent men from uniting the advantages which 
nature gives to these peoples with those which reason gives us. 

1 Nicolas Boileau-Despreanx, 1036-1711. The passage quoted is from Sat. 8, 
62-64. The text as given by all the editions I have been able to consult, 
twelve, ranging from 1716-1873, reads thus : 

"L'ours a peur du passant, ou le passant de Tours; 
Et si, sur un e'dit des patres de Nubie, 
Les lions de Barca videraient la Lybie;" etc. 
Lines 63 and 64 of the text, as given by Leibnitz, editions of Gerhardt and 
Erdmann, Jacques modernizing the spelling and correcting the misplacement 
of " de " and " des " in line 63, read thus: 

"Et si par un e'dit de pastres des Lybie 
Les Lions vuideroient les pares de Numidie," etc. 
It seems evident that Leibnitz misquoted the lines. — Tr. 

2 Compare J. G. Schurman : The Ethical Import of Darwinism, pp. 256-260 
as above. — Tr. 

3 The French is : " il rafine sur le mal." — Tr. 



98 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

Ph. But what reply do you make, sir, to this dilemma of 
one of my friends ? I would be pleased, he says, to have the 
advocates of innate ideas tell me whether these principles can 
or cannot be effaced by education and custom. If they cannot 
be effaced we ought to find them in all men, and they should 
clearly appear in the mind of each particular man. If they 
can be altered by extraneous ideas, they ought to appear more 
distinctly and with more lustre the nearer they are to their 
source. I mean in children or illiterate people, upon whom 
extraneous opinions have made less impression. Let them 
take which side they please, they will clearly see, he says, that 
it is contradicted by indubitable facts and by continual expe- 
rience. 

Th. I am astonished that your clever friend has confounded 
obscurity with effacement, as some in your party confound non- 
being with no7i-ap}oearance. Innate ideas and truths cannot 
be effaced, but they are obscured in all men (as they are now) 
by their inclination toward the needs of the body, and oftener 
still by the occurrence of bad customs. These characteristics 
of the internal light would always be shining in the under- 
standing and would give fervor to the will, if the confused 
perceptions of sense did not engross our attention. It is the 
struggle of which Holy Scripture no less than ancient and 
modern philosophy speaks. 

Ph. Thus, then, we find ourselves in darkness as thick and 
in uncertainty as great as if there were no such light. 

Th. God forbid; we should have neither science nor law, 
nay, not even reason. 

§ 21, 22, etc. Ph. I hope that you will at least admit the 
force of prejudice, which often causes that to pass as natural 
which has come from the bad instruction to which children 
have been exposed, and the bad customs which education and 
association have given them. 

Th. I admit that the excellent author whom you follow says 
some very fine things upon that subject, and which have their 
value if they are taken as they should be ; but I do not believe 
that they are opposed to the doctrine properly understood of 
nature or of innate truths. And I am confident that he will not 
extend his remarks too far ; for I am equally persuaded that 
a great many opinions pass for truths which are only the effects 



ch. n] ON HUMAN UNDERSTANDING 99 



of custom and of credulity, and that there are many such opin- 
ions, too, which certain philosophers would fain account for as 
matters of prejudice, which are, however, grounded in right 
reason and in nature. There is as much or more ground for de- 
fending ourselves from those who through ambition oftenest 
make pretensions to innovation, than for challenging ancient im- 
pressions. And after having meditated sufficiently upon ancient 
and modern thought, I have found that the majority of the re- 
ceived doctrines may bear a good sense. So that I wish that 
sensible men would seek to satisfy their ambition by occupy- 
ing themselves rather in building and advancing than in retro- 
grading and destroying. And I desire them to resemble the 
Romans who constructed beautiful public works, rather than 
that Vandal king 1 whom his mother charged to seek the de- 
struction of these grand structures, since he could not hope for 
the glory of equalling them. 

Ph. The aim of the clever class who have contended against 
innate truths has been to prevent men from handing round 
their prejudices and seeking to cover their idleness beneath 
this fair name. 

Th. We are agreed upon this point, for, very far from ap- 
proving that doubtful principles be received, I would, for my- 
self, seek even the demonstration of the axioms of Euclid, as 
some ancients also have done. And when you ask the means 
of knowing and examining innate principles, I reply, following 
what I said above, that with the exception of the instincts 
whose reason is unknown, you must try to reduce them to first 
principles, that is to say, to axioms identical or immediate by 
means of definitions, which are nothing else than a distinct 
exposition of ideas. I do not doubt even but that your friends, 
who have hitherto been opposed to innate truths, would ap- 
prove this method, which appears consonant with their princi- 
pal aim. 

1 Ckrocus, who with the Sueves and Alans is said to have passed over the 
Rhine near Mayence, and following the evil counsel of his mother, to have 
ravaged in the most frightful manner in Germany as in Gaul. The story is 
given in the Chronicle of Idatius, chap. 62. Cf. Bouquet, Eerum Gall, et 
Franc. Scriptores, Tom. 2, p. 464. — Tr. 



100 LEIBNITZ'S CRITIQUE OF LOCKE 



CHAPTER III 

OTHER CONSIDERATIONS TOUCHING INNATE PRINCIPLES, BOTH 
SPECULATIVE AND PRACTICAL 

§ 3. Ph. You wish to reduce truths to first principles, and 
I grant you that if there is any such principle, it is without 
gainsaying this ; it is impossible for a thing to be and not to 
be at the same time. It appears, however, difficult to maintain 
its innate character, since you must be convinced at the same 
time that the ideas of impossibility and identity are innate. 

Th. It is quite necessary that those who favor innate truths 
maintain and be convinced that these ideas are also innate, and 
I admit that I am of their opinion. The ideas of being, of 
possibility of identity, are so completely innate that they 
enter into all our thoughts and reasonings, and I regard them 
as essential to our mind ; but I have already said that we do 
not always pay them particular attention and that we discern 
them only with time. I have said hitherto that we are, so to 
speak, innate unto ourselves, and since we are beings, the being 
we is innate ; and the knowledge of being is wrapped up in 
that knowledge which we have of ourselves. There is some- 
thing similar in the case of other general notions. 

§ 4. Ph. If the idea of identity is natural, and consequently 
so evident and so present to the mind that we ought to recog- 
nize it from the cradle, I would be pleased to have a child of 
seven years, and even a man of seventy, tell me whether a man 
who is a creature consisting of body and soul, is the same (man) 
when his body is changed, and whether, metempsychosis sup- 
posed, Euphorbus would be the same as Pythagoras. 

Th. I have stated sufficiently that what is natural to us is not 
known to us as such from the cradle; and even an idea may be 
known to us without our being able to decide at once all ques- 
tions which can be formed thereupon. It is as if some one main- 
tained that a child cannot have a knowledge of the square and 
its diagonal, because he will have difficulty in recognizing that 
the diagonal is incommensurable with the side of the square. 
As for the question itself, it appears to me demonstratively 



en. in] ON HUMAN UNDERSTANDING 101 

solved by the doctrine of Monads, which I have elsewhere 1 
shown in its true light, and we shall speak more fully of this 
matter in the sequel. 

1 Cf. the Essay, without title, Gerhardt, 4, 427 sq., written at the beginning 
of 1686, and referred to as " un petit discours de Metaphysique," in Leibnitz's 
letter, Feb. 1-11, 1686, to the Landgraf Ernst von Hessen-Rheinfels, G. 2, 11. 
This ' Discours,' regarded by Leibnitz as the beginning of his philosophy, con- 
tains a summary, centring about the idea of the individual substance, of all 
his previous philosophical speculation. He gained this idea, and with it a 
seemingly satisfactory solution of the principal philosophical problem, at the 
end of 1685 or the beginning of 1686. For this idea, still in process of devel- 
opment, possessing the elements of force and individuality, but lacking those 
of continuity and perceptive activity evolved between 1686 and 1697, Leibnitz, 
in 1697, when the idea possessed all the elements essential to its completeness 
in his system, appropriated the term " monad." This term he borrowed, not 
from Giordano Bruno, 1548-1600, who used it in a similar though not precisely 
the same sense, but from Francois Mercure Van Helmout, 1618-1699. So far 
as known, the term "monad" is first mentioned in the letter to Fardella, 
Sept. 3-13, 1696, first published by Foucher de Careil, Nouv. lettr. et opusc. de 
Leibniz, p. 328, Paris, 1857. The doctrine in substauce till 1697, and thereafter 
in name, Leibnitz frequently set forth with increasing clearness and complete- 
ness in letters to his numerous correspondents, and in the " Acta Eruditorum " 
and the " Journal des Savans." Reference may be made, among others, to the 
following: Correspondence with Antoine Arnauld, 1612-1694, especially the 
letter dated Venice, Mar. 23, 1690, G. 2, 134; Erdmann, 107; Jacques, 1, 443; 
trans., Appendix, ; the two systematic elaborations of his system of 

the year 1695, the mathematical in the Specimen dynamicum p>ro admirandis 
naturse leyibus, etc., Gerhardt, Leibniz, math. Schrift., 6, 234 sq.; the meta- 
physical in the Systeme nouveau de la nature, etc., G. 4, 477; E. 124; trans., 
Appendix, ; De ipsa natura, etc., 1698, espec. §§ 11, 12, G. 4, 504 ; E. 154 ; 

J. 1, 455 (in French) ; trans., Appendix, ; Response (Replique, Erdmann) 

aux reflexions continues dans la seconde edition du Dictionnaire Critique de 
M. Bayle, etc., 1702, G. 4, 554; E. 183; trans., Appendix, ; Letters to 

Rud. Christ. Wagner De vi activa corporis, June 4, 1710, G. 7, 528; E. 465; 
trans., Duncan, Philos. Wks. of Leibnitz, 190; to Bierling, Aug. 12, 1711, 
G. 7, 500; E. 677; Principes de la nature, etc., c. 1714, G. 6, 598; E. 714; 
trans., Duncan, 209; La Monadoloc/ie, 1714, G. 6, 607; E. 705; trans., Duncan, 
218, F. H. Hedge, "Jour. Spec. Philos.," Vol. 1, p. 129; Letters to Des Bosses, 
G. 2, 285 sq., passim, which present most penetrating discussions of Leibnitz's 
metaphysic and form the most ample commentary on the Monadoloc/ie ; to De 
Voider, 1643-1709, G. 2, 139 sq., passim, proving the intimate connection of 
Leibnitz's dynamic and metaphysic; to Bour°uet, Dec. 1714, G. 3, 575; E. 720; 
to Remond (de Montmort, E. 724), Feb. 11, 1715, §§ 3, 4, G. 3, 635; to Dangi- 
court, Sept. 1716, Dutens, Leibnit. opera omnia, 3, 499; E. 745. Of the pieces 
cited the most important are : The Letter to Arnauld, Mar. 23, 1690, the Systeme 
nouveau, the De ipsa natura, the Principes de la nature, and the Monado- 
logie. As Leibnitz was occupied, more or less as circumstances permitted, 
with the composition and revision of his ' New Essays,' from 1700, when Coste's 
translation of Locke's 'Essay' appeared, to 1709 and perhaps later (vid. ante, 
p. 9 and note), possibly even as late as 1714 or 1716, the relative date of com- 
position of the several pieces here cited to that of the ' New Essays ' can easily 



102 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

§ 6. Ph. [I see very well that to you I should object in vain 
that the axiom which declares that the whole is greater than its 
part is not innate, nnder pretext that the ideas of whole and 
part are relative, dependent upon those of number and exten- 
sion ; since you would apparently maintain that there are ideas 
conditionally innate, and that those of number and extension 
are to such a degree innate. 1 ] 

Th. You are right, and indeed I rather believe that the idea 
of extension is posterior to that of whole and part. 

§ 7. Ph. [What say you of the truth that God should be 
worshipped ; is it innate ?] 

Th. I believe that the duty of worshipping God declares that 
on occasion you ought to show that you honor him beyond 
every other object, and that this is a necessary consequence of 
the idea of him and of his existence ; which signifies with me 
that this truth is innate. 

§ 8. Ph. But the atheists seem to prove by their example 
that the idea of God is not innate. And without speaking 
of those whom the ancients have mentioned, have not entire 
nations been discovered, who have no idea of God nor of the 
terms which denote God and the soul, as at the bay of Soldania, 
in Brazil, in the Caribbee Islands, in Paraguay ? 

Th. [The late Mr. Fabricius, 2 a celebrated theologian of 
Heidelberg, has made an apology for the human race in order 

be approximated. On the whole subject, cf. L. Stein, Leibniz u. Spinoza, chap. 6, 
pp. 111-219, Berlin : G. Reimer, 1890, who traces the history of the rise of the 
monad-doctrine from 1680 till all the elements of the complete conception were 
present in 1697 ; E. Dillmann, E. neue Darstg. d. Leibniz. Monadenlehre auf 
Grund d. Quellen, Leipzig: O. R. Reisland, 1891, whose monograph is an elab- 
orate discussion of the entire subject with references to or quotations from all 
the sources. — Tr. 

1 The French text is : " puisque vous soutiendre's apparemment, qu'il y a des 
idees innees respectives, et que celles des nombres et de l'e'tendue sont innees 
aussi." — Tr. 

2 John Lewis Fabricius, 1632-1697. Professor, first of Greek, then of Philos- 
ophy and Theology, at Heidelberg. In 1664 he received the title of " Conseiller 
ecclesiastique de l'electeur palatin." Some years after, when Heidelberg was 
burning, he saved the archives of the church and the university, carrying 
them first to Eberbach, then to Frankfort, where he died. The title of the 
work referred to in the text (vid. ante, p. 21 also, where the name is given 
Fabritius, in accord with his own signature in the letter of Feb. 16, 1673, to 
Spinoza, offering him the professorship of Philosophy at Heidelberg) is: Apol- 
ogia generis humani contra calumniam atheismi. It appeared in 1662. His 
collected works, with a life, were published by J. H. Heidegger, Zurich, 1698, 
in 4to. — Tr. 



ch. in] ON HUMAN UNDERSTANDING 103 

to clear it of the imputation of atheism. He was an author of 
great accuracy, and decidedly above much prejudice; I do not, 
however, pretend to enter into this discussion of facts. I grant 
that entire peoples have never thought of the supreme sub- 
stance, nor of the nature of the soul. And I remember, that 
when you wished at my request, countenanced by the illus- 
trious Mr. Witsen, to obtain for me in Holland a translation of 
the Lord's Prayer into the language of Barantola, you were 
stopped at this point : hallowed be thy name, because you 
could not make the Barantoli understand what hallowed 
meant. I remember also that in the creed made for the Hot- 
tentots you were obliged to express Holy Spirit by words of 
the country which signify a pleasant and agreeable wind. 1 
This was not unreasonable, for our Greek and Latin words 
Trvev/xa. anima, spiritus, mean ordinarily only the air or wind 
we breathe, as one of the most subtile things which we know 
through the senses ; and we begin through the senses to lead 
men little by little to what is beyond the senses. All this diffi- 
culty, however, which you find in attaining abstract knowledge 
effects nothing against innate knowledge. There are peoples 
who have no word corresponding to the word being ; does any 
one doubt their knowledge of what being is, although they 
seldom think of it in the abstract ? Besides I find what I 
have read in our excellent author on the idea of God (Essay on 
Understanding, Book I., chap. 3, 2 § 9) so beautiful and so to 
my liking that I cannot refrain from quoting it. 3 Here it is : 
" Men can scarcely avoid having some kind of idea of things 
of which those with whom they converse often have occasion 
to speak under certain names, and if the thing is one which 
carries with it the idea of excellence, of grandeur, or of some 
extraordinary quality which interests in some point and which 
impresses itself upon the mind under the idea of an absolute 
and irresistible power which none can help fearing " (I add : 
and under the idea of a superlatively great goodness which 
none can help loving), "such an idea ought, according to all 

i Cf. Book III., chap. 1, § 5, Th. (2). — Tr. 

2 Chap. 4, in Locke's treatise, Bohn's ed. — Tr. 

3 The French translation of Locke's original, is, in my judgment, clearer in 
form of statement and style than Locke himself. Hence I have retranslated the 
French into English. If any reader prefers Locke's original, he can easily find 
it in the Philos. Works, Bohn's ed., Vol. 1, p. 188. — Tr. 



104 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

appearances, to make the strongest impression and to spread 
farther than any other, especially if it is an idea which accords 
with the simplest insight of reason, and which flows naturally 
from every part of knowledge. Now such is the idea of God, 
for the brilliant marks of extraordinary wisdom and power 
appear so plainly in all the works of the creation, that every 
rational creature who will reflect thereupon cannot fail to dis- 
cover the author of all these marvels ; and the impression that 
the discovery of such a Being must naturally make upon the 
souls of all those who have once heard him spoken of is so great, 
and carries with it thoughts of so great weight and so adapted 
to spread themselves in the world, that it appears to me wholly 
strange that an entire nation of men can be found upon the 
earth so stupid as to have no idea of God. This, I say, seems 
to me as surprising as to think of men who should have no 
idea of numbers or of fire." 

I would I might always be allowed to copy word for word a 
number of other excellent passages of our author, which we are 
obliged to pass by. I will only say here, that this author, in 
speaking of the simplest lights of reason, which agree with the 
idea of God, and of that which naturally proceeds from it, ap- 
pears to differ but little from my view of innate truths ; and, 
concerning this, that it appears to him as strange that there 
may be men without any idea of God, as it would be surprising 
to find men who had no idea of numbers or of fire, I will remark 
that the inhabitants of the Marian Islands, to which has been 
given the name of the Queen of Spain, who has protected mis- 
sions there, had no knowledge of fire when they were dis- 
covered, as appears from the narrative which Eev. Father 
Gobien, 1 a French Jesuit, charged with the care of distant 
missions, has given to the public and sent to me.] 

§ 16. Ph. If you are right in concluding that the idea of 
God is innate, from the fact that all enlightened races have 
had this idea, virtue ought also to be innate because enlightened 
races have always had a true idea of it. 

Th. [Not virtue, but the idea of virtue, is innate, and per- 
haps you intend only that.] 

1 Charles le Gobien, 1653-1708. Professor of Philosophy at Tours; secre- 
tary and procurator of Chinese missionaries; wrote and published a number 
of works on these missions in China ; his Histoire des Isles Mariannes, Parisi 
1700, 12mo.— Tr. 



en. in] ON HUMAN UNDERSTANDING 105 

Ph. It is as certain that there is a God, as it is certain that 
the opposite angles made by the intersection of two straight 
lines are equal. And there has never been a rational creature 
who applied himself sincerely to the examination of the truth 
of these two propositions who has failed to give them his con- 
sent. Nevertheless, it is beyond doubt that there are many 
men who, having never turned their thoughts in this direction, 
are ignorant equally of these two truths. 

Th. [I admit it ; but that does not prevent them from being 
innate — that is to say, does not prevent you from being able 
to find them in yourself.] 

§ 18. Ph. It would be more advantageous to have an innate 
idea of substance; but it turns out that we do not have it, 
either innate or acquired, since we have it neither through 
sensation nor reflection. 

Th, [I am of opinion that reflection suffices to discover 
the idea of substance within ourselves, who are substances. 
And this notion is one of the most important. But we shall 
speak of it, perhaps more fully, in the sequel of our con- 
ference.] 

§ 20. 1 Ph. If there are innate ideas in the mind without the 
mind's being actually aware of their presence, they must at 
least be in the memory, whence they must be drawn by means 
of reminiscence — that is to say, be known, when memory re- 
calls them, as so many perceptions which have been in the 
mind before, unless reminiscence can subsist without reminis- 
cence. For this conviction, where it is an inwardly certain 
one, that a given idea has previously been in^our mind, is 
properly what distinguishes reminiscence from every other 
kind of thinking. 

Th. [In order that knowledge, ideas, or truths be in our 
mind, it is not necessary that we have ever actually thought of 
them ; they are only natural habitudes ; i.e. dispositions and 
aptitudes, active and passive, and more than a tabula rasa. 
It is true, however, that the Platonists believed that we have 
already actually thought of that which we recognize in our- 
selves ; and to refute them it is insufficient to say that we do 
not at all remember it, for it is certain that an infinite number 

1 Gerhardt's reading. So also Locke, Philos. Works, Vol. 1, p. 197, Bolin's 
ed. — Tr. 



106 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

of thoughts recur to us which we have forgotten that we 
had. It has happened that a man believed he had composed a 
new verse, which it turned out he read word for word a long 
time previous in some ancient poet. And often we have an 
extraordinary facility of conceiving certain things, because we 
formerly conceived them, without remembering them. It is 
possible that a child, having become blind, forgets ever having 
seen light and colors, as happened at the age of two and a half 
years from small-pox in the case of the celebrated Ulric Schoen- 
berg, a native of Weide, in the Upper Palatinate, who died at 
Konigsberg, in Prussia, in 1649, where he taught philosophy 
and mathematics to the admiration of every one. It may be 
that such a man has remaining effects of former impressions 
without remembering them. I believe that dreams often thus 
revive in us former thoughts. Julius Scaliger, 1 having cele- 
brated in verse the illustrious men of Verona, a certain self- 
styled Brugnolus, a Bavarian by birth, but afterward estab- 
lished at Verona., appeared to him in a dream and complained 
that he had been forgotten. Julius Scaliger, not remembering 
to have heard him spoken of before, did not allow himself to 
make elegiac verses in his honor in consequence of this dream. 
At length, the son, Joseph Scaliger, 2 travelling in Italy, learned 
more particularly that there had been formerly at Verona a 
celebrated grammarian or learned critic of this name, who had 
contributed to the re-establishment of polite literature in Italy. 
This story is found in the poems of Scaliger the father, to- 
gether with the elegy, and in the letters of the son. It is 
related also in the " Scaligerana," 3 which are culled from the 

1 Julius Caesar Scaliger, 1484-1558. His Latin verse appeared in successive 
volumes in 1533, 1534, 1539, 1546, 1574. His tastes were, however, philosophi- 
cal and scientific rather than literary. His scientific works, in the form of 
commentaries, have only a historical interest. The Exotericarum exercitatio- 
num liber, Paris, 1557, 4to, a philosophical treatise on the Be Subtilitate, 1552, 
of Cardan (vicl. ante, p. 67, note 1), is the work which hest makes known 
Scaliger as a philosopher. It was a popular text-book until the final fall of 
Aristotle's physics. — Tr. 

2 Joseph Justus Scaliger, 1540-1609, reputed the greatest scholar of modern 
times. He was the first to set forth and apply sound principles of textual 
criticism and emendation in his editions of some of the classical authors, and 
with him arose a new school of historical criticism. He reconstructed the lost 
Chronicle of Eusebius, a work of considerable importance in the study of 
ancient history. — Tr. 

3 Two collections of anecdotes concerning Joseph Scaliger, numbered accord- 



ch. in] ON HUMAN UNDERSTANDING 107 

conversations of Joseph Scaliger. It is very likely that Julius 
Scaliger had known something of Brugnol which he no longer 
remembered, and that the dream was partly the revival of a 
former idea, although he may not have had that reminiscence, 
properly so called, which makes us know that we have already 
had this same idea ; at least, I see no necessity which obliges 
us to assert that there remains no trace of a perception when 
there is not enough of it to remind us that we have had it.] 

§ 24. Ph. [I must admit that your reply is natural enough 
to the difficulties which we have framed against innate truths. 
Perhaps, also, our authors do not contest them in the sense in 
which you maintain them. Thus I return only to say to you, sir] 
that we have had some reason to fear that the view of innate 
truths serves as a pretext for laziness, for exempting ourselves 
from the trouble of research, and gives opportunity to masters 
and teachers to lay down as a principle of principles that 
principles must not be questioned. 

Th. [I have already said that if it is the aim of your friends 
to advise the search for the proofs of the truths which 
they can receive, without distinguishing whether or not they 
are innate, we are entirely agreed ; and the view of innate 
truths, of the manner in which I take them, should deter no one 
from such search, for, besides being well to seek the reason of 
the instincts, it is one of my great maxims that it is good to 
seek demonstrations of the axioms also, and I remember that 
at Paris, when the late Mr. Roberval, 1 already an old man, was 

ing to their date of composition. The first was written in Latin by Francois 
Vertunien, a friend of Scaliger, who took notes of his conversations with 
Scaliger, especially of all criticisms or anecdotes worthy of preservation, and 
afterwards wrote them out. An advocate, Francois de Sigogne, bought the 
MS. long after the author's death, and published it at Saurner in 1669. The 
second was written in French and Latin by two youths named Vassan, who, 
when students at Leyden, habitually conversed after supper with Scaliger, then 
Professor of Belles Lettres there, and on their return to their rooms wrote out 
all they could remember of his conversation. Their MS. was finally published 
at La Haye, 1666, by Isaac Vossius. The edition of the Scaligerana, accounted 
the best, is that of 1740, 12mo. The story is told at length, and the Elegy of 
the elder Scaliger cited, in the Cologne ed. of the Scaligerana, 1695, pp. 69- 
71. — Tr. 

1 Gilles Personne de Roberval, a French geometer, born 1602, at Roberval, a 
small village of Beauvais, died 1675 at Paris. He was Professor of Mathematics 
in the Royal College of France for many years. One of the conditions of the 
tenure of this chair was that its holder should propose mathematical questions 
for solution, and resign in favor of any one solving them better than himself. 



108 LEIBNITZ'S CRITIQUE OF LOCKE [bk. i 

laughed at because he wished to demonstrate those of Euclid 
after the example of Apollonius l and Proclus, 2 1 illustrated the 
utility of this investigation. As for the principle of those 
who say that it is wholly unnecessary to argue against the one 
who denies principles, it has no authority whatever in regard to 
these principles which can admit neither doubt nor proof. It 
is true that, in order to avoid scandal and disturbance, regula- 
tions may be made regarding public disputations and some 
other lectures, in virtue of which the discussion of certain 
established truths may be prohibited. But this is rather a 
question of police than of philosophy.] 

Roberval kept the chair till his death. He is best known for his original 
method for the construction of tangents. — Tr. 

1 Apollonius of Perga, born probably about 250 B.C., died in the reign of 
Ptolemy Philopater, 222-205 b.c. Next to Archimedes, he was the most noted 
of the Greek geometers. His fame has been transmitted to modern times 
chiefly by his treatise on the Conic Sections, the best edition of which, and the 
only one containing the Greek text that has yet appeared, is : Apollonii 
pergaei conicorum libri octo, etc., ed. Halley : Oxford, 1710, folio. He was the 
first to show that all three of the conic sections can be cut from the same cone 
•by changing the jiosition of the intersecting plane. — Tr. 

2 Proclus Diadochus, 410-485, " the great schoolman of Neo-Platonism," the 
doctrines of which received at his hands the final form in which they have 
come down to us. He came to Athens in his twentieth year, and remained 
there teaching and writing till his death. Among his writings now extant are 
a Treatise on the Sphere, Commentaries on Euclid, and on several of Plato's 
dialogues, and the wholly independent works Stoix^Wk? ©coAc^ikt), or Institutes 
of Theology, and the six books ei? iV rUaTwi-o? ®eo\oyiav, or Platonic Theology. 
His philosophical work is found for the most part in the Commentaries on Plato. 
For his mathematical work, ef. In primum Euclidis Elementorum librum 
Commentarii, ex recognitione G. Friedlein : Lipsife, 1873 ; also George Johnston 
Allman, Greek Geometry from Thales to Euclid, Dublin: University Press, 
1889; and in " Hermathena," a series of papers on literature, science, and phi- 
losophy, by members of Trinity College, Dublin, Nos. 5, 7, 10-13, Dublin: 1878, 
1881, 1884-1887. For his philosophy, cf Zeller, Die Philos. d. Griech., 3d ed., 
1881, Vol. 3, pp. 774 sq., and Outlines, § 101 ; Hegel, Gesch. d. Philos., 2d ed., 
Vol. 3, pp. 61-79; Alfred William Benn, The Greek Philosophers, Vol.2, pp. 
358-360, London: Kegan Paul, Trench, & Co., 1882. The Philosophical and 
Mathematical Commentaries on the First Book of Euclid's Elements, etc., 
were translated by Thomas Taylor, London, 1792, 2 vols, in 1, 4to. — Tr. 



NEW ESSAYS ON HUMAN UNDERSTANDING 

Book II. — Ideas 
CHAPTER I 

WHICH TREATS OF IDEAS IN GENERAL, AND EXAMINES BY THE 
WAY WHETHER THE MIND OF MAN ALWAYS THINKS 

§ 1. Ph. Having examined the question of innate ideas, let 
us consider their nature and their differences. Is it not true 
that the idea is the object of thought ? 

Th. [I admit it, provided you add that it is an immediate 
internal object, and that this object is an expression of the na- 
ture or the qualities of things. If the idea were the form of 
thought, it would spring up and cease with the actual thought 
to which it corresponds ; but being the object it may exist pre- 
vious to and after the thoughts. External sensible objects are 
only mediate because they cannot act immediately upon the 
soul. 1 God alone is the external immediate object. We might 
say that the soul itself is its own immediate internal object ; 
but it is this in so far as it contains ideas, or what corresponds 
to things. For the soul is a little world, 2 in which distinct 
ideas are a representation of God, and in which confused ideas 
are a representation of the universe.] 

§ 2. Ph. We who suppose that at the beginning the soul is a 
tabula rasa, void of all characters and without an idea, ask how 
it comes to receive ideas, and by what means it acquires this 

1 Cf. Book IV., chaps. 9 and 11. The opposition here set up between mediate 
and immediate knowledge corresponds to Kant's a posteriori and a priori 
knowledge. — Tr. 

2 Microcosm. — Tr. 

109 



110 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

prodigious quantity of them ? To that question the reply in a 
word is : From experience. 

Th. [This tabula rasa, of which so much is said, is in my 
£- opinion only a fiction which nature does not admit, and which 
is based only upon the imperfect notions of philosophers, like 
the vacuum, atoms, and rest, absolute or relative, of two 
parts of a whole, or like the primary matter 1 which is con- 
ceived as without form. Uniform things and those which con- 
tain no variety are never anything but abstractions, like time, 
space, and the other entities of pure mathematics. There is no 
body whatever whose parts are at rest, and there is no sub- 
stance whatever that has nothing by which to distinguish it 
from every other. Human souls differ, not only from other 
souls, but also among themselves, although the difference is 
not at all of the kind called specific. And, according to the 
proofs which I believe we have, every substantial thing, be it 
soul or body, has its own characteristic relation to every other; 
and the one must always differ from the other by intrinsic 
connotations. Not to mention the fact that those who speak 
so frequently of this tabula rasa after having taken away the 
ideas cannot say what remains, like the scholastic philoso- 
phers, who leave nothing in their primary matter. 1 You 
may perhaps reply that this tabula rasa of the philosophers 
means that the soul has by nature and originally only bare fac- 
ulties. But faculties without some act, in a word the pure 
powers of the school, are also only fictions, which nature 
knows not, and which are obtained only by the process of ab- 
straction. For where in the world will you ever find a faculty 
which shuts itself up in the power alone without performing 
any act ? There is always a particular disposition to action, 
and to one action rather than to another. And besides the 
disposition there is a tendency to action, of which tendencies 
there is always an infinity in each subject at once ; and these 
tendencies are never without some effect. Experience is nec- 
essary, I admit, in order that the soul be determined to such 
or such thoughts, and in order that it take notice of the ideas 
) which are in us ; but by what means can experience and the 
I senses give ideas ? Has the soul windows, does it resemble 
tablets, is it like wax ? It is plain that all who so regard the 
1 Materia Prima. — Tb. 



ch. i] ON HUMAN UNDERSTANDING 111 

soul, represent it as at bottom corporeal. You oppose to me this 
axiom received by the philosophers, that there is nothing in the 
soul which does not come from the senses. But you must except 
the soul itself and its affections. Nihil est in intellectu, quod 
non fuerit in sensu, excipe : nisi ipse intellectus. Now the soul 
comprises being, substance, unity, identity, cause, perception, 
reason, and many other notions which the senses cannot give. 
This view sufficiently agrees with your author of the Essay, who 
seeks the source of a good part of ideas in the spirit's reflec- 
tion upon its own nature. 

Ph. [I hope, then, that you will agree with this skilful 
author that all ideas come through sensation or through re- 
flection, that is to say, from observations which we make either 
upon objects exterior and sensible or upon the inner workings 
of our soul. 

Th. [In order to avoid a discussion upon what has delayed 
us too long, I declare to you in advance, sir, that when you 
say that ideas come to us from one or the other of these causes, 
I understand the statement to mean their actual perception, 
for I think I have shown that they are in us before they are 
perceived so far as they have any distinct character. 

§ 9. Ph. [In the next place let us inquire when we must 
say that the soul begins to perceive and actually to think of 
ideas. I well know that there is an opinion which states that 
the soul always thinks, and that actual thought is as inseparable 
from the soul as actual extension is from the body. § 10. But 
I cannot conceive that it is any more necessary for the soul 
always to think than for the body always to be in motion, per- 
ception of ideas being to the soul what movement is to the 
body. That appears to me very reasonable at least, and I 
would gladly know your view, sir, thereupon. 

Th. You have stated it, sir. Action is no more connected 
with the soul than with the body, a state without thought in 
the soul and an absolute repose in the body appearing to me 
equally contrary to nature, and without example in the world. 
A substance once in action, will be so always, for all the im- 
pressions remain and are merely mingled with other new ones. 
Striking a body, we arouse therein or determine rather an 
infinite number of vortices as in a liquid, for at bottom every 
solid has a degree of liquidity and every liquid a degree of 



112 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

solidity, and there are no means of ever stopping entirely these 
internal vortices. Now we may believe that if the body is 
never at rest, the soul, which corresponds to it, will never be 
without perception either.] 

Ph. But it is, perhaps, a privilege of the author and conserver 
of all things, that being infinite in his perfections, he never slum- 
bers nor sleeps. This is not granted to any finite being, or at 
least not to such a being as is the soul of man. 

Th'. [It is certain that we slumber and sleep, and that God 
is exempt from both. But it does not follow that we have no 
perception while asleep. Bather just the contrary is found to 
be the case, if we consider it carefully.] 

Ph. There is something in us which has the power to think ; 
[but it does not thereby follow that it is always in action.] 

Th. [Real powers are never simple possibilities. They have 
always tendency and action. 

Ph. But this proposition — the soul always thinks — is not 
self-evident. 

Th. I do not say it is. A little attention and reasoning is 
necessary to discover it ; the common people perceive it as little 
as they do the pressure of the air or the roundness of the earth.] 

Ph. I doubt if I thought last night ; this is a question of fact, 
it must be decided by sensible experiences. 

Th. [It is decided as it is proved, that there are imperceptible 
bodies and invisible movements, although certain persons treat 
them as absurd. There are also numberless perceptions little 
noticed which are not sufficiently distinguished to be perceived 
or remembered, but they become known through certain conse- 
quences.] 

Ph. There was a certain author who raised the objection that 
we maintain that the soul ceases to exist, because we are not 
sensible of its existence during our sleep. But this objection 
can arise only from a strange prepossession, for we do not say 
that there is no soul in man because we are not sensible of its 
existence during our sleep, but only that man cannot think 
without being aware of it. 

Th. [I have not read the book which contains this objection, 
but it would not have been wrong merely to object to you that 
it does not follow because the thought is not perceived, that it 
ceases for that reason ; for otherwise it could be said for the 



ch. i] ON HUMAN UNDERSTANDING 113 

same reason that there is no soul during the time in which it 
is not perceived. And to refute this objection it is necessary 
to point out in particular the thought that it is essential to it 
that it be perceived.] 

§ 11. Ph. It is not easy to conceive that a thing can think 
and not be conscious that it thinks. 

Th. There is, doubtless, the knot of the affair and the diffi- 
culty which has embarrassed able men. But here are the means 
of extricating ourselves therefrom. We must consider that we 
think of many things at a time, but we attend only to the 
thoughts which are most distinct, and the process cannot go 
on otherwise, for if we should attend to all, we would have to 
think attentively of an infinite number of things at the same 
time, all of which we feel and which make an impression upon 
our senses. I say even more : there remains something of all 
our past thoughts, and none can ever be wholly effaced. Now 
when we sleep without dreaming and when we are stunned by 
some blow, fall, symptom, or other accident, an infinite number 
of minute confused sensations take form within us, and death 
itself can produce no other effect upon the souls of animals, 
who ought, doubtless, sooner or later, to acquire distinct per- 
ceptions, for all goes on in an orderly way in nature. I admit, 
however, that in this state of confusion, the soul would be with- 
out pleasure and without pain, for these are noticeable percep- 
tions. 

§ 12. Ph. Is it not true that those with whom we have at 
present to do, [i.e. the Cartesians, who believe that the soul 
always thinks,] grant life to all animals, differing from man, 
without giving them a soul which knows and thinks ; and that 
these same (Cartesians) find no difficulty in saying that the soul 
can think independently of a body ? 

Th. [For myself, I am of another opinion, for although I 
agree with the Cartesians in their affirmation that the soul 
thinks always, I am not agreed with them in the two other 
points. I believe that the beasts have imperishable souls and 
that human and all other souls are never without some body. 
I hold also that God alone, as being an actus purus, is wholly 
exempt therefrom.] 

Ph. If you had been of the opinion of the Cartesians, I should 
have inferred therefrom, that the bodies of Castor or Pollux 



1U LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

could be sometimes with, sometimes without a soul, though 
being always alive, and the soul having the ability also to be 
sometimes in one body and sometimes elsewhere, we might 
suppose that Castor and Pollux had only a single soul, which 
was active alternately in the body of these two men sleeping 
and awake by turns ; thus it would be two persons as distinct 
as Castor and Pollux could be. 

Th. I, in my turn, will make you another supposition, 
which appears more real. Is it not true that we must always 
admit that after some interval or some great change, one may 
fall into a state of general forgetfulness ? Sleidan 1 (they say), 
before his death, forgot all he knew ; and there are many 
other examples of this sad event. Suppose that such a man 
became young again and learned all anew, will he be another 
man on that account ? It is not then memory which, properly 
speaking, makes the same man. Nevertheless, the fiction of a 
soul which animates different bodies in turn, without concern- 
ing itself in one of these bodies with that which happens to it 
in the other, is one of those fictions contrary to the nature of 
things which arise from the imperfect notions of philosophers, 
as space without body and body without motion, and which dis- 
appear when one penetrates a little deeper ; for you must know 

1 John Sleidan, original name Philipsohn, c. 1506-1556, the annalist of the 
Reformation. He was secretary for five years from 1536 to Cardinal du Bellay, 
minister of Francis I. of France. He was wont to copy all documents bearing 
upon the Reformation to which he had access, and upon the suggestion of 
Bucer to Philip of Hesse, after some delay was appointed, with the consent 
of the heads of the Schmalkaldic League, historian of the Reformation, with a 
salary and access to all necessary documents. He finished the first volume of 
his great work in 1545. His work was then interrupted by a diplomatic mis- 
sion in a French embassy to Henry VIII. of England. While there he improved 
every opportunity to collect materials for his history. In 1551 he was a mem- 
ber of the Council of Trent for Strassburg. On his return he was made Pro- 
fessor of Law at Strassburg, a position which enabled him to devote his whole- 
attention to his great work. It was finished for the press in 1554, and published 
at Strassburg in 1555. It is entitled : Commentariorum de statu religionis et 
reipublicss Carolo Quinto, Csesare, libri XXVI. The ed. of 1555 contained 
only 25 books ; that of 1559 the 26th and an apology of Sleidan, written by 
himself. The best edition is that of Francfort, 1785-86, 3 vols., 8vo. The work 
is "the most valuable contemporary history of the times of the reformation, 
and contains the largest collection of important documents." It is especially 
noteworthy for its accuracy, impartiality, and purity of style. There are two 
English translations, by John Daws, 1560, and G. Bohum, 1689. There are 
also translations in other languages. Cf. H. Baumgarten, Ueber Sleidanus 
Leben und Briefwechsel, 1878 ; Sleidans Briefwechsel, 1S81. — Te. 



ch. i] ON HUMAN UNDERSTANDING 115 

that each soul preserves all its preceding impressions, and 
cannot divide itself equally in the manner just mentioned ; the 
future in each substance is perfectly united to the past ; this 
is what constitutes the identity of the individual. Memory, 
furthermore, is not necessary, nor even always possible, because 
of the multitude of present and past impressions which co-op- 
erate in our present thoughts, for I do not believe that there 
are in man thoughts of which there is not some effect at least 
confused or some remnant mixed with subsequent thoughts. We 
can forget many things, but we could also remember them long 
after if we would recall them as we ought. 

§ 13. Ph. Those who chance to sleep without dreaming can 
never be convinced that their thoughts are active. 

Th. [One is feebly conscious in sleep, even when it is dream- 
less. The process of waking up itself shows this, and the easier 
you are awakened the more you are conscious of what goes on 
without, although this consciousness is not always strong enough 
to cause you to awake.] 

§ 14. Ph. It appears very difficult to conceive that the soul 
is thinking at this moment in a sleeping man and the next in 
one awake, without remembering its thoughts. 

Th. [Not only is that easy to conceive, but also something 
like it is observed every day that we are awake ; for we always 
have objects which strike our eyes and ears, and, as a result, 
the soul is touched also, without our taking notice of it, because 
our attention is bent upon other objects, until this object becomes 
strong enough to draw it to itself, by redoubling its action or by 
some other means ; it is like a particular sleep with reference 
to that object, and this sleep becomes general when our atten- 
tion ceases to regard all objects together. Division of 'attention, 
in order to weaken it, is also a means of putting yourself to sleep.] 

Ph. I learned from a man, who in his youth had applied him- 
self to study and had a tolerably felicitous memory, that he 
never had a dream until he had had the fever, from which he 
had just recovered at the time he spoke with me, at the age of 
twenty-five or twenty-six years. 

Th. [I have also been told of a student, more advanced in 
years, who never had a dream. But it is not upon dreams alone 
that you must base the perpetuity of the soul's perception, since 
I have shown how, even while asleep, it has some perception of 
what goes on without.] 



110 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

§ 15. Ph. To think frequently and not to preserve a single 
moment the memory of your thought, is to think in a useless 
manner. 

Th. [All impressions have their effect, but all the effects are 
not always perceptible ; when I turn to one side rather than to 
the other, it is very often through a series of minute impressions 
of which I am not conscious, and which render one movement 
a little more uncomfortable than the other. All our unpre- 
meditated actions are the results of a concurrence of minute 
perceptions, and even our customs and passions, which influ- 
ence so much our deliberations, come therefrom; for these 
habits grow little by little, and, consequently, without the 
minute perceptions, we should not arrive at these noticeable dis- 
positions. I have already remarked that he who would deny 
these effects in the sphere of morals, would imitate the poorly 
taught class who deny insensible corpuscles in physics ; and 
yet I see that among those who speak of liberty are some who, 
taking no notice of these unperceived impressions, capable of 
inclining the balance, imagine an entire indifference in moral 
actions, like that of the ass of Buridan 1 equally divided between 
two meadows. Concerning this we shall speak more fully 
later. I admit, however, that these impressions incline with- 
out necessitating. 

Ph. Perhaps we might say that in the case of a man awake 
who thinks, his body counts for something and that memory 
is preserved by means of marks in the brain, but when he is 
asleep the soul thinks apart by itself. 

1 John Buridan, a celebrated Nominalist of the 14th century, the date of 
whose birth and death is unknown. He studied at Paris under William of 
Occam (died 1347) and was for many years Professor of Philosophy in the 
University of Paris, and in 1327 its rector. In philosophy his only authority 
was reason. In the third book, first question, of his Qusestiones in decern libros 
ethicorum Aristotelis, 1489, he discussed in an "independent and interesting 
manner " the question of the freedom of the will, reaching conclusions similar 
to those of Locke. In his view the liberty possessed by the soul consists in 
" a certain power of suspending the deliberative process, and determining the 
direction of the intellect ; otherwise the will is entirely dependent on the view 
of the mind, the last result of examination." The story of the ass as an illus- 
tration of the indeterminism of the will " is not," as Sir William Hamilton 
says (Reid, 8th ed., Vol. 1, p. 238, note) he has ascertained, "to be found in 
his writings." On Buridan, cf. Ueberweg, Hist, of Philos., English transla- 
tion, Vol. 1, pp. 465-466 ; Prantl, Gesch. <L Loghk, Vol. 4, 14-38 ; Stockl, Gesch. 
d. Philos. d. Mittelalters, Vol. 2, 1023-1028. — Tb. 



ch. i] ON HUMAN UNDERSTANDING 117 

Th. I am very far from saying that, since I believe there 
is always an exact correspondence between the body and 
the soul, and since I employ the impressions of the body 
of which we are not conscious, whether awake or asleep, in 
order to prove that the soul has in itself similar ones. I 
maintain even that something goes on in the soul which cor- 
responds to the circulation of the blood and to all the internal 
movements of the viscera, of which we are never conscious 
however, just as those who live near a water-mill do not per- 
ceive the noise it makes. In fact, if there were impressions 
in the body during sleep or waking hours, by which the soul 
was not touched or in any wise affected, limits would be given 
to the union of the soul and of the body, as if corporeal 
impressions required a certain form and size in order for the 
soul to perceive them ; which is not at all tenable if the soul 
is incorporeal, for there is no relation between an incorporeal 
substance and this or that modification of matter. In a 
word, it is a great source of error to believe that there is no 
perception in the soul besides those of which it is con- 
scious. 

§ 16. Ph. The greater part of the dreams which we remem- 
ber are extravagant and incoherent. We should then say that 
the soul owes the power of rational thought to the body, or 
that it retains none of its rational soliloquies. 

Th. [The body responds to all the soul's thoughts, rational 
or not, and dreams have also their marks in the brain as well 
as the thoughts of those who are awake. 

§ 17. Ph. Since you are so sure that the soul is always 
actually thinking, I wish you would tell me what the ideas 
are which are in the child's soul before it is united to the body, 
or just at the time of its union, before it has received any idea 
by means of sensation. 

Th. It is easy to satisfy you by our principles. The soul's 
perceptions correspond always naturally to the constitution of 
the body, and when there are a multitude of movements con- 
fused and little distinguished in the brain, as happens in the 
case of those who have little experience, the soul's thoughts 
(following the order of the things) cannot be more distinct. Yet 
the soul is never deprived of the help of sensation, because it 
always expresses its body, and this body is always impressed 



118 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

by its surroundings 1 in an infinite number of ways, but which 
often give only a confused impression. 

§ 18. Ph. But here is still another question which the 
author of this Essay asks. I very much wish (says he) that 
those who maintain so confidently that the soul of man or 
(what is the same thing) man thinks always, would tell me 
how they know it ? 

Th. [I do not know but that more confidence is necessary to 
deny that anything goes on in the soul of which we are not 
conscious ; for that which is perceivable must be composed of 
parts which are not so, nothing can spring into being at once, 
thought no more than motion. In short, it is as if some one 
asked to-day how we know the insensible corpuscles. 

§ 19. Ph. I do not remember that those who tell us that 
the soul always thinks ever say that man always thinks. 

Th. [I think that is because they understand their state- 
ment of the separated soul, and yet they voluntarily admit that 
man always thinks during the union. For myself, who have 
reasons for holding that the soul is never separated from the 
entire body, I believe that we can state absolutely that man 
always does and will think.] 

Ph. To say that the body is extended without having parts, 
and that a thing thinks without being conscious that it thinks, 
are two assertions which appear equally unintelligible. 

Th. [Pardon me, sir; I am obliged to tell you that when 
you advance the statement that there is nothing in the soul of 
which it is not conscious, you beg the question which has al- 
ready prevailed in all our former discussion, or you have been 
desirous to use it to destroy innate ideas and truths. If we 
agree to this principle, in addition to the fact that we believe 
it contrary to experience and reason, we should surrender with- 
out reason to our feeling, which, I believe, I have rendered 
sufficiently intelligible. But besides the fact that our oppo- 
nents, skilful as they are, have brought no proof of that which 
they urge so often and so positively, it is easy to show them 
the contrary ; i.e. that it is impossible for us always to think 

1 Gerhardt reads : " frappe par les ambiaos d'une infinite de manieres, mais 
qui souvent ne donnent qu'une impression confuse." Erdmann and Jacques 
read: "frappe par les autres, qui l'environnent, d'une infinite de manieres, 
mais qui souvent ne font qu'une impression confuse." — Tr. 



ch. i] ON HUMAN UNDERSTANDING 119 

expressly upon all our thoughts ; otherwise, the spirit would 
reflect upon each reflection to infinity without ever being able 
to pass to a new thought. For example, in my consciousness 
of some present feeling, I should always think that I think, 
and still think that I think of my thought, and thus to infinity. 
But it is very necessary that I cease reflecting upon all these 
reflections, and that there be at length some thought which is 
allowed to pass without thinking of it ; otherwise, Ave should 
dwell always upon the same thing.] 

Ph. But would there not be as good ground for maintaining 
that a man is always hungry, by saying that he can be hungry 
without feeling it ? 

Th. There is just the difference ; hunger has particular rea- 
sons which do not always exist. Nevertheless, it is true also 
that even when you are hungry you do not think of it every 
moment ; but when you do think of it you feel it, for it is a 
very marked disposition; there is always irritation in the 
stomach, but it is necessary for it to become very strong to 
cause hunger. The same distinction ought always to be made 
between thoughts in general and remarkable thoughts. Thus, 
what appears to put a ridiculous construction upon our opinion, 
serves to confirm it.] 

§ 23. Ph. One can now ask, when man begins to have ideas 
in his thought ? And it seems to me that the reply must be, 
when he has some sensation. 

Th. [I am of the same opinion; but it is by a principle a 
little peculiar, for I believe that we are never without thoughts, 
and also never without sensation. I distinguish only between 
ideas x and thoughts ; for we always have all pure or distinct 
ideas independently of the senses ; but thoughts always corre- 
spond to some sensation.] 

§ 25. But the mind is passive only in the perception of 
simple ideas, which are the rudiments or materials of knowl- 
edge, while it is active when it forms complex ideas. 

Th. [How can it be that the mind is passive merely with 
regard to the perception of all simple ideas, since, accord- 
ing to your own admission, there are simple ideas whose per- 

1 Gerhard t reads: "Je distingue seulement entre les idees et les pensees " ; 
Erdmarm and Jacques read: "Je distingue seulement entre sensations et 
' — Tk. 



120 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

ception comes from reflection, and since the mind 1 gives itself 
thoughts from reflection, for it is itself which reflects ? 
Whether it can refuse them is another question, and doubtless 
it cannot (refuse them) without some reason, which turns it 
aside from them, when there is some occasion for it.] 

Ph. [It seems that hitherto we have discussed ex professo. 
Now that we are going to come to the detail of ideas, I hope 
that we shall be more agreed, and that we shall differ only in 
some particulars.] 

Th. [I shall be delighted to see able men adopting the 
views which I hold to be true, for they are adapted to improve 
them and to show them in a good light.] 



CHAPTER II 

SIMPLE IDEAS 

§ 1. Ph. I hope then that you will admit that there are 
simple and complex ideas ; thus heat and softness in wax, and 
cold in ice, furnish simple ideas, for the soul has a uniform 
conception of them, which is not distinguishable into different 
ideas. 

Th. [I believe that we can affirm that these sense-ideas are 
simple in appearance, because, being confused, they do not give 
the mind the means of distinguishing their contents. In like 
manner distant things appear round, because their angles can- 
not be discerned, although some confused impression of them 
is received. It is manifest, for example, that green arises 
from a mixture of blue and yellow ; thus it is possible to 
believe that the idea of green is also composed of these tAvo 
ideas. And yet the idea of green appears to us as simple as 
that of blue or that of warmth. So we are to believe that the 
ideas of blue and warmth are not as simple as they appear. I 
readily consent, however, to treat these ideas as simple ideas, 
because at least our apperception does not divide them, but it 

1 Gerhardt reads ■: "et quel'esprit se dorme " ; Erdmann and Jacques read: 
" et qu'au moms l'esprit se dorme," and since the mind at least gives itself. 
— Tr. 



ch. in] ON HUMAN TJNDEKSTANDING 121 

is necessary to proceed to their analysis by means of other 
experiences and by reason, in proportion as they can be ren- 
dered more intelligible. 1 And it is also seen thereby that 
there are perceptions of which we are not conscious. For the 
perceptions of ideas simple in appearance are composed of per- 
ceptions of the parts of which these ideas are composed, with- 
out the mind's being conscious of them, for these confused ideas 
appear simple to it.] 

CHAPTEE III 

OF IDEAS WHICH COME TO US BY ONE SENSE ONLY 

Ph. ~Now we can arrange simple ideas according to the 
means by which we perceive them, for that is done, 1, by 
means of one sense only ; 2, by means of more than one sense ; 
3, by reflection , or 4, by all the ways 2 of sensation as well as 
by reflection. Thus of those which enter by a single sense 
which is particularly adapted to receive them, light and colors 
enter only by the eyes ; all kinds of noises, sounds, and tones 
enter by the ears ; the different tastes by the palate ; and odors 
by the nose. These organs or nerves carry them to the brain, 
and if any one of these organs chance to be disordered, these 
sensations cannot be admitted by any artificial gate. The 
most considerable qualities belonging to the touch are cold, 
heat, and solidity. The others consist either in the configura- 
tion of the sensible parts, as smooth and rough, or in their 
union, as compact, hard, soft, brittle. 3 

Th. [I quite agree, sir, with what you say, although I may 
remark that, according to the experiment of the late M. 
M ariotte 4 upon the defect of vision with regard to the optic 

1 Erdmann's and Jacques's texts of chap. 2 end here ; Gerhardt's text adds 
the following: " Et Ton voit encor par la qu'il y a des perceptions dont on ne 
s'appercoit point. Car les perceptions des idees simples en apparence sont 
composees des perceptions des parties dont ces idees sont coniposees, sans que 
l'esprit s'eu appercoive, car ces idees confuses luy paroissent simples." — Tr. 

2 Locke's expression. Pliilos. Works, Vol. 1, p. 227, Bohn's ed. — Tr. 

3 Locke uses these forms, instead of the more common abstract forms end- 
ing in -ness. Hence I have used them in the translation. — Tr. 

4 Edme Mariotte, a celebrated French physicist, born about 1620, died 1684. 
He was in some sense the initiator of experimental physics in France. The 
experiment here referred to, and the resulting discovery of the blind spot at 



122 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

nerve, it seems to me that the membranes receive the sensa- 
tion rather than the nerves, and there is an irregular en- 
trance for the hearing and the taste, since the teeth and the 
vertex assist in causing any sound to be heard, and that tastes 
make themselves known to some extent through the nose, by 
reason of the connection of these organs. But all that makes 
no change in the foundation of things as regards the explica- 
tion of ideas. As for the qualities belonging to touch, you 
can say that smoothness or roughness, hardness or softness, 
are only modifications of resistance or solidity.] 



CHAPTEE IV 

OF SOLIDITY 

§ 1. Ph. You will doubtless agree that the idea of solidity 
is caused by the resistance we find in a body to the en- 
trance of another body into the place it occupies until it has 
left it. That which thus hinders the approach of two bodies 
when they are moved one toward another I call solidity. If 
any one finds it more to the purpose to call it impenetrability, I 
give my consent. But I believe that the term solidity bears 
a more positive character. This idea seems most intimately 
connected with and essential to body, and can be found only 
in matter. 

Tli. It is true that we find resistance in touch, when another 
body reluctantly gives place to our own, and it is also true 
that bodies dislike to occupy the same place. Many, how- 
ever, doubt whether this repugnance is invincible, and it is well 
also to consider that the resistance which is found in matter is 
derived in more than one way and by means of reasons quite 
different. A body resists another either when it must leave 
the place which it has already occupied, or when it fails to 
enter the place into which it was ready to enter, because the 
other tries to enter also, in which case it may happen that, the 
one not yielding to the other, they stop or mutually repel each 

the entrance of the optic nerve, was made in 1668. An account of it is given 
in a short paper in the second volume of his collected works. CEuvres de 
Mariotte, 2 vols., Leyden: 1717, 4to. — Tr. 



ch. iv] ON HUMAN UNDERSTANDING 123 

other. The resistance is seen in the change of that (body) to 
which resistance is offered, whether it loses its force, changes 
its direction, or both happen at once. Now you can say in 
general that this resistance arises from the repugnance which 
two bodies have to occupy the same place, which may be 
called impenetrability. Thus when one body makes an effort 
to enter, it at the same time forces the other to attempt to 
leave or to prevent its entrance. But that kind of incompati- 
bility which makes one or the other, or both together, yield, 
being once assumed, there are several reasons besides the one 
named which make one body resist another which endeavors 
to compel its departure. They are either in it or in the neigh- 
boring bodies. There are two which are in itself ; one is pas- 
sive and constant, the other active and variable. The first is 
what I call inertia, 1 after Kepler 2 and Descartes, which impels 
matter to resist motion, and which it is necessary to destroy 
by force in order to move a body, supposing that there were 
neither gravity nor adhesion. Thus a body which undertakes 
to drive forward another, experiences for that reason this re- 
sistance. The other cause, which is active and variable, con- 
sists in the impetuosity of the body itself, which does not 
yield without resistance at the moment its own impetuosity 
carries it into a place. The same reasons reappear in the 
neighboring bodies when the body which resists is unable to 
yield without causing the others to yield also. But then a 
new consideration comes in — viz. : compactness (fermete) or 
the adhesion of one body to another. This adhesion 3 makes 
it impossible to move one body without at the same time mov- 
ing the other to which it adheres, and this causes a kind of 
traction in reference to this other. This adhesion so acts that, 
even should we put aside inertia and manifest impetuosity, 
there would be resistance ; for if space is conceived as filled 
with matter perfectly fluid, and if a single hard body were 
placed within it, this hard body (supposing there were in the 
fluid neither inertia nor impetuosity) will be moved therein 
without finding any resistance ; but if space were full of little 

1 Gerhardt reads " incertie " ; evidently an error. — Tr. 

2 John Kepler, 1571-1630, one of the creators of modern astronomy. His 
complete works were edited by Dr. Ch. Frisch, Joannis Kepleri opera omnia, 
8 vols., Frankfort: 1858-1871. -Tr. 

3 Erdmann and Jacques add " souvent," often. — Tr. 



124 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

cubes, the resistance which the hard body would find, should 
it be moved among the cubes, would come from the fact that 
the little hard cubes, on account of their hardness or because 
of the adhesion of their parts one to another, would with diffi- 
culty be separated as much as would be necessary to make a 
circle of movement, and to fill up the place of the body moved 
at the moment it departs. But if two bodies should enter at 
the same time by the two ends into a tube open on both sides, 
and should fill it to its capacity, the matter in this tube, how- 
ever fluid it be, would resist by its impenetrability alone. 
Thus, in the resistance of which we are here treating, we have 
to consider the impenetrability of bodies, inertia, impetuosity, 
and adhesion. It is true that, in my opinion, this adhesion of 
bodies arises from a more subtile motion of one body toward 
another ; but, as this is a point which may be disputed, it must 
not be assumed at first. And for the same reason we must 
only assume at first an original, essential solidity, which makes 
the place always equal to the body, that is to say that the in- 
compatibility, or, to speak more accurately, the non-consistence 1 
of bodies in the same place is a perfect impenetrability which 
receives neither more nor less, since many maintain that sensi- 
ble solidity can arise from a repugnance on the part of bodies 
to be found in the same place, but which will not prove to be 
an invincible repugnance. For all the ordinary Peripatetics 
and many others believe that the same matter can fill more or 
less space, which phenomenon they call rarefaction or conden- 
sation, not in appearance only (as when water is squeezed from 
a sponge), but rigorously, like the scholastic conception of the 
air. I am not of this opinion ; but I do not think that I ought 
at first to assume the opposite opinion, the senses, apart from 
the reasoning faculty, not sufficing to establish this perfect im- 
penetrability, which I hold to be true in the order of nature, 
but which is not learned by sensation alone. And some one 
may claim that the resistance of bodies to compression arises 
from an effort of the parts to spread themselves when they 
have not their entire liberty. For the rest the eyes aid 
greatly in proving these qualities, coming to the assistance of 

1 Leibnitz's word is "l'inconsistence," and, as it is apparently technical, I 
have decided to transfer it, merely changing the form of the negative in- to 
non- to avoid ambiguity. — Tr. 



en. iv] ON HUMAN UNDERSTANDING 125 

touch. And at bottom solidity, so long as it presents a dis- 
tinct idea, is conceived by pure reason, although the senses 
furnish the reasoning faculty with the proof that it is in 
nature. 

§ 4. Ph. We are at least agreed that the solidity of a body 
carries with it the filling of the space it occupies in such a 
way as absolutely to exclude every other body [if a space can 
be found in which there was none before], while hardness [or 
the consistence rather which some call compactness (fer- 
mete)\ is a strong union of certain parts of matter, which 
make up masses of a sensible size, so that the whole mass does 
not easily change its form. 

Th. [This consistence, as I have already remarked, is pre- 
cisely what makes it difficult to move one part of a body with- 
out the other, so that when one part is pushed, the other, 
which is not pushed, and which does not fall within the line 
of tendency, is nevertheless induced to go from that side by a 
kind of traction; and, further, if this last part finds any obsta- 
cle which holds or pushes it back, it draws it along, or holds 
back, also, the first part ; and this action is always reciprocal. 
The same thing sometimes happens in the case of two bodies 
which do not touch and which do not form a continuous body 
whose parts are contiguous ; and yet, the one pushed compels 
the other to go without pushing it, so far as the senses can 
give us knowledge. Of this the animant, 1 electrical attraction, 

1 See Krauth-Fleming, Vocab. Philos. Sciences, pp. 28, 29, and 571, edition 
of 1877, New York: Sheldon & Co., 1883. The animant is that which pos- 
sesses and imparts life. Together with its cognates animality, animalish, 
animalist, used frequently by Cudworth. See Intell. Syst., 514, " Ut sit 
Animans, that it be Animant, or endued with Life, Sense, and Understand- 
ing." Ibid., 198. "But no Atheist ever acknowledged conscious animality 
to he a first principle in the universe ; nor that the whole was governed by 
any animalist, sentient, and understanding nature, presiding over it as the 
head of it." The term being technical, and, with its cognates, more or less 
current in the seventeenth century, it seemed best to retain it, defining and 
illustrating as above. Its meaning is, I think, sufficiently evident. It is to 
be noticed, however, that Erdmann, in his Errores Typographies, prefixed 
to his edition, reads aimant instead of animant. Jacques's text also has 
aimant. The translation would then be: The loadstone or magnet; and 
Schaarschmidt, following this reading, renders it " der Magnet," in his German 
translation of the Nouveavx Essais, in J. H. v. Kirchmann's Philos. Bibliothek, 
Berlin, 1873. As I translate on the basis of Gerhardt's text I retain his read- 
ing and its translation, with the note explaining the term, although at the 
present writing the reading of Erdmann and Jacques seems more congruous 
with the context, and so more likely to be the true one. — Tr. 



126 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

and that which was formerly ascribed to the fear of a vacuum, 
furnish examples.] 

Ph. It seems that, in general, hard and soft are names which 
we give to things solely as related to the particular constitu- 
tion of our bodies. 

Th. [But then many philosophers would not ascribe hard- 
ness to their atoms. The notion of hardness does not depend 
upon the senses, and its possibility can be conceived by the 
reason, although we are further convinced by the senses that 
it is actually found in nature. I should, however, prefer the 
word compactness — fermete (if I were allowed to use the word 
in this sense) — to that of hardness, for there is some compact- 
ness even in soft bodies. I seek even a more suitable and 
general term, like consistence or cohesion. Thus I would 
oppose hard to soft, solid to fluid, for wax is soft, but, unless 
melted by heat, it is not fluid and preserves its bounds ; and 
in fluids even there is ordinarily cohesion, as is shown in drops 
of water and of mercury. I am also of opinion that all bodies 
have some degree of cohesion, as I also believe that there are 
none which do not have some fluidity, and whose cohesion is 
not capable of being overcome ; so that, in my opinion, the 
atoms of Epicurus, 1 whose hardness is supposed to be invinci- 
ble, cannot occur any more than the subtile, perfectly fluid 
matter of the Cartesians. But this is riot the place to justify 
this opinion or to explain the rationale of cohesion. 

Ph. The perfect solidity of bodies seems to be justified by 
experiment. For example, water incapable of yielding, passed 
through the pores of a hollow globe of gold, in which it was 
confined, when this globe was put under pressure in Florence. 

Th. [There is something to be said as to the inference which 
you draw from this experiment, and from what happened in 
the case of the water. The air as well as the water is a body, 
which is compressible at least ad sensum, and those who would 
maintain a complete rarefaction and condensation will say that 
water is already too compressed to yield to our machines, as 
air very much compressed would resist also a further compres- 
sion. I admit, however, on the other hand, that if any slight 
change should be noticed in the volume of the water, it might 
be ascribed to the air which is enclosed in it. Without enter- 
1 Epicurus, December, 342, or January, 341-270 B.C. — Tr. 



ch. iv] ON HUMAN UNDERSTANDING 127 

ing now into the discussion whether pure water is not itself 
compressible, as it is found that it is dilatable when it evapo- 
rates, I am, nevertheless, decidedly of the opinion of those who 
believe that bodies are perfectly impenetrable, and that there 
is, save in appearance, neither condensation nor rarefaction. 
But this kind of experiment is as little capable of proving this 
as the tube of Torricelli l or the machine of Guerike 2 are suffi- 
cient to prove a perfect vacuum. 3 

§ 5. Ph. If the body were strictly capable of rarefaction 
and compression, it might change in volume or extension, but 
that not being so, it will be always equal to the same space ; 
and, moreover, its extension will be always distinct from that 
of space. 

Th. [The body might have its own extension, but it does not 
thereby follow that it would be always determinate or equal 
to the same space. Nevertheless, although it may be true that 
in the conception of body something besides space is conceived 
of, it does not thereby follow that there are two extensions — 
that of space and that of body ; for it is as when in conceiving 
several things at once, one conceives something besides the 
number, viz. : res numerates; and, moreover, there are not two 
multitudes, the one abstract — i.e., that of number; the other 
concrete — i.e., that of the things enumerated. Likewise one 
can say that it is not necessary to think of two extensions — 
the one abstract, of space, the other concrete, of body, the con- 



1 Evangelista Torricelli, 1608-1647, a celebrated Italian physicist and 
matician, the inventor of the mercurial barometer, long called the " Torricel- 
lian tube." He had a controversy with Roberval {vid. ante, p. 107 and note) as 
to the discovery of the quadrature of the cycloid. Torricelli found the area of 
the curve, and furnished the demonstration of it, which he published in a tract, 
De motu gravium naturaliter accelerate in his Opera geometrica, Florence, 
1644.— Tr. 

2 Otto von Guerike, 1602-1686, a German physicist, who devoted himself 
especially to experimenting upon the vacuum, and who, after many attempts, 
finally, in 1654, hit upon an air machine, which enabled, him to undertake 
a series of experiments upon the different effects of vacuum. His labors and 
principal observations have been published under the title, Evperimentanova, 
ut vocant, Magdeburgica, de vacuo spatio, etc., Amsterdam, 1672. — Tr. 

3 Descartes maintained the impossibility of a vacuum. Cf. Prin. Philos., II., 
§ 16; English translation by John Veitch, LL.D., The Method, Meditations, 
and Selections from the Principles of Descartes, etc., 8th ed., p. 241, Edin- 
burgh : William Blackwood & Sons, 1881 ; also vid. ante, p. 16, and the fifth 
letter to Samuel Clarke, § 34, Gerhardt, Vol. 7, p. 396; Erdmann, p. 766, b; 
translation, Duncan, Philos. Works of Leibnitz, p. 262. — Tr. 



128 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

crete existing as such only through the abstract. And as 
bodies pass from one part of space to another — i.e., change 
order among themselves — things also pass from one part of 
the order or of a number to the other, when, for example, the 
first becomes the second and the second the third, etc. In 
fact, time and space are only kinds of order, 1 and in these 
orders the vacant place (which in relation to space is called 
vacuum), if there were any, would show the possibility only of 
that which is lacking together with its relation to the actual. 

Ph. I am nevertheless very glad that you agree with me 
that matter does not change in volume. But you seem to go 
too far, sir, in not recognizing two extensions, and you re- 
semble the Cartesians, who do not distinguish space from mat- 
ter. 2 Now it seems to me that if a class is found who, not 
having these distinct ideas (of space and of solidity which fills 
it), blends them and makes of the two one only, we cannot see 
how these persons can converse with others. They are like a 
blind man who, when another man speaks to him of scarlet, 
thinks it resembles the sound of a trumpet. 

Th. [But I hold at the same time that the ideas of exten- 
sion and solidity, like that of scarlet-color, do not consist in an 
I lenov) not what. 3 I distinguish extension and matter, contrary 

1 Cf. Letter to Des Bosses, June 16, 1712, Gerhardt, Vol. 2, p. 450 ; Erdmann, 
p. 682, b: " Spatium fit ordo coexistentium pliBenomenorum, ut tempus succes- 
sivorum," i.e. " Space is the order of co-existing, as time of successive phe- 
nomena " ; also the letters to Clarke, Gerhardt, Vol. 7, pp. 345 sq. ; Erdmann, 
pp. 746 sq., translation, Duncan, Philos. Works of Leibnitz, pp. 238 sq.; Kant, 
Kritik d. r. Vemunft, Erst. Th., Absch. 1 und 2, §§ 2-7, and translations of 
Max Midler, and Watson in The Philosophy of Kant, as contained in extracts 
from his oivn writings. New York: Macmillan & Co., 1888. — Tr. 

2 Cf. Descartes, Prin. Philos. II., §§ 8-15; Veitch's translation, pp. 236-240. 
— Tr. 

3 Leibnitz's expression is "un je ne say quoi." Schaarschmidt trans- 
lates it"ein undenkbares Etwus." It seems to be equivalent to an indef- 
inite somewhat which is the ultimate essence of things, and which is the 
cause of, and by differentiation becomes, the particidar. Leibnitz, then, 
means to say that the ideas of extension and solidity are distinct. Cf. John 
Dewey, Ph.D., Leibniz's New Essays concerning the Human Understanding, 
a Critical Exposition, p. 134. As applied to personal beings, it seems to be 
equivalent to the " unconscious presentations" — i.e. "the dark side of the 
soul-life," " the proper basis of Individuality." " Genius, disposition, feeling, 
are the terms by which a later time has designated what Leibnitz calls the 
je ne sais quoi, whereby every one is preformed by nature to something par- 
ticular " (" Ganz wie bei dem blossen Monaden ihre individuelle Beschaffeu- 
heit in dem Momente der Schranke, der materia prima, lag, ganz so werden 



en. v] ON HUMAN UNDERSTANDING 129 

to the view of the Cartesians. Still I do not believe that there 
are two extensions ; and since those who dispute over the dif- 
ference between extension and solidity are agreed on several 
truths upon this subject and have some distinct notions, they 
can find therein the means of extricating themselves from their 
disagreement ; thus the assumed difference upon ideas ought 
not to serve as a pretext for eternal disputes, although I know 
that certain Cartesians, otherwise very able, are accustomed 
to intrench themselves in the ideas which they pretend to 
have. But if they would avail themselves of the means which 
I have before given for recognizing ideas true and false, and 
of which we shall speak also in the sequel, they would retire 
from a position which is not tenable. 



CHAPTEE V 

OF SIMPLE IDEAS WHICH COME BY DIFFERENT SENSES 

Ph. The ideas, the perception of which comes to us from 
more than one sense, are those of space, or extension, or fig- 
ure, of motion and rest. 

Th. [The ideas which are said to come from more than one 
sense, like those of space, figure, motion, rest, are rather from 
common-sense, that is to say, from the mind itself, for they 
are ideas of the pure understanding, but related to externality, 
and which the senses make us perceive ; they are also capable 
of definition and demonstration.] 

kier diese unbewussten Vorstellungen, d. h. wird die dunkle Seite des Seelen- 
lebens, als der eigentliche Grand der Individuality bestimmt. Genius, 
Gemiith, Gefiihl sind die Worte, mit denen eine spatere Zeit das bezeicbnet 
hat, was Leibnitz das je ne sais qxioi nennt, wodurch Jeder von Natur zu 
etwas Besonderem praformirt ist." Erdmann, Grundriss d. Gesch. d. Philos., 
3te Auflage 2te Bd. § 288, 5, s. 161. Berlin, 1878 ; English translation, Vol. 2, 
p. 191, London: Swan Sonnenschein & Co., 1889). Of. also Leibnitz, New 
JEssays, Preface, vid. ante, pp. 47 sq., Book II., chap. 1, § 15, Th., sq., and 
Erdmann's exposition of the same, op. cit., s. 160, 161. Also Professor Dewey's 
most excellent work cited above. — Tr. 



130 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

CHAPTER VI 

OF SIMPLE IDEAS WHICH COME BY REFLECTION 

Ph. The simple ideas which come by reflection are the ideas 
of the understanding and. of the will [for we ourselves per- 
ceive them in reflecting upon ourselves.] 

Th. [It is doubtful if all these ideas are simple, for it is 
clear, for example, that the idea of the will includes that of 
the understanding, and that the idea of motion contains that 
of figure. 

CHAPTER VII 

OF IDEAS WHICH COME BY SENSATION AND REFLECTION 

§ 1. Ph. There are some simple ideas which make themselves 
perceived in the mind by all the avenues of sensation and by 
reflection also — viz.: pleasure, pain, power, existence, unity. 

Th. [It seems that the senses cannot convince us of the exist- 
ence of sensible things without the aid of the reason. Thus I 
should think that the idea 1 of existence comes from reflection. 
That of power also and of unity come from the same source, 
and are of a wholly different nature from the perceptions of 
pleasure and pain.] 

CHAPTER VIII 

OTHER CONSIDERATIONS UPON SIMPLE IDEAS 

§ 2. Ph. What shall we say of ideas of privative qiialities? 
It seems to me that the ideas of rest, darkness, and cold are as 
positive as those of motion, light, and heat. Nevertheless, in 
proposing these privations as the causes of privative ideas I 
follow the common view ; but in the main it will be difficult 
1 The French is "la consideration de l'existence." — Tr. 



ch. vm] ON HUMAN UNDERSTANDING 131 

to determine whether there is really any idea which arises 
from a privative cause until it has been determined whether 
rest any more than motion is a privation. 

Th. [I had not believed that we could have reason to doubt 
the privative nature of rest. It suffices it that motion in the 
body be denied, but it does not suffice for motion to deny rest, 
and it is necessary to add something more to determine the de- 
gree of motion, since it receives materially more or less, while 
all rest is equal. It is another thing when we speak of the 
cause of rest, which must be positive in the secondary 1 matter 
or mass. I should furthermore regard the very idea of rest as 
privative — i.e., that it consists only in negation. It is true 
that the act of denial is positive.] 

§ 9. Ph. The qualities of things being the faculties they have 
of producing in us perception of ideas, it is well to distinguish 
these qualities. They are primary and secondary. Extension, 
solidity, figure, number, mobility are the original qualities 
inseparable from body which I call primary. § 10. But I call 

1 Leibnitz constantly distinguishes between primary and secondary matter. 
Primary matter is the primitive passive power belonging to each separate 
being as such, by which it is distinguished from God and in which is grounded 
the possibility of representing itself as different. It is essential to and insepa- 
rable from the entelechy, or principle of activity, which it completes, the two 
united producing the perfect substance or monad. By itself it is a pure 
abstraction or potentiality, and not a substance. It is equivalent to confused 
ideas, thus to an imperfect manifestation or phenomenon of spirit — since all 
matter is ultimately spirit or has its final reason or source in spirit — but a 
potentiality of spirit capable sometime of realizing perfectly all its intrinsic, 
but now latent, activity. Secondary matter is a mass resulting from the union 
of many monads or complete substances, each having its own primary matter 
and its own entelechy, with their derived forces, activities, receptivities. It 
is not, however, a substance ; and its extension resulting from the union of 
non-extended simple substances is only phenomenal, though not on that 
account unreal, being due to our confused perception, and consisting in the 
impenetrability, resistance, or inertia of the monad on its passive side; an 
extension which will disappear when the activity of the monad becomes pure 
and perfect. Cf. Letters to Tolomei, Dec. 17, 1705, Gerhardt, Vol. 7, pp. 467- 
468 ; Des Bosses, March 11, Oct. 16, 1706, March 16, 1709, Gerhardt, Vol. 2, 
pp. 304, 324, 368 ; Erdmann, pp. 435, 440, 456 ; Be anima brvtorvm, 1710, G. 7, 
328 ; E. 463 ; Letters to Rud. Christ. Wagner, June 4, 1710, G. 7, 528, E. 465 ; 
translation, Duncan, Philos. Works of Leibnitz, p. 190 sq. ; Bierling, Aug. 12, 
1711, G. 7, 500-502, E. 677-678 ; Remond, Nov. 4, 1715, G. 3, 656-660 ; E. 735- 
737 ; Feb. 11, 1715, § 4 (reply to Remond's fourth difficulty stated in his letter to 
Leibnitz, Jan. 9, 1715), G. 3, 636, E. 725 ; also the writing dated July, 1714, and 
first published by Gerhardt, 3, 622-624. Cf. also Erdmann, Grund. d. Gesch. d. 
Philos., 3d ed., § 288, 2, 3 ; Dewey, Leibnitz, New Essays, chaps. 7 and 8. — Tr. 



132 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

secondary qualities the faculties or powers of bodies to produce 
certaiu sensations in us, or certain effects in other bodies, as 
the fire, for example, produces a certain effect in the wax when 
melting it. 

Th. [I think we can say that when the power is intelligible, 
and can be distinctly explained, it should be reckoned among 
the primary qualities ; but when it is only sensible and 'gives 
only a confused idea, it should be put among the secondary qual- 
ities.'] 

§ 11. Ph. These primary qualities show how bodies act upon 
one another. Now, bodies act only by impulse, at least so far 
as we can conceive the process, for it is impossible to under- 
stand how bodies can act upon what they do not touch, which 
is equivalent to imagining that they can act where they are 
not. 

Th. [I am also of the opinion that bodies act only by impulse. 
Yet, there is some difficulty in the proof of what I have just 
heard ; for attraction sometimes occurs without contact, and we 
can touch and draw without any visible impulse, as I have 
shown above * in speaking of hardness. In the case of the atoms 
of Epicurus, the one part pushed would draw the other with 
it, and would touch it in putting it in motion without impulse. 
And in the case of attraction between contiguous things we 
cannot say that the one which draws with itself acts where it 
is not. This reason would militate only against attractions 
from a distance, as would be the case in reference to what are 
called vires centripetce advanced by some scholars.] 

§ 13. Ph. Now, certain particles, striking our organs in a cer- 
tain way, cause in us certain sensations of colors or tastes or 
other secondary qualities which have the power of producing 
these sensations. And it is no more difficult to conceive that 
G-od can attach such ideas (as that of heat) to motions, with 
which they have no resemblance, than it is difficult to conceive 
that he has attached the idea of pain to the motion of a piece 
of iron which divides our flesh ; which motion the pain in no 
manner resembles. 

Th. [It is not necessary to suppose that ideas like those of 
color or of pain are arbitrary and without relation or natural 
connection with their causes ; it is not the custom of God to 
1 Of. Bk. II., Chap. 4, § 4, Th., ante, p. 125, sq.—Tr. 



ch. vin] ON HUMAN UNDERSTANDING 133 

act with so little order and reason. I should rather say that 
there is a kind of resemblance, not complete and, so to speak, 
in terminis, but expressive, or a kind of orderly relation, as an 
ellipse, and even a parabola or hyperbola resemble in some 
sense the circle of which they are a projection upon a plane, 
since there is a certain exact and natural relation between 
what is projected and the projection which is made, each point 
of the one corresponding by a certain relation to each point of 
the other. This the Cartesians do not sufficiently consider, 
and for once you have deferred to them more than has been 
customary with you, and without reason for so doing.] 

§ 15. Ph. I tell you what appears to me, and the appear- 
ances are that the ideas of the primary qualities of bodies 
resemble these qualities, but the ideas produced in us by the 
secondary qualities resemble them in no way. 

Th. [I have just shown how there is resemblance or exact 
relation in respect to the secondary as well as the primary 
qualities. It is certainly reasonable that the effect correspond 
to its cause ; and how assert the contrary, since you know dis- 
tinctly neither .the sensation of blue (for example) nor the 
motions which produce it ? It is true that pain does not 
resemble the motion of a pin, but it may very well resemble 
the motions which this pin causes in our body, and represent 
these motions in the soul, as I have no doubt it does. It is 
also for this reason that we say that the pain is in our body 
and not that it is in the pin ; but we say that the light is in the 
fire, because there are in the fire motions which are not dis- 
tinctly sensible apart from it, but whose confusion or con- 
junction becomes sensible, and is represented to us by the idea 
of light. 

§ 21. Ph. But if the relation between the object and the 
sensation be natural, how can it be, as we notice in fact, that 
the same water may appear warm to one hand and cold to the 
other ? which shows that the heat is no more in the water 
than the pain is in the pin. 

Th. [This proves all the more that heat is not a sensible 
quality or power of making itself felt absolutely all at once, 
but that it is relative to the suitable organs ; for a particular 
motion in the hand may be mixed with it and change its appear- 
ance. Light, furthermore, does not make itself evident to 



134 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

badly constituted eyes, and when they are themselves filled 
with a great light, they are insensible to a less. Even the 
primary qualities (according to our classification) — for ex- 
ample, unity and number — may not appear as they should ; 
for, as Descartes has already stated, a globe touched by the 
fingers in a certain way appears double, and mirrors or glasses 
cut in facets multiply the object. It does not then follow that 
what does not always appear the same is not a quality of the 
object, and that its image does not resemble it. And as for 
the heat, when our hand is very warm, the medium heat of the 
water does not make itself felt, and modifies rather that of 
the hand, and consequently the water appears to us cold ; as 
the salt water of the Baltic Sea mixed with the water of the 
Sea of Portugal 1 would lessen its specific saline quality, 
although the former be itself salt. Thus, in any case, we can 
say that the heat belongs to the water of a bath, although it 
may appear cold to any one, as honey is called absolutely 
sweet, and silver white, although the one appears bitter, the 
other yellow to some diseased persons, for the classification is 
made upon the basis of the most common (conditions) ; and 
yet it remains true that, when the organ and the medium are 
constituted as they should be, the internal motions and the 
ideas which represent them to the soul resemble the motions 
of the object which cause color, heat, pain, etc., or, what is 
here the same thing, express it by means of a relation suffi- 
ciently exact, although this relation does not distinctly appear 
to us, because we cannot disentangle this multitude of small 
impressions either in our soul or our body or in what is with- 
out. 

§ 24. Ph. We consider the qualities which the sun has of 
blanching or melting wax or hardening mud only as simple 
powers, without thinking of anything in the sun correspond- 
ing to this blanching, softness, or hardness ; but heat and light 
are commonly regarded as real qualities of the sun. Properly 
considered, however, these qualities of light and heat which in 
me are perceptions are not in the sun in any other manner 
than the changes produced in the wax when it is blanched or 
melted. 

1 Obsolete name for that part of the Atlantic which washes the coast of 
Portugal.— Tr. 



en. ix] ON HUMAN UNDERSTANDING 135 

Th. [Some have pushed this doctrine so far that they have 
desired to persuade us that if any one could touch the sun he 
would find there no heat. The counterfeit sun which makes 
itself felt in the focus of a mirror or a burning-glass may disa- 
buse people of this notion. But as to the comparison between 
the power of heating and that of melting, I dare affirm that if 
the melted or blanched wax had feeling, it would feel some- 
thing similar to what we feel when the sun warms us, and 
would say, if it could, that the sun is warm, not because its 
whiteness resembles the sun — for when faces are tanned in 
the sun their brown color should likewise resemble it — but 
because there are in the wax motions which are related to 
those in the sun which cause them ; its whiteness may come 
from another cause, but not the motions which it has had in 
receiving it (whiteness) from the sun.] 



CHAPTER IX 

OF PERCEPTION 

§ 1. Ph. Come we now to the ideas of reflection in particu- 
lar. Perception is the first faculty of the soul which is occu- 
pied with our ideas. It is also the first and simplest idea 
which we receive by reflection. Thought signifies often the 
mind's working upon its own ideas, when it acts and considers 
a thing with a certain degree of voluntary attention : but in 
what we call perception the mind is ordinarily purely passive, 
not being able to avoid perceiving what it actually perceives. 

Th. [We might perhaps add that the animals have percep- 
tion, and that it is not necessary that they have thought, that 
is to say, that they have reflection or what may be its object. 
We ourselves also have minute perceptions of which we are not 
conscious in our present state. It is true that we might very 
well perceive them ourselves, and reflect upon them, if we 
were not turned aside by their multitude, which distracts our 
mind, or if they were not effaced, or rather obscured, by 
greater ones. 

§ 4. Ph. I admit that when the mind is strongly occupied 



136 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

in contemplating certain objects it does not perceive in any- 
way the impression which certain bodies make upon the organ 
of hearing, although the impression may be quite strong ; but 
no perception arises therefrom if the soul takes no cognizance 
thereof. 

Th. [I should prefer to distinguish between perception and 
conscious7iess (s J appercevoir) } The perception of light and 
color, for example, of which we are conscious, is composed of 
many minute perceptions, of which we are not conscious ; and 
a noise which we perceive, but of which we take no notice, 
becomes apperceptive by a little addition or increase ; for if 
what precedes make no impression upon the soul, this little 
addition would also make none, and the whole would make 
no more. I have already touched upon this point (Ch. II, 2 of 
this book, §§ 11, 12, 15, etc.)]. 

§ 8. Ph. It is proper to remark here that the ideas which 
arise from sensation are often altered by the mental judgment 
of grown persons without their perceiving the fact. A flat 
circle with various light and shade represents the idea of a 
globe of uniform color. But, as we are accustomed to distin- 
guish the images of bodies and the changes of the reflections 
of light according to the figures of their surfaces, we put in the 
place of what appears to us the cause the image itself, and 
confuse the judgment with the appearance. 

Th. Nothing is truer, and this it is which gives to painting 
the means of deceiving us by the artifice of a very extended 
perspective. When bodies have flat surfaces, they can be rep- 
resented without employing shadows by giving only their con- 
tours and by simply making pictures after the fashion of the 
Chinese, but better proportioned than theirs. The same 

1 Of. Leibnitz, Principes de la nature et de la grace fonde's en raison, § 4. 
" It is well to make a distinction between the perception, which is the internal 
condition of the monad representing external things, and apperception, which 
is consciousness or the reflective knowledge of this internal state; the latter 
not being given to all souls, nor at all times to the same soul." For the 
entire piece, which is a brief statement of his philosophical system prepared 
by Leibnitz himself, with the greatest care, about 1714, cf. Gerhardt, Vol. 6, 
pp. 598-606; Erdmann, pp. 714-718; translation, Duncan, Philos. Works of 
Leibnitz, pp. 209-217, and note 66, p. 387 op. cit. Also Hamilton's Reid, 8th 
ed., Vol. 2, p. 877, note, and Krauth-Fleming, Vocab. Philos., ed. of 1877, 
articles "Apperception," p. 38, "Consciousness," pp. 109-113,613, "Percep- 
tion," pp. 373-374, 807-809, "Perceptions (Obscure)," pp. 374-376.— Tr. 

2 This should be chap. 1, I think.— Tr. 



ch. ix] ON HUMAN UNDERSTANDING 137 

custom is observed in designing medals, in order that the 
draughtsman may be less likely to depart from the precise 
form of the antique. But we cannot distinguish exactly by 
means of the design the interior of a circle from the interior of 
a spherical surface bounded by this circle without the aid of 
shadows, the interior of each having neither points distin- 
guished nor distinguishing features, although there is, however, 
a great difference which ought to be indicated. Desargues * 
has accordingly given precepts upon the force of tints and 
shades. When, then, a painting deceives us there is a double 
error in our judgments; for first we put the cause for the effect, 
and think we see immediately the cause of the image, in which 
we resemble a little a dog who barks at a mirror ; for, properly 
speaking, we see only the image, and we are affected only by 
the rays of light. And since the rays of light require time (how- 
ever little it be), it is possible for the object to be destroyed in 
this interval, and for it no longer to exist when the ray reaches 
the eye, and that which no longer exists cannot be the object 
present to the sight. In the second place, we further deceive 
ourselves when we put one cause for another, and think that 
what comes only from a flat picture is derived from a body, so 
that in this case there is in our judgments all at once a me- 
tonymy and a metaphor; for even the figures of rhetoric pass 
into sojohisms when they impose on us. This confusion of the 
effect with the cause, whether true or false, often enters into 
our judgments, moreover, upon other things. Thus we feel 
our bodies, or what touches them, and we move our arms by 
means of an immediate physical influence, which we think 

i Gaspard Desargues, 1593-1662, a French geometer and engineer, a friend 
of Descartes, Gassendi, Pascal, and Roberval, who wrote on the application of 
geometry to the arts as well as on geometry itself. These writings have been 
lost and their titles are known only through the engraver Bosse. Of his 
Methode universelle de mettre en perspective des objects donnes reellement, 
ou en devis, avec leurs proportions, mesures, eloignments, sans employer 
aucun point qui soit hors du champ de I'ouvrage, 1630 or 1636, Descartes thus 
speaks in a letter to Mersenne ("written toward the end of April, 1637," 
according to Cousin, (Euvres de Descartes, Vol. 6, pp. 250-256, Paris : 1824- 
1826), " Je n'ai recu que depuis peu de jours le petit livre in folio, qui traite 
de la perspective: il n'est pas a desapprouver, outre que la curiosite et la 
nettete du langage de son auteur sont a estimer," I received only a few 
days ago the little book in folio treating of perspective : it is not to be con- 
demned ; further the exactness and perspicuity of the author's language are to 
be admired. — Tr. 



138 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

constitutes the connection of the soul with the body, while in • 
truth we feel and change in that way only what is in us. 

Ph. I will at this time propose to you a problem which the 
learned Mr. Molyneux, 1 who employs so profitably his excel- 
lent genius in the promotion of the sciences, communicated to 
the illustrious Mr. Locke. Here it is nearly in his own 
terms : Suppose a man blind from birth, now grown up, who 
has learned to distinguish by touch a cube from a globe of the 
same metal, and almost of the same size, so that when he 
touches the one or the other he can tell which is the cube and 
which the globe. Suppose that the cube and the globe being 
placed upon the table, this blind man comes to enjoy his sight. 
The question is, if in seeing them without touching them he 
could distinguish them, and tell which is the cube and which 
the globe. I pray you, sir, tell me what is your opinion upon 
the matter. 

Th. I ought to give some time to thought upon this ques- 
tion, which appears to me quite curious : but since you press 
me for an immediate reply, I would venture to say between 
ourselves that I think that supposing the blind man knows 
that these two figures which he sees are those of the cube and 
the globe, he could distinguish them and say, without touch- 
ing, This is the globe, this the cube. 

Ph. I fear lest it "may be necessary to put you in the crowd 
of those who have failed to answer Mr. Molyneux ; for he sent 
word in the letter which contained this question, that, having 
proposed it upon the occasion of Mr. Locke's Essay on Under- 
standing to different persons of very penetrating minds, he 
had found scarcely one among them who at once gave such a 
reply upon that point as he thinks should be made, although 
they were convinced of their error after having heard his 
reasons. The reply of this penetrating and judicious author 
is negative ; for (he adds) while this blind man has learned 
by experience of some kind the globe and the cube as they 
affect his touch, he does not, however, yet know that what 
affects the touch in such or such manner must strike the eyes 

1 William Molyneux, 1656-1698, an eminent mathematician. He founded in 
Dublin, in January, 1684, a Philosophical Society on the model of the Royal 
Society at London. His principal work, Dioptrica Nova, in two parts, was 
published at London in 1692-1709, in 4to. — Tr. 



en. ix] ON HUMAN UNDERSTANDING 139 

in such or such manner, nor that the projecting angle of the 
cube, which presses his hand in an unequal manner, must 
appear to his eyes as it appears in the cube. The author of 
the Essay declares himself at once of the same opinion. 

Th. Perhaps Mr. Molyneux and the author of the Essay are 
not so far from my opinion as at first appears, and the reasons 
for their view, contained apparently in the letter of the for- 
mer, who has employed them with success in order to convince 
men of their error, have been purposely suppressed by the 
latter in order to give more exercise to the minds of his 
readers. If you will weigh my reply, you will find, sir, that 
I have placed therein a condition which can be considered as 
comprised in the question — viz. : that the question is that of 
distinguishing alone, and that the blind man knows that the 
two figured bodies, which he should distinguish, are there, and 
that thus each of the appearances which he sees is that of the 
cube or that of the globe. In this case it appears to me 
beyond doubt that the blind man who ceases to be such can 
distinguish them by the principles of reason, united with that 
sense-knowledge with which touch has before furnished him. 
For I do not speak of that which he will do perhaps in fact 
and immediately, dazzled and confused by the novelty, or from 
some other cause little accustomed to draw inferences. The 
basis of my view is that in the globe there are no points dis- 
tinguished by the side of the globe itself, all there being level 
and without angles, while in the. cube there are eight points 
distinguished from all the others. If there were not this 
means of discerning the figures, a blind man could not learn 
the rudiments of geometry by touch. But we see that those 
born blind are capable of learning geometry, and have indeed 
always certain rudiments of a natural geometry, and that 
most often geometry is learned by sight alone, without the 
use of touch, as indeed a paralytic or other person to whom 
touch has been almost denied might and even must do. 
And these two geometries — that of the blind man and that of 
the paralytic — must meet and agree, and indeed return to the 
same ideas, although there are no common images. This again 
shows how necessary it is to distinguish images from exact 
ideas, which consist in definitions. It would really be very 
interesting and instructive to make a complete examination of 



140 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

the ideas of a man born blind, to understand the descriptions 
he makes of figures. For he may come to this, and he may- 
even understand the doctrine of optics, so far as it is depend- 
ent upon distinct and mathematical ideas, although he could 
not attain to a conception of clair-confus, that is to say, the 
image of light and of colors. This is why a certain one born 
blind, after having attended lessons in optics, which he 
appeared fully to understand, replied to some one who asked 
him what he thought light was, that he thought it must be 
something pleasant like sugar. It would likewise be very 
important to examine the ideas which a man born deaf and 
dumb may have of things not figured, whose description we 
usually have in words, and which he must have in a manner 
wholly different from, though it may be equivalent to ours, as 
Chinese writing is in fact equivalent to our alphabet, although 
it is infinitely different, and might appear to have been in- 
vented by a deaf man. I learn, through the favor of a great 
prince, of one born deaf and dumb in Paris, whose ears have 
at last attained to the performance of their function, that he 
has now learned the French language (for it is from the court 
of France that he was summoned not long since), and that he 
could say very curious things about the conceptions he had in 
his former condition and about the change of his ideas when 
he commenced to exercise the sense of hearing. These per- 
sons born deaf and dumb can go farther than we think. 
There was one in Oldenburg in the time of the last Count 
who became a good painter, and showed himself very rational 
in other respects. A very learned man, a Breton by nation, 
told me that at Blainville, about ten leagues from Nantes, 
belonging to the Duke of Rohan, there was, about 1690, a 
poor man, who lived in a hut near the castle outside of the 
town, who was born deaf and dumb, and who carried letters 
and other things to the town and found the houses, following 
some signs which the persons accustomed to employ him 
made him. Finally the poor man became blind also, but did 
not give up rendering some service and carrying letters into 
the town to whatever place they indicated to him by touch. 
He had a board in his hut which, extending from the door to 
the place where his feet were, informed him by its motion 
when any one entered his house. Men are very negligent in 



en. ix] ON HUMAN UNDERSTANDING 141 

not obtaining an exact knowledge of the modes of thought 
of such persons. If he no longer lives, there is probably 
some one in the vicinity who could still give some information 
respecting him, and make us understand how they showed him 
the things he was to do. But to return to what the man born 
blind, who begins to see, would think of the globe and the 
cube, seeing them without touching them, I reply that he will 
distinguish them, as I have just said, if any one informs him 
that the one or the other of the appearances or perceptions 
which he has of them belongs to the cube or to the globe ; 
but, without this previous instruction, I admit that he will 
not at first venture to think that the kinds of pictures which 
they make of themselves in the depths of his eyes, and which 
might come from a flat picture upon the table, represent the 
bodies, until touch convinces him of the fact, or until, by 
force of reasoning upon the rays of light according to optics, 
he understands by the lights and shades that there is a some- 
thing which arrests these rays of light, and that it must be 
exactly what remains for him in touch, which result he will 
finally reach when he sees this globe and this cube revolve, 
and change the shadows and the appearances in accordance 
with the motion, or even when, these two bodies remaining at 
rest, the light which illumines them changes its place, or his 
eyes change their position. For these are about the means 
we have of distinguishing from afar a picture or a perspec- 
tive, which represents a body, from the body itself. 

§ 11. Ph. [Let us return to perception in general.] It dis- 
tinguishes animals from inferior beings. 

Th. [I am inclined to the belief that there is some percep- 
tion and appetition also in the plants, because of the great 
analogy which exists between plants and animals ; and if, as 
is commonly supposed, there is a vegetable soul, it of necessity 
has perception. Yet I do not cease to attribute to mechanism 
all that takes places in the bodies of plants and animals, 
except their first formation. Thus I agree that the move- 
ment of the plant called sensitive arises from mechanism, and 
I do not approve of having recourse to the soul when the 
question is that of explaining the detail of the phenomena 
of plants and animals.] 

§ 14. Ph. It is true that for myself, indeed, I cannot help 



142 LEIBNITZ'S CRITIQUE OF LOCKE [bk. 11 

believing that even in those kinds of animals which are like 
the oysters and mussels there is some feeble perception ; for 
quick sensations would serve only to discommode an animal 
which is constrained to live always in the place where chance 
has put it, where it is watered with water, cold or warm, pure 
or salt, according as it comes to it. 

Th. [Very well, I also believe that we can say almost as 
much of plants ; but in man's case, his perceptions are accom- 
panied with the power of reflection, which passes to the act 
when there is any occasion. But when he is reduced to a state 
in which he is as it were in a lethargy and almost without 
feeling, reflection and consciousness cease, and universal truths 
are not thought of. But the innate and acquired faculties and 
dispositions, and even the impressions which are received in 
this state of confusion, do not cease on that account, and are 
not effaced, though they are forgotten. They will even have 
their turn one day in contributing to some notable result, for 
nothing is useless in nature ; all confusion must develop 
itself; the animals even, having attained to a condition of 
stupidity, ought some day to return to perceptions more ele- 
vated ; and, since simple substances always endure, we must 
not judge of eternity by a few years.] 



CHAPTEB X 

OF RETENTION 

§§ 1, 2. Ph. The other faculty of the mind, by which it 
advances farther toward the knowledge of things than by sim- 
ple perception, is that which I call retention, which conserves 
the knowledge received by the senses or by reflection. Reten- 
tion works in two ways : in actually conserving the present 
idea, which I call contemplation; and in preserving the power 
to bring them again before the mind, and this is what is called 
memory. 

Th. [One retains also and contemplates innate knowledge, 
and very often one cannot distinguish the innate from the 
acquired. There is also a perception of images — either those 



en. xi] ON HUMAN UNDERSTANDING 143 

which have already existed for some time, or those which are 
formed anew in us.] 

§ 2. Ph. But you believe with us that these images or ideas 
cease to be anything as soon as they are not actually matters 
of consciousness ; and that to say that there are ideas reserved 
in the memory means at bottom only that the soul has in some 
instances the poicer of reviving the perceptions it has already 
had with a feeling which at the same time convinces it that it 
has previously had these kinds of perceptions. 

Th. [If ideas were only forms or modes of thoughts, they 
would cease with them ; but you yourself have admitted, sir, 
that they are internal objects, and in this way can subsist. 
And I am astonished that you can always be satisfied with 
these naked powers or faculties, which you would apparently 
reject in the scholastic philosophers. It would be necessary 
to explain a little more distinctly in what this faculty consists 
and how it is exercised ; and that would make known that 
there are dispositions which are the remains of past impres- 
sions in the soul as well as in the body, but of which we are 
conscious only when the memory finds some occasion for them. 
And if nothing restored past thoughts, as soon as we no longer 
think of them, it would be impossible to explain how the 
memory can preserve them ; and to recur for this purpose to 
this naked faculty is to speak nowise intelligibly. 



CHAPTEE XI 

OF DISCERNMENT OR THE FACULTY OF DISTINGUISHING IDEAS 

§ 1. Ph. Upon the faculty of distinguishing ideas depends 
the evidence and certainty of several propositions which pass 
for innate truths. 

Th. I admit that to think of these innate truths and to 
unravel them discernment is necessary ; but they do not on 
that account cease to be innate.] 

§ 2. Ph. Now, vivacity of mind consists in recalling 
promptly ideas ; but judgment in representing them clearly 
and distinguishing them exactly. 



144 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

Tli. [Perhaps each is vivacity of imagination, and judg- 
ment consists in the examination of propositions according to 
reason.] 

Ph. [I am not averse to this distinction of mind and judg- 
ment. And sometimes there is judgment in not employing it 
too much. For example : to examine certain witty thoughts 
by the severe rules of truth and good reasoning is in a certain 
sense an insult. 

Th. [This remark is a good one ; witty thoughts must have 
at least some apparent foundation in reason, but it is not 
necessary to examine them minutely with too much scrupu- 
lousness, as it is not necessary to look at a picture from a 
position too near it. It is in this, it seems to me, that 
Father Bouhours fails more than once in his Art de penser 
dans les ouvrages d' 'esprit 1 as when he despises this sally of 
Lucan : 2 

Victrix causa diis placuit, seel victa Catoni. 

§ 4. Ph. Another operation of the mind in respect to its 
ideas is the comparison it makes of one idea with another as 
regards extension, degrees, time, place, or some other circum- 
stance ; it is upon this that the great number of ideas com- 
prised under the term relation depends. 

Th. [According to my view, relation is more general than 
comparison, for relations are either of comparison or of concur- 
rence. The first concern the congruity or incongruity (I take 
these terms in a less extended sense) which comprises resem- 
blance, equality, inequality, etc. The second comprise some 
connection, as that of cause and effect, of whole and parts, of 
position and order, etc.] 

§ 6. Ph. The composition of simple ideas, for the purpose 
of making complex ideas, is also an operation of our mind. 
We may refer to this the faculty of extending ideas by uniting 
those of the same kind, as in forming a dozen from several 
units. 

Th. [The one is doubtless as much composition as the 

1 Dominique Bouhours, 1628-1702, one of the ablest masters of the French 
language in the seventeenth century. The title of his work here given follows 
Gerhardt's text. The correct title is: Maniere de Men penser dans les 
ouvrages d' esprit, Paris, 1687. There were several editions. — Tr. 

tPhars. 1,128. — Tr. 



ch. xi] ON HUMAN UNDERSTANDING 145 

other ; but composition of similar ideas is simpler than that of 
different ideas.] 

§ 7. Ph. A dog will nurse young foxes, will play with 
them, and will have for them the same fondness as for her 
own puppies, if they can be made to suck her so long as is 
needful for the milk to spread through their entire body. 
Moreover it does not appear that animals, who have a large 
number of young at once, have any knowledge of their num- 
ber. 

Th. [The love of animals arises from a pleasure which is 
increased by habit. But as for the precise number, men even 
can know the numbers of things only by some skill, as in using 
numerical names in order to count, or figural arrangements 
which make them know at once without counting if anything 
is wanting.] 

§ 10. Ph. Animals do not form abstract thoughts. 

Th. [I agree. They apparently recognize whiteness, and 
notice it in the chalk or the snow ; but this is not yet abstrac- 
tion, for that demands a consideration of what is common, 
separated from what is particular, and consequently there 
enters into it the knowledge of universal truths, which is not 
given to the animals. It is well said also that the animals 
which speak do not use words to express general ideas, and 
that men deprived of the use of speech and of words do not 
cease to invent other general signs. I am pleased also to see 
that you here and elsewhere so well observe the advantages of 
human nature.] 

§ 11. Ph. If animals have some ideas, and are not pure ma- 
chines, as some maintain, we cannot deny that they have reason 
in a certain degree, and, for myself, it appears as evident that 
they reason as that they feel. But it is only upon particular 
ideas that they reason according as their senses represent these 
ideas to them. 

Th. [Animals pass from one imagination to another by the 
connection which they have felt here before ; for example, when 
his master takes a stick, the dog fears a whipping. And in 
many instances children with the rest of mankind proceed 
nowise differently in their passages from thought to thought, 
sense. But I prefer to conform to the received usage m cdhse- 
l 



146 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

crating these terms to man and in limiting them to the knowl- 
edge of some reason of the connection of perceptions, which 
sensations alone cannot give ; their effect being only to canse 
us naturally to expect at another time this same connection 
which we have noticed before, although perhaps the reasons 
are no longer the same, a fact which often deceives those who 
are governed only by the senses.] 

§ 13. Ph. Idiots lack vivacity, activity, and movement in 
the intellectual faculties, whereby they are deprived of the use 
of reason. Madmen seem to be at the opposite extreme, for it 
does not appear to me that these latter have lost the power to 
reason, but having wrongly united certain ideas, they take 
them for truths, and deceive themselves in the same way as 
those who reason justly upon false principles. Thus you will 
see a madman who thinks he is king maintaining by a just 
consequence that he should be served, honored, and obeyed 
according to his rank. 

Tli. [Idiots do not exercise reason, and they differ from some 
stupid persons who have good judgment, but, not having prompt 
conception, they are despised and disturbed as he would be 
who wished to play ombre with persons of distinction and 
thought too long and too often of the part he must take. I 
remember a learned man who, having lost his memory by the 
use of certain drugs, was reduced to this condition, but his 
judgment always appeared. A man wholly mad lacks judg- 
ment on nearly every occasion ; but the vivacity of his imagi- 
nation may make him agreeable. But there are particular 
madmen who make a false supposition at an important point 
in their lives, and reason justly thereupon, as you have well 
said. There is such a man, well known at a certain court, 
who believes himself destined to redress the affairs of the 
Protestants and to bring France to reason, for which purpose 
God caused the greatest personages to pass through his body 
in order to ennoble it ; he desires to marry all the princesses 
he sees to be marriageable, but after having made them holy, 
in order to have a holy progeny who are to rule the land ; 
he attributes all the misfortunes of war to the little attention 
paid to his advice. In speaking with a certain sovereign, 
he takes every necessary measure not to lower his disunity. 



ch. xn] ON HUMAN UNDERSTANDING 147 

himself so well that I have doubted more than once whether 
his madness is not feigned, for he is not inconvenienced by- 
it. However, those who know him more intimately assure me 
that his madness is wholly genuine.] 



CHAPTER XII 

OF COMPLEX IDEAS 

Ph. The understanding bears not a little resemblance to 
a room wholly dark, which has only certain small openings to 
let in from outside exterior and visible images, so that if these 
images, coming to be painted in this dark room, could remain 
there and be placed in order, so that they could be found upon 
occasion, there would be a great resemblance between this 
room and the human understanding. 

Th. [To make the resemblance greater, you should suppose 
that in this room there was a canvas to receive the images, not 
even, but diversified by folds, representing the (kinds of) in- 
nate knowledge ; further, that this canvas or membrane being 
stretched would have a kind of elasticity or power of action, 
and also an action and reaction accommodated as much to the 
past folds as to the newly arrived kinds of impressions. And 
this action would consist in certain vibrations or oscillations, 
such as are seen in a stretched string so touched that it gives 
forth a kind of musical sound. For not only do we receive 
images or outlines in the brain ; but we form besides new ones, 
when we look at complex ideas. Thus the canvas that repre- 
sents our brain is necessarily active and elastic. This com- 
parison would explain tolerably well what passes in the brain ; 
but as for the soul, which is a simple substance or monad, it 
represents without extension these same varieties of extended 
masses and perceives them. 1 ] 

§ 3. Ph. Now complex ideas are either modes or substances 
or relations. 

1 According to the principle of Pre-established Harmony. Cf. Systeme 
nouveau de la nature, etc., 1695, §§ 14, 15 ; Gerhardt, 4, 484, 485 ; Erdmann, 
127, 128; Jacques, 1, 475, 476; translation, Appendix, p. .— Tr. 



148 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

Th. [This division of the objects of our thought into sub- 
stances, modes, 1 and relations is sufficiently to my taste. I be- 
lieve that qualities are only modifications of substances, and 
that the understanding adds thereto the relations. 2 From this 
follows more than you think.] 

Ph. Modes are either simple (as a dozen, a score, which are 
composed of simple ideas of the same kind, i.e. of units) or 
mixed (as beauty), into which enter simple ideas of different 
kinds. 

Th. Perhaps dozen or score are only relations, and are con- 
stituted only in connection with the understanding. Units are 
separate, and the understanding gathers them together how- 
ever dispersed they be. Yet, although relations are from the 
understanding, they are not groundless or unreal. For in the 
first place understanding is the origin of things ; and indeed 
the reality even of all things, simple substances excepted, ulti- 
mately consists only of perceptions of the phenomena of sim- 
ple substances. It is often the same with regard to the mixed 
modes ; i.e. it is necessary to refer them rather to the rela- 
tions.] 

§ 6. Ph. The ideas of substances are certain combinations of 
simple ideas, which are supposed to represent particular and 
distinct things, subsisting by themselves, among which ideas 
the obscure notion of substaiice, which is assumed without 
knowing what it is in itself, is always considered as the first 
and chief. 

Th. [The idea of substance is not so obscure as you think. 
You can know what it ought to be, and what it knows of itself 
in other things ; and indeed the knowledge of the concrete 
always precedes that of the abstract; the hot (thing) rather 
than the heat.] 

§ 7. Ph. In regard to substances there are also two kinds of 
ideas : the one of single substances, like that of a man, or a 
sheep; the other of several substances joined together, as of 
an army of men, or a flock of sheep. These collections form 
also a single idea. 

1 Cf. Descartes, Prin. Philos., I., § 56 ; Veitch's translation, 8th ed., p. 217 ; 
Spinoza, Ethica, Pt. I., Def. 3; Elwes' translation, Vol. 2, p. 46; Locke, Essay, 
Bk. II., chap. 12, § 4, Vol. 1, p. 280 (Bohn's ed.). — Tr. 

2 Cf. Leibnitz, New Essays, Bk. II., chap. 30, § 4. — Tr. 



ch. xin] ON HUMAN UNDERSTANDING 149 

Tli. [This unity of the idea of aggregates is very true ; but 
ultimately you must admit that this collective unity is only a 
congruity or relation, whose ground is in that which is found 
in each of the single substances separately. Thus these beings 
by aggregation have no other completed unity than the mental ; 
consequently their entity also is in some mental shape or phe- 
nomenon, as that of the rainbow.] 



CHAPTER XIII 

QF SIMPLE MODES, AND FIRST OF THOSE OF SPACE 

§ 3. Ph. Space considered with respect to the length which 
separates two bodies is called distance; with respect to length, 
breadth, and depth it may be called capacity. 

Tli. [To speak more distinctly, the distance between two 
fixed things (be they points or extensions) is the length of the 
shortest possible line that can be drawn from one to the other. 
This distance may be considered absolutely or in a certain 
figure which comprises the two distant things. For example, 
the straight line is absolutely the distance between two points. 
But these two points, being in the same spherical surface, the 
distance of these two points in this surface is the length of 
the shortest great arc of a circle, which may be drawn from 
one point to the other. It is well also to notice, that distance 
is not only between bodies, but also between surfaces, lines, 
points. It may be said that the capacity or rather the interval 
between two bodies or two other extensions, or between an 
extension and a point, is the space constituted by all the 
shortest lines which may be drawn between the points of each. 
This interval is filled, except when the two fixed things are 
in the same surface, when the shortest lines between the 
points of the fixed things must also fall in this surface or 
must there be expressly formed.] 

§ 4. Ph. Besides that which is in nature, men have estab- 
lished in their minds the ideas of certain determinate lengths, 
as an inch or a foot. 

Tli. [They cannot do it. For it is impossible to have the 



150 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

idea of a precisely determined length. Yon can neither say 
nor understand by the mind what an inch or a foot is. And 
yon can preserve the meaning of these terms only by real 
measures, which you suppose unchanging, by means of which 
you can always recover them. Thus Mr. Greaves, 1 an Eng- 
lish mathematician, desired to make use of the pyramids of 
Egypt, which have endured a long time and will endure appar- 
ently some time longer, to conserve our measures, by showing 
posterity the propositions 2 which have been sketched in defi- 
nite lengths in one of these pyramids. It is true that a little 
after it was discovered that pendulums serve to perpetuate 
measures (mensuris rerum ad posteros transmittendis) , as Huy- 
gens, 3 Mouton, 4 and Buratini, formerly maistre de monnoye in 
Poland, have demonstrated 5 by showing the proportion of our 
measures of length to that of the pendulum, which beats pre- 
cisely a second (for example), i.e. the 86400th 6 part of a 
revolution of the fixed stars, or of an astronomical day ; and 
Buratini has composed a treatise expressly thereupon, which 

1 John Greaves, 1602-1652, Savilian Professor of Astronomy at Oxford, 
1643-1648. His Pyramidographia, or a Discourse on the Pyramids in Egypt, 
1646. — Tr. 

2 Gerhardt and Erdmann read: "propositions"; Jacques reads: "propor- 
tions " ; Schaarschmidt translates " Vernal tnisse." — Tr. 

3 Christian Huygens, 1629-1695, a Dutch physicist, geometer, and astronomer. 
He discovered the laws of douhle refraction, and was the first to establish on 
a sure foundation the wave theory of light, in his Traite de la lumiere, 
Leyden, 1690. His researches in physical optics constitute his chief claim to 
scientific immortality. His application of the pendulum to regulate the move- 
ment of clocks, arising from his felt need of an exact measure of time in 
astronomical observations, dates from 1656. He published his Description 
de Vhorloge a pendule in 1657, and presented his first "pendulum-clock" to 
the States-General June 16, 1657. This Description was republished as chap. 1 
of his magnum opus, the Horologium oscillatorium, sive de motu pendulorum 
ad horologia adaptato, dedicated to Louis XIV., March 25, 1673. In chap. 4 of 
this work he determined the centre of oscillation of a pendulum, and conse- 
quently the length of the simple isochronous pendulum. His works were 
published in two vols. 4to, Opera varia, Leyden, 1724, and two supplementary 
vols. 4to, Opera reliqua, Amsterdam, 1728. — Tr. 

4 Gabriel Mouton, 1618-1694, a French mathematician and astronomer, 
principally known by his Observationes diametrorum solis et lunse apparen- 
tium, Lyons, 1670. His principal title to honorable mention in the history 
of science is the invention of the method of differences for the calculation of 
tables of every kind, afterwards reduced to a system by Sir Isaac Newton, 
1642-1727, and known by us as our method of interpolation. — Tr. 

s Erdmann and Jacques read: " pret.pmdu montrer," i.e. claimed to demon- 
strate.— Tr. 

6 Erdmann and Jacques read : " 864,000th," evidently an error. — Tr. 



ch. xin] ON HUMAN UNDERSTANDING 151 

I have seen in manuscript. But there is, however, this imper- 
fection in this measure of pendulums, which must be limited 
to certain countries, for pendulums to beat in the same time 
need to be shorter at the etpiator. And it is furthermore 
necessary to assume the constancy of the really fundamental 
measure, viz. : the length of a day or of a revolution of the 
globe of the earth around its axis, and also of the cause of 
gravitation, not to speak of other circumstances.] 

§ 5. Ph. Observing how extremities are terminated either 
by straight lines which form distinct angles, or by curved lines 
in which no angle can be perceived, we form the idea of figure. 

Th. [A superficial figure is terminated by a line or by lines : 
but the figure of a body can be limited without determined 
lines, as for example that of a sphere. A single straight line 
or plane surface cannot enclose any space or make any figure. 
But a single line can enclose a superficial figure, for example 
the circle, the oval, as also a single curved surface can enclose 
a solid figure, like the sphere and the spheroid. Yet, not only 
several straight lines or plane surfaces, but also several curved 
lines or several curved surfaces, can concur together and form 
even angles between themselves, when the one is not the tan- 
gent of the other. It is not easy to give the definition of figure 
in general according to the usage of geometers. To say that it 
is a limited extension would be too general, for a straight line, 
for example, although terminated by the two ends, is not a 
figure and even two straight lines cannot make one. To say 
that it is an extension limited by an extension is not general 
enough, for the entire spherical surface is a figure and yet it is 
not limited by any extension. It may be said, however, that 
figure is a limited extension, in which there are an infinite num- 
ber of paths from one point to another. This definition com- 
prises limited surfaces without terminating lines which the 
preceding definition did not comprise, and excludes the lines, 
because from one point to another in a line there is only one 
path or a determined number of paths. But it will be still 
better to say that figure is limited extension, which may admit 
an extended section, or better which has breadth, a term which 
hitherto had not been further defined.] 

§ 6. Ph. At the least all figures are only simple modes of 



152 LEIBNITZ'S CRITIQUE OF LOCKE [be. ii 

Th. [According to your view, the simple modes repeat the 
same idea, but in figures there is not always the repetition of 
the same mode. Curves differ much from straight lines and 
between themselves. So I do not know how the definition of 
the simple mode will be in place here.] 

§ 7. Ph. [We need not take our definitions too strictly. 
But let us pass from figure to place.~] When we find all the 
pieces upon the same squares of the chess-board where we left 
them, we say that they are all in the same place, although per- 
haps the chess-board has been moved. We say also that the 
chess-board is in the same place, if it remains in the same part 
of the cabin of the vessel, although the vessel has sailed. The 
vessel is also said to be in the same place supposing it 
keeps the same distance with reference to the parts of the 
neighboring countries, although the earth has perhaps turned 
round. 

Th. [Place is either particular when considered with regard 
to certain bodies, or universal when it relates to all, and with 
reference to which all the changes possible in relation to any 
body are taken into account. And if there were nothing fixed 
in the universe, the place of each thing could still be deter- 
mined by reasoning, 1 if there were means of making a record of 
all the changes, or if the memory of a creature could suffice for 
them, as they say, the Arabs play chess by memory and on 
horseback. What we cannot understand, however, is neverthe- 
less determined in the truth of things.] 

§ 15. Ph. If any man asks me what space is, I am ready to 
tell him when he tells me what extension is. 

Th. [I wish I could speak of the nature of fever or any other 
malady with the same certainty with which I believe the nature 
of space is expounded. Extension is the abstract of the ex- 
tended. Now the extended is a continuum whose parts are 
coexistent, or exist at the same time.] 

§ 17. Ph. If any one asks whether space without body is 

1 Schaarschmidt says that the statements here made by Leibnitz have since 
found their confirmation and accomplishment through Gauss' Theoria motus 
corporum coelestium. The work was published at Hamburg, in 1809, and 
"gave a powerful impulse to the true methods of astronomical observation." 
The author, Carl Friedrich Gauss, 1777-1855, was an eminent German mathe- 
matician. His collected works, edited by E. J. Schering, have bef^-p" 1 ^*-' " A 
by the Royal Society of liotimyeu, 7 ™i« , ~ — -<™" ia s cu ' iw»-.l&<±. J-«. 



ch. xm] ON HUMAN UNDEESTANDING 153 

substance or accident, I should reply without hesitation that I 
know nothing about it. 

Th. [I fear you may think me vain in wishing to determine 
what you, sir, admit you do not know. But if it is expedient 
to judge, (I fear) that you know more about the matter than 
you state or think you do. Some have believed that God is 
the place of things. 1 Lessius and Guericke, if I am not mis- 
taken, were of this opinion, but then place contains something 
more than what we attribute to the space which we deprive of 
all activity ; and in this way it is no more a substance than 
time, and if it has parts it cannot be God. It is a relation, an 
order, not only between existences, but also between possibili- 
ties as they may exist. But its truth and reality, like all 
eternal truths, is grounded in God.] 

Ph. [I am not far from your view, and you know the pas- 
sage of St. Paul, who says that we live and move and have 
our being in God. 2 Thus, according to different ways of con- 
sidering the matter, it may be said that space is God, and also 
that it is only an order or a relation.] 

Th. [The better statement then will be that space is an 
order, but that God is its source.] 

§ 18. Ph. [Yet to know whether space is a substance, it 
would be needful to know in what the nature of substance in 
general consists. But in this there is a difficulty. If God, 
finite spirits, and bodies participate in common in an identical 
substantial nature, would it not follow that they differ only as 
different modifications of this substance ?] 

1 This doctrine appeared very early. Schaarschmidt refers to the collection 
of poems of uncertain origin called Orphica, where (Fragt. vi.,p. 457, ed. Her- 
mann, v. 8 and 9) it is poetically expressed thus : " All that has heen and here- 
after will he, is formed together in the hosom of Zeus." Again (v. 17-20) : 
"One is the ruling Being, in whom the All moves, fire, water, earth and air, 
day and night, reason, the first principle and joyful love — all this lies in the 
great hosom of Zeus," etc. Malebranche represents a phase of the same view 
in his doctrine that we see all things in God. C'f. his Be la Recherche de la 
Ve'rite, III., ii., 6: "We abide thus in the view that God is the intelligible 
world or the place of spirits, just as the material world is the place of bodies. 
From His power they receive all their modifications, in His wisdom they find 
all their ideas, by His love they are moved in all their moral inclinations. But 
because His power and His love are nothing else than Himself, we will believe 
with St. Paul, that He is not far from any one of us, and that in Him we live 
and move and have our being." Cf. also James Martineau, Types of Ethical 
Theorxj, 2d ed., Vol. 1, p. 170 sq. New York: Macmillan & Co., 1886. — Tr. 

2 Acts 17 :28.— Tr. 



154 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

Th. [If this result follows, it would follow also, that God, 
finite spirits, and bodies, participating in common in an iden- 
tical nature of being, would differ only as different modifica- 
tions of this being.] 

§ 19. Ph. Those who first thought of regarding accidents as 
a kind of real beings, which need something in which to inhere, 
were constrained to invent the word substance to serve as a 
support to the accidents. 

Th. [Do you then think, sir, that the accidents can subsist 
apart from the substance ? or do you mean that they are not 
real beings ? You seem to multiply difficulties without reason, 
and I have remarked above that substances or concretes are 
conceived rather than accidents or abstracts.] 

Ph. The words substance and accident are in my view of 
little use in philosophy. 

Th. [I admit that I am of another opinion, and I believe 
that the consideration of substance 1 is one of the most important 
and fruitful points of philosophy.] 

§ 21. Ph. [We have now spoken of substance only by the 
way, while asking if space is a substance. But it is sufficient 
for us that it is not a body.] No one will dare to make body 
infinite like space. 

Th. [Descartes and his followers have said, nevertheless, 
that matter has no limits, in making the world indefinite, so that 
it is not possible for us to conceive of its extremities. And 
they have changed the term infinite into indefinite with some 
reason ; for there never is an infinite whole in the world, 

1 Cf. New Essays, Bk. II., chap. 23, § 2; De primes philosophise emenda- 
tions et de notione substantias, 1694, Gerhardt, Vol. 4, pp. 468^70; Erdmann, 
pp. 121-122; A. Jacques, (Euvres de Leibniz, Vol. 1, pp. 452-454 (in French) ; 
translation, Appendix, pp. ; Systeme nouveau de la nature et de la 

communication des substances, aussi bien que de V union qu'il y a entre I'dme 
et le corps, 1695, §§ 2, 3, Gerhardt, Vol. 4, pp. 477 sq. ; Erdmann, pp. 124-128; 
Jacques, Vol. 1, pp. 469 sq. ; translation, Appendix, pp. ; De ipsa 

natura, sive de vi insita actionibusque creaturum, 1698, Gerhardt, Vol. 4, pp. 
504-516 ; Erdmann, pp. 154-160 ; Jacques, Vol. 1, pp. 455^68 (in French) ; trans- 
lation, Appendix, pp. ; Considerations sur le principe de vie et sur 
les natures plastiques, 1705, Gerhardt, Vol. 6, pp. 539-546; Erdmann, pp. 
429-432 ; translation, Duncan, Philos. Works of Leibnitz, pp. 163-169 ; Prin- 
cipes de la nature et de la grace fonde's en raison, c. 1714, Gerhardt, Vol. 6, 
pp. 598-606; Erdmann, pp. 714-718; translation, Duncan, op. cit., pp. 209-217; 
La Monadologie, 17U, Gerhardt, Vol. 6, pp. 607-623 ; Erdmann, pp. 705-712 ; 
translation, Duncan, op. cit., pp. 218-232 ; also F. H. Hedge, in " The Jour. Spec. 
Philos.," Vol. 1, pp. 129-137. —Tr. 



en. xiv] ON HUMAN UNDERSTANDING 155 

although there are always some wholes greater than others to 
infinity, and the universe even cannot pass for a whole as I 
have elsewhere 1 shown. 

Ph. Those who take matter and extension as one and the 
same thing maintain that the inner sides of a hollow vacuous 
body would touch. But the space which is between two bodies 
suffices to prevent their mutual contact. 

Th. [I am of your opinion, for although I do not admit a 
vacuum, I distinguish matter from extension, and I admit that 
if there were a vacuum in a sphere, the opposite poles in the 
hollow space would not on that account touch. But I believe 
that this is a case which the divine perfection does not allow.] 

§ 23. Ph. It seems, however, that motion proves a vacuum. 
When the least part of the divided body is as large as a grain 
of mustard-seed, a void space equal to the size of a grain of 
mustard is requisite in order to make room for the parts of 
this body to move freely ; the same condition will hold good 
when the parts of the matter are one hundred million times 
smaller. 

Th. [It is true, that if the world were full of hard corpus- 
cles, which could neither yield nor divide, as the atoms are 
depicted, motion would be impossible. But in truth, there is no 
original hardness ; on the contrary, fluidity is the original 
condition, and bodies are divided as needful, since there is 
nothing to prevent it. This takes away all the force in the 
argument for a vacuum drawn from motion.] 



CHAPTER XIV 

OF DURATION" AND ITS SIMPLE MODES 

§ 10. Ph. To extension corresponds duration. And a part 
of duration in which we remark no successions of ideas we 
call an instant. 

Th. This definition of an instant ought (I believe) to mean 
the popular notion, like that which the common people have 

1 Cf. ante, pp. 16, 17; also New Essays, Bk. II., chap. 17, § 1. The proof that 
the universe is not, strictly speaking, a whole, is given in the letter to Des 
Bosses, March 11, 1706, Gerhardt, Vol.2, p.304sg.,Erdmann, pp. 435-436. — Tr. 



156 LEIBNITZ'S CRITIQUE OF LOCKE [bk. 11 

of a point. For strictly the point and the instant are not 
parts of time or space, neither have they parts. They are 
extremities only. 

§ 16. Ph. It is not motion, but a constant succession of 
ideas which gives us the idea of duration. 

Th. [A succession of perceptions awakes in us the idea of 
duration, but it does not make it. Our perceptions never have 
a succession sufficiently constant and regular to correspond to 
that of time, which is a continuum uniform and simple, like a 
straight line. Changing perceptions furnish us the occasion 
for thinking of time, and we measure it by uniform changes. 
But were there nothing uniform in nature, time could not be 
determined, as space likewise could not be determined if there 
were no fixed or immovable body. So that knowing the rules 
of different motions, we can always refer them to the uniform 
intelligible motions, and see beforehand by this means what 
will happen through the different motions taken together. 
And in this sense time is the measure of motion, i.e. uniform 
motion is the measure of non-uniform motion.] 

§ 21. Ph. No two parts of duration can certainly be known 
to be equal; [and you must admit that observations can attain 
only approximate equality.] After exact research the dis- 
covery has been made that there is really an inequality in the 
diurnal revolutions of the sun, and we do not know but that 
the annual revolutions are unequal also. 

Th. [The pendulum has made us realize and see the in- 
equality of the days from one noon to another : Solem dicere 
falsum auclet. It is true that men knew this already, and that 
this inequality has its rules. As for the annual revolution, 
which makes good the inequalities of solar days, it may change 
in the course of time. The revolution of the earth about its 
axis which is commonly attributed to the primum mobile, 1 is our 
best measure up to the present time, and clocks and watches 
serve to divide it for us. Furthermore this same daily revolu- 

1 In Aristotle's philosophy, to irpanov klvovv, i.e. God, who, himself unmoved, 
is the necessary first and unceasing source of the eternal movement of the uni- 
verse. Cf. Metaphys., A, 6-10, 1071 sq.; Phys., VIII., 6, 258^ 10; also Zeller, 
Outlines, § 56, 3, and Die Philos. d. Griech., 3d ed., 1879, Vol. 4, p. 358; 
Wallace, Outlines of the Philos. of Aristotle, 3d ed., § 39; Hegel, Gesch. d. 
Philos., 2d ed., Vol. 2, p. 289 sq.; Benn, The Greek Philosophers, Vol. 1, pp. 
348-350. — Tr, 



ch. xiv] ON HUMAN UNDERSTANDING 157 

tion of the earth may also change in the course of time : and 
if any pyramid could endure long enough, or if we should build 
new ones we could perceive it by observing there the length of 
pendulums a known number of whose beats occurs now during 
this revolution ; we could also know in some way the change 
by comparing this revolution with others, as with those of 
Jupiter's satellites, for it is not apparent that, if there is any 
change in one or the other, it will always be proportional. 

Ph. Our measure of time would be more exact if we could 
preserve a past day in order to compare it with the days to 
come, as we preserve the measures of space. 

Th. [But instead of that we are reduced to preserving and 
watching bodies which move in nearly equal times. Also we 
cannot say that a measure of space, as for example, an ell 
which is preserved in wood or metal remains perfectly the 
same.] 

§ 22. Ph. Now since all men manifestly measure time by 
the motion of the heavenly bodies, it is very strange that one 
is not permitted to define time as the measure of motion. 

Th. [I just stated (§ 16) how that should be understood. It 
is true that Aristotle says 1 that time is the number and not the 
measure of motion. And in fact, it may be said that duration 
is known by the number of periodic equal motions of which 
one begins when another ends, for example, by so many revolu- 
tions of the earth or the stars.] 

§ 24. Ph. Nevertheless to anticipate these revolutions and 
say that Abraham was born in the year 2712 of the Julian era, 
is to speak as unintelligibly, as if you counted from the begin- 
ning of the world, although you suppose that the Julian era 
commenced several hundred years before there were any days, 
nights, or years marked by any revolution of the sun. 

Tli. [This vacuum which may be conceived in time, indicates, 
like that of space, that time and space extend to the possible as 
well as to the actual. Besides, of all the chronological methods, 
that of reckoning the years since the beginning of the world is 
the least convenient, although this would be, without touching 
upon other reasons, only because of the great difference exist- 
ing between the Septuagint and the Hebrew text.] 

1 Phys., IV., 11, 219b 1, 219b 8; e f. Wallace, Outlines of the Philos. of Aris- 
totle, 3d ed., § 44. Wallace quotes the Greek of the first passage here referred 
to. — Tr. 



158 LEIBNITZ'S CKITIQUE OF LOCKE [bk. ii 

§ 26. Ph. One may conceive the beginning of motion, al- 
though he may not comprehend that of duration taken in all 
its extension. One may give limits to the body, but cannot do 
it with regard to space. 

Th. [It is as I just said that time and space indicate the 
possibilities beyond the supposition of existences. Time and 
space are of the nature of eternal truths which consider equally 
the possible and the actual.] 

§ 27. Ph. In fact the ideas of time and eternity come from 
the same source, for we can in our thought add certain lengths 
of duration to one another as often as we please. 

Th. [But in order to draw from them the notion of eternity, 
it is necessary to think besides that the same reason always 
exists for going farther. It is this rational consideration which 
achieves the notion of the infinite or the indefinite in possible 
progress. Thus the senses alone cannot suffice to cause the 
formation of these notions. And ultimately it may be said 
that the idea of the absolute 1 is anterior in the nature of things 
to that of the limits which are added, but we notice the former 
only as we commence with what is limited and strikes our 
senses.] 

CHAPTEE XV 

OF DURATION AND EXPANSION CONSIDERED TOGETHER 

§ 4. Ph. One admits more easily an infinite duration of 
time than an infinite expansion of space, because we conceive 
infinite duration in God, and attribute extension only to matter 
which is finite, and call the space beyond the universe imaginary. 
But (§ 2) Solomon seems to have other thoughts when, speak- 
ing of God, he says : the heaven and the heaven of heavens can- 
not contain Thee; 2 and for myself I believe that he magnifies 
too highly the capacity of his own understanding who imag- 
ines he can extend his thoughts farther than the place where 
God exists. 

1 The idea of the absolute belongs to our reason as such, cf. JVeiv Essays, 
Bk. II., chap. 17, § 3, Th., § 16, Th., though we first become aware of it through 
our consciousness of the particular ideas of the reason as limitations of the 
idea of the absolute. — Tr. 

2 1 Kings 8 : 27; 2 Chron. 6 : 18. — Tr. 



en. xv J ON HUMAN UNDERSTANDING 159 

Th. If God were extended, he would have parts. But dura- 
tion grants these only to his works. However in relation to 
space immensity must be attributed to him, which gives also 
parts and order to the immediate works of God. He is the 
source of possibilities as of actualities, of the one by his 
essence, of the other by his will. Thus space like time has 
its reality only from him, and he can fill the void when it 
seems to him good. Thus it is that in this respect he is 
everywhere. 1 ] 

§ 11. Ph. We do not know what relations spirits have with 
space, nor how they participate therein. But we know that 
they participate in duration. 

Th. [All finite spirits are always united to some organic 
body, and they represent to themselves other bodies by means 
of relations to their own. Thus their relation to space is as 
evident as that of bodies. For the rest, before leaving this 
subject, I would add a comparison between time and space to 
those which you have given ; viz. : — if there were a vacuum 
in space (as, for instance, if a sphere were hollow within), you 
could determine its size ; but if there were a vacuum in time, 
i.e. a duration without changes, it would be impossible to 
determine its length. Whence it comes that you may refute 
the one who would maintain that two bodies, between which 
there is a vacuum, touch ; for geometry defends the proposition 
that two opposite poles of a hollow sphere would not touch : 
but you cannot refute the one who would maintain that two 
worlds, the one of which succeeds the other, touch as to dura- 
tion, so that the one necessarily begins when the other ends, 
without the possibility of an interval. You could not refute 
it, I say, because this interval is indeterminable. If space 
were only a line, and if body were immovable, it would no 
longer be possible to determine the length of the vacuum 
between two bodies. 

1 God, according to Leibnitz, is actus purus, a pure spirit, without body and 
without extension. All other beings require bodies. His omnipresence is 
dynamic. Cf. New Essays, Bk. II., chap. 1, § 12, Th., ante, p. 113; Letter to 
Des Bosses, Oct. 16, 1706, Gerhardt, Vol. 2, p. 325, Erdmann, p. 440, b. — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE [bjc. jb 



CHAPTER XVI 

OF NUMBER 

§ 4. Ph. In numbers ideas are both more precise and more 
accurately to be distinguished the one from the other than in 
extension, where you cannot observe or measure each equality 
and each excess of size as easily as in numbers, because in 
space we cannot by thought attain a certain definite smallness 
beyond which we cannot go, like the unit in number. 

Th. [That should be understood of the integer. For other- 
wise number in its extent, comprising the fraction, the surd, the 
transcendent, and all that may be assumed between two inte- 
gers, is proportional to the line, and there is there as little of 
a minimum as in the continuum. Thus the definition of num- 
ber as a multitude of units is in place only among the integers. 
The precise distinction of ideas in extension does not consist 
in size : for to distinguish size clearly one must have recourse 
to integers, or to other (measures) known by means of inte- 
gers ; thus from continuous quantity it is necessary to recur to 
discrete quantity, in order to have a distinct knowledge of size. 
Thus the modifications of extension, when not joined to num- 
bers, cannot be distinguished by figure, taking this term so 
generally that it means everything which makes two exten- 
sions dissimilar the one to the other.] 

§ 5. Ph. By repeating the idea of a unit and joining it to 
another unit, we make a collective idea, which we call two. 
And whoever can do that and advance always by adding one 
more to the last collective idea to which he gives a particular 
name, can count so long as he has a set of names and sufficient 
memory to retain them. 

TJi. [By this means alone one cannot advance very far. 
For memory would be too heavily loaded if it must retain an 
entirely new name for each addition of a new unit. That is 
why a certain order and a certain repetition of these names is 
necessary by recommencing in accordance with a certain pro- 
gression.] 

Ph. The different modes of numbers are capable of no other 



en. xvn] ON HUMAN UNDERSTANDING 161 

difference than that of more or less ; [this is why there are 
simple modes like those of extension.] 

Th. [That may be said of time and of the straight line, but 
not of figures, and still less of numbers, which are not only 
different in size but further unlike. An even number may be 
divided into two equal numbers, but not an uneven. Three 
and six are triangular numbers, four and nine are squares, 
eight is a cube, etc. And this principle has place in numbers 
still more than in figures, for two unequal figures may be per- 
fectly similar to each other, but never two numbers. But I 
am not astonished that you are often deceived thereupon, be- 
cause one does not commonly have a distinct idea of what is 
similar or dissimilar. You see then, sir, that your idea or 
your application of simple or mixed modes is greatly in need of 
correction.] 

§ 6. Ph. [You were right in remarking that it is well to 
give numbers their own names to be retained.] Thus I believe 
that it would be convenient in computation to say a billion for 
brevity's sake instead of a million of millions, and instead of a 
million of millions of millions, or a million of billions, to say 
a trillion, and thus in order to nonillions, for there is little 
need of going farther in the use of numbers. 

Th. These denominations are good enough. Let £=10. 
That posited, a million will be x e , a billion x 12 , a trillion a; 18 , 
etc., and a nonillion x 5i . 



CHAPTER XVII 

OF INFINITY 

§ 1. Ph. One of the most important notions is that of 
the finite and the infinite, which are regarded as modes of 
quantity. 

Th. [Properly speaking, it is true that there is an infinite 
number of things, i.e. that there are always more of them than 
can be assigned. But there is no infinite number, neither line 
nor other infinite quantity, if these are understood as veritable 
wholes, as it is easy to prove. The schools have meant or have 
been obliged to say that, in admitting a syncategorematic in- 

M 



162 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

finite, 1 as they call it, and not a categorematic infinite. The 
true infinite exists, strictly speaking, only in the absolute, which 
is anterior to all composition, and is not formed by the 
additions of parts. 2 ] 

Ph. When we apply our idea of the infinite to the first 
Being, we do it primarily in respect to his duration and ubi- 
quity, and, more figuratively, to his power, his wisdom, his 
goodness, and his other attributes. 

Th. [Not more figuratively, but less immediately, because 
the other attributes make their importance known through 
relation to those into which enters the consideration of 
parts.] 

§ 2. Ph. I thought it was established that the mind regards 
the finite and the infinite as modifications of extension 3 and 
duration. 

Th. [I do not find that it has been established that the con- 
sideration of the finite and the infinite takes place wherever . 
there is bulk and magnitude. And the true infinite is not a 
modification, it is the absolute ; on the contrary, when it is 
modified, it is limited and forms a finite.] 

§ 3. Ph. We have believed that since the power of the 
mind to expand without limit its idea of space by new addi- 
tions is always the same, it is thence that the idea of an infi- 
nite space is derived. 

Th. [It is well to add that this is because the same ratio is 
seen always to hold good. Let us take a straight line and 
prolong it until it is double the length of the first. Now it 
is clear that the second line, being perfectly similar to the 
first, may be itself doubled in order to have a third, which is 
still similar to the preceding ; and the same ratio holding 
good always, it is never possible to stop the process ; thus 
the line may be prolonged to infinity, so that the consideration 
of the infinite arises from that of similarity or from the same 
ratio, and its origin is the same with that of universal and 
necessary truths. This shows us how what gives completion 

1 An incompletely defined infinite, capable of or needing still further defini- 
tion, but infinite only so far as it cannot really be defined, the indefinite- 
infinite (infinitum-ind-efinitum) . — Tr. 

2 Cf. ante, pp. 1(3, 17 ; also New Essays, Bk. II., chap. 13, § 21. — Tr. 

3 Locke has: "expansion," Philos. Works, Vol. 1, p. 331 (Bohn's ed.). — 
Tr. 



ch. xvii] ON HUMAN UNDERSTANDING 163 

to the conception of this idea is found in ourselves, and can- 
not come from the experience of our senses, just as necessary 
truths cannot be proved by induction nor by the senses. The 
idea of the absolute is in us internally, like that of being ; these 
absolutes are nothing else than the attributes of God, and it 
may be said that they are not less the source of ideas, because 
God is himself the principle of beings. The idea of the abso- 
lute in relation to space, is only that of the immensity of 
God, and so of the others. But you deceive yourself in wish- 
ing to imagine an absolute space which is an infinite whole 
composed of parts ; there is none such, it is a notion which 
implies a contradiction, and these infinite wholes, and their 
opposed infinitesimals, are used only in the calculations of 
geometers, just like the imaginary roots of algebra.] 

§ 6. Ph. [We conceive furthermore a magnitude without 
understanding thereby parts outside of parts.] If to the most 
perfect idea I have of the whitest whiteness, I add another of 
an equal or less brilliant whiteness (for I cannot add the idea 
of a whiter than I have, which I suppose the whitest that I 
actually conceive), it neither increases nor extends my idea in 
any way ; therefore the different ideas of whiteness are called 
degrees.'] 

Th. [I do not fully understand the force of this reasoning, 
for nothing prevents me from receiving the perception of a 
whiter whiteness than what is actually conceived. The true 
reason why we are inclined to believe that whiteness cannot be 
infinitely increased is because it is not an original quality ; 
the senses give us only a confused knowledge of it ; and when 
we have a distinct knowledge of it, we shall see that it arises 
from the structure, and is limited by that of the organ of 
vision. But as regards original or distinctly knowable quali- 
ties, we see that there are sometimes means of going to 
infinity, not only in the case of extension or, if you prefer, 
diffusion or what the scholastic philosophy calls partes extra 
partes, as in time and place, but also in the case of intention or 
degrees, for example, as regards velocity.] 

§ 8. Ph. We have no idea of infinite space, and nothing is 
plainer than the absurdity of an actual idea of an infinite 
number. 

Th. [I am of the same opinion. But this is not because we 



164 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

cannot have the idea of the infinite, but because the infinite 
cannot be a true whole.] 

§ 16. Ph. For the same reason we have then no positive 
idea of an infinite duration or of eternity, any more than of 
immensity. 

Th. [I believe we have a positive idea of both, and this 
idea is a true one, provided it is not conceived as an infinite 
whole, but as an absolute or attribute without limits which 
exists in reference to eternity, in the necessity of the existence 
of God, without depending upon parts and without the notions 
being formed by an addition of time. We see furthermore in 
that way, as I have said already, that the origin of the notion 
of the infinite comes from the same source as that of necessary 
truths.] 

CHAPTER XVIII 

OF OTHER SIMPLE MODES 

Ph. There are besides many simple modes formed from 
simple ideas. Such are (§2) modes of motion, as sliding, 
rolling; those of sound (§ 3) which are modified by notes and 
airs, as colors by degrees, not to speak of tastes and smells 
(§6). These always 1 have neither measures nor distinct 
names any more than in the case of the complex modes (§ 7), 
because use regulates them, and we will speak of them more 
fully when we come to words. 

Th. [The majority of modes are not sufficiently simple and 
can be reckoned with the complex, for example, to explain what 
sliding and rolling is besides motion, you must consider sur- 
face-resistance.] 

CHAPTER XIX 

OF THE MODES OF THINKING 

§ 1. Ph. [Let us pass from the modes which come from the 
senses to those given us by reflection.] Sensation is, so to 
speak, the actual entrance of ideas into the understanding by 

i Locke: "ordinarily," Philos. Works, Vol. 1, p. 346 (Bonn's ed.). — Tr. 



ch. xix] ON HUMAN UNDERSTANDING 165 

means of the senses. When the same idea comes again into 
the mind, without the action upon our senses, of the external 
object which at first caused it to spring up, the act of the 
mind is called remembrance ; if the mind tries to recall it, and 
only after considerable effort finds and brings it to view, it is 
recollection (recueillement). 1 If the mind looks upon it atten- 
tively for a long time it is contemplation; when the idea floats 
about in the mind without any attention on the part of the 
understanding, it is called reverie. When the mind reflects 
upon ideas, which present themselves, and when it, so to speak, 
registers them in its memory, it is attention; and when the 
mind fixes itself upon an idea with much application, considers 
it on all sides, and will not be turned aside notwithstanding 
other ideas which come in the way, we call it study or intense- 
ness of thought. Sleep accompanied by no dream is a cessa- 
tion of all these things ; and dreaming is having these ideas in 
the mind while the outer senses are closed, so that they do 
not receive the impressions of external objects with their 
usual quickness. It is, I say, having ideas without any sug- 
gestion from any external objects or known occasion, and 
apart from any choice or determination in any way of the 
understanding. As for that which we call ecstasy, I leave 
others to judge whether it is not dreaming with the eyes open. 
Th. [It is well to clear up these notions and I will try to 
aid in the work. I will say then that it is sensation when an 
external object is perceived; that remembrance consists in the 
repetition without the reappearance of the object ; but when 
we know we have had it, it is memory. Recollection (recueille- 
ment) is commonly understood in a sense different from yours, 
viz. : as a state in which we disengage ourselves from things 
in order to apply ourselves to some meditation. But since 
there is no word known to me corresponding to your notion, 
sir, one may apply to it that which you employ. We give 
attention to objects which we distinguish and prefer to others. 
Attention continuing in the mind, whether the external object 
continues or not, and even whether it is found there or not, is 

1 Cf. below, where the French "recueillement," here employed as a trans- 
lation of the English "recollection," is shown to have a different meaning 
and use from that of the English word. As " recueillement " is, however, used 
as an equivalent for the English word, I have translated it in the second para- 
graph accordingly. — Tr. 



166 LEIBNITZ'S CKITIQUE OF LOCKE [bk. 11 

consideration ; which, tending to knowledge without reference 
to action, will be contemplation. Attention, whose aim is to 
learn (i.e. the attainment of knowledge for the sake of keep- 
ing it), is study. To consider in order to form a plan is to 
meditate; but reverie appears to be nothing else than following 
certain thoughts for the pleasure one takes therein, with no 
other end ; this is why reverie may lead to madness ; we forget 
ourselves, we forget the die cur hie, we approach dreams and 
chimeras, we build castles in Spain. We can distinguish 
dreams from sensations only because they are not united with 
them, they are like a world apart. Sleep is a cessation of sen- 
sations, and in this way ecstasy is a very deep sleep from which 
one finds difficulty in being awakened, a condition which arises 
from some internal passing cause, which is added in order to 
exclude this profound sleep, arising from some narcotic or 
from some continuous injury to the functions, as in lethargy. 
Ecstasy is sometimes accompanied with visions; but there is 
vision without ecstasy, and vision seems to be nothing but a 
dream which passes for a sensation just as if it acquainted us 
with the truth of objects. And when visions are divine, there is 
actually truth in them, which may be known for instance when 
they contain particular prophecies which the outcome justifies.] 

§ 4. Pit. From the different degrees of intensity 1 or relaxa- 
tion of the mind, it follows that thought is the act and not the 
essence of the soul. 

Tli. [Doubtless thought is an act and cannot be the essence: 
but it is an essential act, and alb substances are of this charac- 
ter. I have shown above that we always have an infinite 
number of little perceptions, without being conscious of them. 
We are never without perceptions, but we are necessarily often 
without apperceptions, viz. : when there are no distinct per- 
ceptions. It is from not having considered this important 
point that a relaxed philosophy, as little noble as solid, has 
prevailed with so many excellent minds, and that we have 
hitherto almost ignored that which is most beautiful in the 
soul. This is also the reason why so much probability has 
been found in that error, which teaches that souls are by 
nature perishable.] 

1 Locke has: "intention and remission," Philos. Works (Bonn's ed.), Vol. 
1, p. 349. — Tr. 



ch. xx] ON HUMAN UNDERSTANDING 167 

CHAPTER XX 

OF MODES OF PLEASURE AND PAIN 

§ 1. Ph. As the sensations of the body, like the thoughts 
of the mind, are either indifferent or followed by pleasure or 
pain, the ideas of them cannot be described any more than all 
other simple ideas, nor can the words which serve to designate 
them be defined. 

Th. [I believe that there are no perceptions which are 
wholly indifferent to us, but it is enough that their effect be 
not notable in order that they may be thus spoken of, for 
pleasure and pain appear to consist in a notable aid or impedi- 
ment. I admit that this definition is not at all nominal and 
that one may give none at all.] 

§ 2. Ph. The good is that which is fitted to produce and 
increase pleasure in us, or to diminish and cut short some 
pain. Evil is fitted to produce or increase pain in us, or to 
diminish some pleasure. 

Th. [I am also of this opinion. The good is divided into 
the virtuous, the agreeable, and the useful, but ultimately I 
believe that it must be either agreeable itself, or serving some- 
thing else which may give us an agreeable feeling, that is to 
say, the good is agreeable or useful, and virtue itself consists 
in a pleasure of mind.] 

§§ 4, 5. Ph. From pleasure and pain come the passions. 
We have love for that which can produce pleasure, and the 
thought of sadness or of pain that a present or absent cause 
can produce is hatred. But hatred or love which relates to 
beings capable of happiness or misery is often an uneasiness or 
delight which we feel to be produced in us by the considera- 
tion of their existence or of the happiness which they enjoy. 

Th. [I also gave nearly this definition of love when I 
explained the principles of justice, in the preface to my 
"Codex juris gentium diplomaticus," 1 viz. r'that to love is to 

1 The Codex juris gentium diplomaticus, 1693, a collection of public acts 
and treatises, etc. An excerpt from the Preface of this work, entitled Be no- 
tionibus juris et justitise, is given by Erdmann, pp. 118-120; translation, Dun- 
can, Philos. Works of Leibnitz, note 48, pp. 379-382.— Tk. 



168 LEIBNITZ'S CEITIQUE OE LOCKE [bk. ii 

be inclined to take pleasure in the complete perfection or hap- 
piness of the object loved. And for that reason one neither 
considers nor asks for any other pleasure proper than that 
indeed which is found in the good or pleasure of the one who 
is loved ; ( but in this sense we do not, properly speaking, love 
what is incapable of pleasure or happiness, and we enjoy things 
of this nature without loving them for that reason, unless by 
a prosopopoeia, and as if we imagined that they themselves 
enjoy their perfection. It is not, then, properly love when 
one says that he loves a beautiful picture for the pleasure 
which he takes in feeling its perfections. But it is allowable 
to extend the sense of terms, and their usage varies. Philoso- 
phers and theologians even distinguish two kinds of love, viz. : 
the love which they call the love of complacency, which is 
nothing but the desire or feeling which we have for the one 
who gives us pleasure, without concerning ourselves whether 
he receives it ; and the love of benevolence, which is the feeling 
that one has for the one who, by his pleasure or happiness, 
gives us some. The first makes us have in view our pleasure 
and the second that of another, but as making or rather consti- 
tuting ours, for if it did not reflect upon us in some way we 
could not concern ourselves with it since it is impossible, 
although they affirm it, to be separated from the good proper. 
And see how it is needful to understand disinterested or non- 
mercenary love, in order to reach a favorable conception of 
nobility and not to fall meanwhile into the chimerical one.] 

§ 6. Ph. The uneasiness (French inquietude) which a man 
feels in himself at the absence of anything which if present 
would give him pleasure is called desire. Uneasiness is the prin- 
cipal, not to say the only stimulus which excites human industry 
and action for whatever good is proposed to man ; if the absence 
of this good is followed by no displeasure or pain, and he who is 
deprived of it can be content and at his ease without its pos- 
session, he does not think of desiring, and less still of making 
any efforts to enjoy it. He feels for this kind of good only a 
bare velleity, 1 the term used to signify the lowest kind of desire, 

1 Schaarschmidt translates the French " velleite " hy the German " Willens- 
neigung," i.e. inclination of will. The term is borrowed from the Scholastic 
"velleitas," and is here equivalent to imperfect volition (imperfecta volitio) 
or that condition of the soul in which the will, though not in a state of indiffer- 



en. xx] ON HUMAN UNDERSTANDING 169 

which approaches nearest to that state in which the soul finds 
itself with regard to anything which is wholly indifferent to 
it, when the displeasure which the absence of anything causes 
is so inconsiderable that it is carried only to feeble longings 
without being compelled to avail itself of the means of obtain- 
ing it. Desire is moreover extinguished or abated by the 
opinion that the wished for good cannot be obtained in propor- 
tion as the soul's uneasiness is cured or allayed by that con- 
sideration. [For the rest, I have found what I stated to you 
about uneasiness in this celebrated English author, whose 
views I often relate to you. I was a little in difficulty as to 
the definition of the English word uneasiness. But the French 
translator 1 whose skill in the fulfilment of this task cannot 
be called in question, remarks at the foot of the page (chap. 
20, § 6,) that by this word the English author understands 
the state of a man not at his ease, the lack of ease and of tran- 
quillity of soul, which in this regard is purely passive, and that 
it must be translated by the (French) word inquietude, which 
does not express exactly the same idea, but approaches it very 
nearly. This caution (he adds) is above all needful with 
regard to the following chapter, "Of Power," in which the 
author reasons much upon this kind of uneasiness ; for if you 
should not attach to this word the idea which has just been 
indicated, it would be impossible exactly to understand the 
matters treated of in this chapter and which are the most 
important and delicate in the entire work.] 

Th. [The translator is right and the reading of his excellent 
author shows me that this consideration of uneasiness is a capi- 
tal point, in which this author has particularly shown his pene- 
trating and profound mind. For this reason I gave it some 
attention, and after having well considered the matter, it al- 
most appears to me that the (French) word inquietude (restless- 
ness) , if it does not express quite the meaning of the author, 
nevertheless sufficiently agrees with the nature of the thing ; 
and that the (English) word uneasiness, if it indicated a dis- 
pleasure, fretfulness (chagrin), inconvenience, in a word some 
effective pain, would not suit his meaning. For I should pre- 

ence, has not as yet sufficient force to pass over into action (volitio). Cf. New 
Essays, Bk. II., chap. 21, § 5 sq., also § 30, Th. — Tr. 
1 M. Pierre Coste. — Tr. 



170 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

fer to say that in the desire in itself there is rather a disposi- 
tion and preparation for pain than pain itself. It is true that 
this perception sometimes differs from that which is in pain 
only more or less, but it is the degree which is the essence of 
pain, for it is a notable perception. The same is also seen in 
the difference between appetite and hunger, for when the 
stomach's irritation becomes too strong it is uncomfortable, so 
that we must also apply here our doctrine of perceptions too 
small to be perceived, for if that which goes on in us when we 
have appetite and desire, were great enough, it would cause us 
pain. Hence the infinitely wise author of our being arranged 
it for our good, when he so arranged it that we should often 
be in ignorance and among confused perceptions, in order to 
act more promptly by instinct, and in order not to be disturbed 
by too distinct sensations of a multitude of objects, which do 
not recur immediately and the nature of which could not go on 
to obtain their ends. How many insects we swallow without 
noticing them, how many persons we see who, having a too 
penetrating odor, are annoying, and how many disgusting ob- 
jects we should see if our vision were penetrating enough. It 
is also for the sake of this skill that nature has given us the 
stimuli of desire, like the rudiments or elements of pain, or so 
to speak, of semi-pains, or (if you wish to speak extravagantly 
in order to express yourself more forcibly) the little impercep- 
tible pains, in order that we might enjoy the advantage of evil 
without its inconvenience ; for otherwise if this perception 
were too distinct, we would always be miserable while await- 
ing the good, while this continual victory over these semi- 
pains which are felt in pursuing our desire and satisfying in 
some way this appetite, or this longing, gives us a quantity of 
semi-pleasures, whose continuity and mass (as in the continuity 
of the impulse of a heavy body which falls and acquires im- 
petuosity) becomes at last a complete and genuine pleasure. 
And finally, without these semi-pains there would be no pleas- 
ure at all, nor any means of perceiving that something aids 
and relieves us while there are some obstacles which prevent 
us from putting ourselves at ease. It is furthermore in this 
that we recognize the affinity of pleasure and pain which Soc- 
rates in Plato's " Phseclo," l noticed when his feet itched. This 
1 Phxdo, 60 b.— Tr. 



ch. xx] ON HUMAN UNDEESTANDING 171 

consideration of little aids or little releases and imperceptible 
deliverances from the fixed tendency, whose resnlt at last is a 
notable pleasure, serves also to give a more distinct knowl- 
edge of the confused idea which we have, and ought to have, of 
pleasure and of pain; just as the sensation of heat and of light 
results from a quantity of little motions which express those 
of objects, as I said above (chap. 9, § 13) and differ from them 
only in appearance and because we ourselves are not conscious 
of this analysis : while many to-day believe that our ideas of 
sense-qualities differ toto genere from notions and from all that 
goes on in objects, and are something primitive and inexpli- 
cable, and indeed arbitrary, as if God made the soul sensible of 
whatever seems good to him, instead of what goes on in the 
body, a view which is far removed from the true analysis of our 
ideas. But to return to uneasiness, that is to say to the little 
imperceptible solicitations which keep us always in suspense ; 
these are confused determinations, so that often we do not 
know what we lack, while in the case of the inclinations and 
passions we at least know what we ask for, although confused 
perceptions enter also into their methods of acting, and the 
passions themselves also cause this uneasiness or longing. 
These impulses are like so many little springs which try to 
release themselves, and which make our machine go. And I 
have already remarked above that it is in this way that we are 
never indifferent, when we most appear to be so, for example, 
in turning to the right rather than to the left at the end of a 
path. For the side we take arises from these insensible deter- 
minations, mixed with the actions of objects and the interior of 
the body, which makes us find ourselves more at ease in the one 
or the other manner of bestirring ourselves. The pendulum of 
a clock is called JJnruhe in German, i.e. uneasiness. We may 
say that the same condition exists in our body which can 
never be perfectly at ease ; because if it might be so, a new 
impression of objects, a slight change in the organs, in the ves- 
sels and in the viscera would at once alter the balance and 
cause them to make some slight effort to put themselves again 
in the best state possible : this produces a perpetual strife, 
which causes, so to speak, the uneasiness of our clock, so that 
this appellation is quite to my taste.] 

§ 6. Ph. Joy is a pleasure felt by the soul when it consid- 



172 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

ers the possession of a present or future good as assured, and 
we are in possession of a good when it is so in our power that 
we can enjoy it when we wish. 

Th. [Languages lack words sufficiently suitable to distin- 
guish kindred notions. Perhaps the Latin gaudium draws 
nearer this definition of joy than Iwtitia, which is also trans- 
lated by the word joy; but then it appears to me to signify a 
state in which pleasure predominates in us, for during the pro- 
foundest sorrow and in the midst of the most poignant grief 
one may take some pleasure as in drinking or hearing music, 
but the unpleasant feeling predominates and so in the midst 
of the most acute pain the mind can be joyful, as in the case 
of the martyrs.] 

§ 8. Ph. Sorrow is an uneasiness of the soul when it 
thinks of a lost good which it might have enjoyed a longer 
time, or when it is tormented by an actually present evil. 

Th. [Not only the actual presence, but also the fear of 
coming evil may make one sad, so that I believe the definitions 
of joy and sorrow which I have just given agree the better 
with usage. As to uneasiness, there is in pain and consequently 
in sorrow something more : and there is uneasiness even in 
joy, for it makes a man awake, active, full of hope to go farther. 
Joy has been capable of causing death by excess of emotion, 
and then there was in it still more than uneasiness.] 

§ 9. Ph. Hope is the contentment of the soul which thinks of 
the enjoyment which it is destined probably to have in a thing 
suited to give it pleasure. § 10. And fear is an uneasiness 
of the soul, at the thought of a future evil that may happen. 

Th. [If uneasiness signifies trouble I admit that it always 
accompanies fear ; but taking it as this insensible spur which, 
pushes us on, it may be applied also to hope. The Stoics 
regarded the passions as thoughts ; thus hope was to them the 
thought of a future good, and fear the thought of a future 
evil. But I prefer to say that the passions are neither satis- 
factions nor displeasures, nor thoughts, but tendencies or 
rather modifications of the tendency, which come from thought 
or feeling and which are accompanied by pleasure or displeas- 
ure.] 

§ 11. Ph. Despair is the thought one has that a good 
cannot be obtained, causing sometimes pain and sometimes 
rest. 



ch. xx] ON HUMAN UNDERSTANDING 173 

Th. [Despair taken as passion is a kind of strong tendency 
which finds itself suddenly arrested, a condition which causes 
a violent struggle and much displeasure. But when despair 
is accompanied with rest and indolence it is rather a thought 
than a passion.] 

§ 12. Ph. Anger is the uneasiness or discomposure we feel 
after having received some injury, and which is accompanied 
with a present desire to avenge ourselves. 

Th. [Anger seems to be something simpler and more gen- 
eral, since animals are susceptible to it to whom no injury is 
done. There is in anger a violent effort tending to annul the 
evil. The desire for vengeance may remain when one is in 
cold blood and has hatred rather than anger.] 

§ 13. Ph. Envy is the uneasiness (displeasure) of the soul 
which arises from the consideration of a good we desire, but 
which another possesses, who in our opinion should not have 
had it in preference to ourselves. 

Th. [According to this notion envy would be always a 
praiseworthy passion and always based upon justice, at least 
in our opinion. But I know not whether men do not often bear 
envy towards recognized merit, which they would not hesitate 
to treat ill, if they had the power. They even bear envy 
towards persons regarding a good which they themselves 
would not care to have. They would be content to see them 
deprived of it, without thinking of profiting from their despoil- 
ments, and indeed without being able to hope for it. For 
some good things are like pictures painted in fresco, which can 
be destroyed, but which cannot be taken away.] 

§ 17. Ph. Most of the passions make in many persons 
impressions on the body, and cause therein various changes, 
but these changes are not always sensible ; for example, shame 
which is a felt uneasiness of the soul when it comes to consider 
that it has done something indecent or which may lessen the esti- 
mate others have of us, is not always accompanied by blushing. 

Th. [If men would study to observe more closely the ex- 
ternal movements which accompany the passions, it would be 
difficult to conceal them. As for shame, it is worthy of consid- 
eration that modest persons sometimes feel movements similar 
to those of shame, when they are witnesses only of an indecent 
action.] 



LEIBNITZ'S CRITIQUE OF LOCKE [be, 



CHAPTER XXI 

OF POWER AND FREEDOM 

§ 1. Ph. [The mind observing how one thing ceases to be, 
and how another which was not before comes to exist, and 
concluding that there will be in the future parallel cases, pro- 
duced by parallel agents, comes to consider in one thing the 
possibility that one of its simple ideas may be changed, and in 
another the possibility of producing that change, and in that 
way the mind forms the idea of power.] 

Th. [If power corresponds to the Latin potentia, it is opposed 
to act, and the passage from power to act is change. This is 
what Aristotle understands by the word motion, when he says 1 
that it is the act or perhaps the actuation of that which is in 
power. It may be said then that power in general is the possi- 
bility of change. ISTow change or the act of this possibility, 
being action in one subject and passion in another, there 
will be two powers, one passive, the other active. The active 
may be called faculty, and perhaps the passive might be called 
capacity or receptivity. It is true the active power is sometimes 
taken in a more complete sense, when besides the simple faculty 
there is a tendency ; and it is thus that I take it in my dynamical 
considerations. 2 The word force might be appropriated to it 
in particular ; and force would be either entelechy or effort ; 
for entelechy (although Aristotle takes it so generally that it 
comprises also all action and all effort) appears to me more 
appropriate to primitive acting forces, and that of effort to the 
derivative. There is even also a kind of passive power more 
particular and more endowed with reality ; namely, that which 
is in matter in which there is not only mobility, which is the 

1 Cf. Phys. III., 1, 20W0; Metaphys. K, 9, 1065 5 16. — Tr. 

2 Cf. Be primse philosophies emendatione, etc., published in the "Acta 
Eruditorum," 1694, p. 110 sq., Gerhardt, Vol. 4, pp. 468-470; Erdmann, pp. 
121-122 ; Jacques, Vol. 1, pp. 452-454, in French ; translation, Duncan, Philos. 
Works of Leibnitz, pp. 68-70; also, Beilage, May, 1702, appended by Gerhardt 
to the letter to Fabri, Gerhardt, Leibnizens Math. Schriften, Vol. 6, pp. 98 sq., 
especially p. 101 ; Specimen dynamicum, published in the " Acta Erudi- 
torum," April, 1695, Gerhardt, Leibnizens Math. Schriften, Vol. 6, pp. 234 sq 
— Tr. 



en. xxi] ON HUMAN UNDERSTANDING 175 

capacity or receptivity for motion, but also resistance, which 
includes impenetrability and inertia. Entelechies, i.e. primitive 
or substantial tendencies, when accompanied by perception, are 
souls.] 

§ 3. Ph. The idea of power expresses some kind of relation. 
But what one of our ideas of whatever kind does not include some 
relation? Our ideas of extension, of duration, of number, do 
they not all contain in themselves a secret relation of parts ? 
The same thing is noticed in a still more visible manner in 
figure and motion. Sensible qualities, what are they but the 
powers of different bodies in relation to our perception, and 
do they not depend in themselves upon bulk, figure, the con- 
texture and motion of the parts ? which puts a kind of rela- 
tion between them. Thus our idea of power may very well be 
placed in my opinion among the other simple ideas. 

Th. [At bottom the ideas which we have just enumerated 
are composite ; those of sensible qualities hold their place 
among the simple ideas only because of our ignorance, and the 
others which we know distinctly, keep their place only by an 
indulgence which it were better they should not have. It is 
almost the same with regard to the common axioms, which 
might be and which deservedly should be proved among the 
theorems, and which are allowed to pass nevertheless as 
axioms, as if they were primitive truths. This indulgence 
does more harm than we think. It is true we are not always 
in a position to do without it.] 

§ 4. Ph. If we consider the matter carefully, bodies do not 
furnish us by means of the senses with so clear and so distinct 
an idea of active power as that which we have from reflection 
upon the workings of our mind. There are, I believe, but two 
kinds of actions of which we have an idea, viz. : thinking and 
motion. Of thought, body gives us no idea, and it is only 
through reflection that we have it. Neither have we from the 
body any idea of the beginning of motion. 

Th. [These considerations are most excellent, and although 
here I take thought in a manner so general that it includes all 
perception, I do not wish to dispute the use of terms.] 

Ph. When the body is itself in motion, this motion in the 
body is an action rather than a passion ; but when a billiard- 
ball yields at the stroke of the cue, it is not an action of the 
ball, but a simple passion. 



176 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

Th. [There is something to be said upon that point, for the 
bodies did not receive motion in the impact, according to the 
laws observed therein, if they already had not motion in 
themselves. But pass we now this point.] 

Ph. The same is true when it pushes another ball which it 
finds in its way and puts in motion ; it only communicates to 
it the motion it had received, and itself loses just as much. 

Th. [I see that this erroneous view, which the Cartesians 
have brought into fashion, as if bodies lost as much motion as 
they give to others, which is to-day overthrown by experi- 
ments and by reason, and abandoned moreover by the illustri- 
ous author of " The Search after Truth," 1 who has published 
a brief treatise for the express purpose of retracting it, still 
gives scholars occasion to be mistaken in constructing trains 
of reasoning upon so ruinous a foundation.] 

Ph. The transfer of motion gives us only a very obscure 
idea of an active power of motion in the body so long as we 
see nothing else than that the body transfers motion but does 
not in any way produce it. 

Th. [I do not know whether they here maintain that motion 
passes from subject to subject, and that the same motion (idem 
numero) is transferred. I know that some, contrary to the 
view of the entire scholastic philosophy, have gone that far, 
among others the Jesuit, Father Casati. But I doubt whether 
this is your view or that of your scholarly friends, ordinarily far 
removed from such fancies. If, however, the same motion is 
not transferred, we must admit that a new motion is produced 
in the body which receives it : thus the one which gives 
would really act, although it would be passive at the same 
time while losing its force. For although it is not true that 
the body loses as much motion as it gives, it is always true 
that it loses some motion and that it loses as much force as it 
gives, as I have elsewhere explained, so that it is always nec- 
essary to admit in it force or active power. I understand 
power in the more noble sense which I have explained a little 
before, in which tendency is united with faculty. Nevertheless, 

1 Malebranche, De la Recherche de la Verite, 1674. The "brief treatise" 
referred to is entitled: Traite de la communication du movement, and may- 
be found in Vol. 3 of the German translation of Malebranche's works, Halle, 
1777-80.— Tr. 



ch xxi] ON HUMAN UNDEKSTANDING 177 

I am always agreed with you, that the clearest idea of 
active power comes to us from the mind. It is also only 
in things which are analogous to the mind, that is to say, in 
entelechies, for matter properly speaking shows only passive 
power.] 

§ 5. Ph. We find in ourselves the power to begin or not to 
begin, to continue or to end many actions of our soul and 
many motions of our body, and this simply by a thought or 
choice of our mind, which determines and commands, so to 
speak, that such a particular action be done or not done. This 
power we call Will. The actual use of this power is called 
Volition; the cessation or production of the action which fol- 
lows such a command of the soul, is called voluntary, and all 
action done without such direction of the soul is called invol- 
untary. 

Tli. [I find all that very good and just. However, to speak 
more fairly, and to go perhaps a little farther, I will say that 
volition is the effort or tendency (conatus) towards what is 
considered good and against that considered bad, so that this 
tendency results immediately from the consciousness one has 
of them. And the corollary of this definition is this cele- 
brated axiom : that will and power united, action follows, 
since from all tendency action follows when it is not hin- 
dered. Thus not only the internal voluntary actions of our 
minds follow from this conatus, but also the external, that is to 
say, the voluntary movements of our bodies, in virtue of the 
union of the soul and the body, the reason of which I have 
elsewhere given. There are besides the efforts resulting from 
the insensible perceptions, of which we are not conscious, 
which I prefer to call appetitions rather than volitions (al- 
though there are also apperceptible appetitions), for those 
actions alone are called voluntary of which we may be con- 
scious, and upon which our reflection may fall when they fol- 
low the consideration of good and evil.] 

Ph. The power of perceiving we call understanding : it in- 
cludes the perception of ideas, the perception of the signifi- 
cation of signs, and, finally, the perception of the agreement 
or disagreement existing between any of our ideas. 

Tli. [We perceive many things within and without us, 
which we do not understand, and we understand them, when 
sr 



178 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

we have distinct ideas of them, together with the power of 
reflection and of drawing from them necessary truths. Ani- 
mals therefore have no understanding, at least in this sense, 
although they have the faculty of perceiving impressions 
more remarkable and more distinct, as the boar perceives a 
person who shouts at him, and goes straight for this person, of 
whom he had had before only a cloudy perception, but con- 
fused as of all other objects which fell under his eyes, and 
whose rays struck his crystalline humor. Thus in my view 
the understanding corresponds to what among the Latins is 
called intellectus, and the exercise of this faculty is called 
intellection, which is a distinct perception united with . the fac- 
ulty of reflection, which is not in animals. Every perception 
united with this faculty is a thought, which I do not accord to 
the animals any more than understanding, so that we may say 
there is intellection when thought is distinct. For the rest, 
the perception of the signification of signs does not deserve 
to be distinguished here from the perception of the ideas 
signified.] 

§ 6. Ph. It is commonly said that the understanding and 
the will are two faculties of the soul, a term suitable enough if 
used as we ought to use all words, taking care that they cause 
no confusion to spring up in the thoughts of men, as I suspect 
has happened here in the case of the soul. And when we are told 
that the will is that superior faculty of the soul which rules 
and orders all things, that it is or is not free, that it deter- 
mines the lower faculties, that it follows the dictamen of the 
understanding ; although these expressions may be understood 
in a sense clear and distinct, I fear, however, that they have 
caused to arise in many persons the confused idea of so many 
distinct agents acting distinctly in us. 

Th. The question has exercised the scholastics a long time 
whether there is a real distinction between the soul and its 
faculties, and whether one faculty is really distinct from 
another. The Realists have said yes, and the Nominalists, 
no, and the same question has been agitated as to the reality 
of many other abstract entities, which should meet the same 
fate. But I do not think we need here decide this question 
and plunge into these difficulties, although I remember that 



ch. xxi] ON HUMAN UNDERSTANDING 179 

Episcopius * found it of such importance that he thought he 
could not maintain the freedom of man if the faculties of the 
soul were real entities. However, if they were real and dis- 
tinct entities, they can pass for real agents only in extravagant 
speech. It is not the faculties or qualities which act, but sub- 
stances by means of the faculties. 

§ 8. Ph. So long as man has the power to think or to 
refrain from thinking, to move or not to move according to 
the preference or choice of his own mind, so long he is free. 

Th. [The term freedom is very ambiguous. There is free- 
dom of right and of fact. As regards that of right a slave is 
not at all free, a subject is not wholly free, but a poor man is 
as free as a rich man. Freedom of fact consists either in the 
power to ivill as one ought, or in the power to do what one wills. 
It is of the freedom to do of which you speak, and it has its 
degrees and varieties. Generally he who has the most means 
is the freest to do what he wills : but in particular freedom is 
understood of the use of things which are ordinarily in our 
power, and above all, of the free use of our body. Thus the 
prison and the diseases which prevent us from giving to our 
body and our limbs the motion we wish and which we can 
ordinarily give them detract from our freedom : thus a prisoner 
is not at all free, and a paralytic has no free use of his limbs. 
Freedom of will is furthermore understood in two different 
senses. The first is when it is opposed to the imperfection or 
the slavery of the spirit, which is a coaction or constraint, but 
internal like that arising from the passions. The other sense 
has place when freedom is opposed to necessity. In the first 
sense the Stoics said that the wise man alone is free ; and in 
fact the spirit is not at all free when it is filled with a great 
passion, for one cannot then will as he should, that is to say, 
with the deliberation which is requisite. Thus God alone is 
perfectly free, and created spirits are so, only to the extent 
that they are superior to their passions. And this freedom 
concerns properly our understanding. But the freedom of 
spirit, opposed to necessity, concerns the naked will, and in so 
far as it is distinguished from the understanding. This is 

1 Simon Episcopius, 1583-1643. The piece referred to is the Be libero arbi- 
trio, particularly the second chapter ; it is found in his Opera Theologica, Vol. 
1, p. 198, Div. II., 2d ed. London and Rotterdam, 1665-1678, 2 vols., fol. — Tr. 



180 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

what is called free-will (franc-arbitre) and it consists in this, 
that we will that the strongest reasons or impressions which 
the understanding presents to the will do not prevent the act 
of the will from being contingent, and do not give it an abso- 
lute, and, so to speak, metaphysical necessity. And it is in 
this sense that I am accustomed to say that the understanding 
can determine the will, according to the prevalence of percep- 
tions and reasons, in a manner which, even where it is certain 
and infallible, inclines without compelling. 1 

§ 9. Ph. It is well also to consider that no one has yet 
thought of taking as a free agent a ball, whether in motion by 
the stroke of a racket or at rest. This is because we do not 
conceive of a ball as thinking or as having any volition, which 
makes it prefer motion to rest. 

Th. [If that were free which acts without hindrance, a ball 
once in motion in a level horizon would be a free agent. But 
Aristotle has already well remarked that to call acts free, we 
demand not only that they be spontaneous, but further that 
they be deliberate. 2 '] 

Ph. This is why we consider the motion or rest of balls 
under the idea of a necessary thing. 

Th. [The appellation necessary requires as much circumspec- 
tion as that of free. This conditional truth, viz.: supposing the 
ball to be in motion in a level horizon without hindrance, it will 
continue the same motion, may pass as in some sort necessary, 
although at bottom this consequence is not entirely geometri- 
cal, being only presumptive, so to speak, and based upon the 
wisdom of God who changes not his influence without a 
reason, which it is presumed is not at present to be found. 
But this absolute proposition : the ball here is now in motion in 
this plane, is only a contingent truth, and in this sense the ball 
is a contingent, not a free, agent.'] 

§ 10. Ph. Suppose that a man, while in a profound sleep, is 
carried into a room, where is a person, whom he much longs to 

i Cf. Essais de Thtodicee, Pt. I., §§ 51, 52, Gerhardt, 6, 130-131 ; Erdmann, 
517 ; also Eduard Dilknann, Eine neue Darstellung der Leibnizischen Monad- 
enlehre auf Grund der Quellen, pp. 416 sq. ; Leipzig: 0. R. Reisland, 1891. — 
Tr. 

2 Cf. Eth. Nic, III., 4, ad fin., 5; 1111 sq.; translation by F. H. Peters, 
M.A., London : C. Kegan Paul & Co., 1881. — Tk. 



xxi] ON HUMAN UNDERSTANDING 181 



see and to meet, and that the door is locked upon him ; this 
man wakes up and is delighted to find himself with this per- 
son, and lives thus in the room with pleasure. I think no one 
presumes to doubt that he remains voluntarily in that place. 
Yet he is not at liberty to go out if he wishes. Thus freedom 
is not an idea belonging to volition. 

Tit. [I find this example very well chosen to show that in a 
sense, an act or a state may be voluntary without being free. 
Still when philosophers and theologians dispute upon jfree ivill, 
they have altogether another sense in view.] 

§ 11. Ph. Freedom is wanting when paralysis prevents the 
limbs from obeying the determination of the mind, although, 
in the case of the paralytic even, to remain sitting still might 
be voluntary so long as he prefers sitting still to changing 
his place. Voluntary is not then opposed to necessary, but to 
involuntary. 

Tli. [This precision of expression would be agreeable enough 
to me, but usage is far from it ; and those who oppose freedom 
to necessity, mean to speak not of external acts, but of the act 
itself of willing.] 

§ 12. Ph. A man awake is no more at liberty to think or 
not to think, than he is at liberty to prevent or not to prevent 
his body from touching any other body. But to transfer his 
thoughts from one idea to another is often within his deter- 
mination. And in that case he is as much at liberty as regards 
his ideas, as he is as regards the bodies upon which he rests, 
being able to transfer himself from one to the other as the 
fancy arises. There are, however, ideas, which, like certain 
(bodily) movements, are so fixed in the mind, that, in certain 
circumstances, you cannot avoid them whatever effort you 
make. A man upon the rack is not at liberty to put aside the 
idea of pain, and sometimes a violent passion acts upon our 
mind as the most violent wind acts upon our body. 

Tli. [There is order and connection in ideas, as there is in 
(bodily) movements, for the one corresponds perfectly to the 
other, although the determination in the movements be uncon- 
scious and free, or with choice in the thinking being whom good 
and evil only cause to incline without forcing him. For the soul, 
while representing bodies, preserves its (own) perfections, and 
although dependent upon the body (in seizing the good) in the 



182 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

voluntary acts, it is independent and makes the body depend 
upon itself in others. But this dependence is only metaphysical, 
and consists in the considerations which God has for the one 
while ruling the other, or rather for both, according to the 
original perfections of each ; whilst physical dependence would 
consist in an immediate influence, which the one would receive 
from the other on which it depends. For the rest, there come 
to us involuntary thoughts, partly from outside by means of 
objects which strike our senses, and partly from within by 
reason of the impressions (often insensible) which remain 
from preceding perceptions whose action continues and which 
mingle with those which appear for the first time. As regards 
these we are passive, and even when we wake up, images 
(under which designation I include not only the representa- 
tions of figures, but also those of sounds and other sensible 
qualities) come to us, as in dreams, without being called. 
The German language calls them ftiegende Gedanlcen, that is, 
flying thoughts (pensees volantes), which are not within our 
control, and among which there are sometimes many absurdi- 
ties which raise scruples in good people, and furnish exercise 
to casuists and directors of consciences. It is as in the magic 
lantern, which makes figures appear upon the wall according 
as something within is turned. But our mind, perceiving 
some image which recurs to it, may say : stop there, and, so to 
speak, arrest it. Moreover, the mind enters, as seems good 
to itself, into certain trains of thought, which lead it on to 
others. But this is true only when internal or external impres- 
sions do not at all prevail. It is true that in this thing men 
differ very much, both according to their temperament and 
according as they have exercised their control, so that one can 
master impressions where another lets them go. 

§ 13. Ph. Necessity takes place wherever thought is wholly 
wanting. And this necessity, when found, is an agent capable 
of volition, and when the commencement or continuation of 
any action is contrary to the preference of his mind, I call it 
convulsion; when the hindering or stopping of an action is 
contrary to his volition, I may call it restraint. Agents which 
have absolutely neither thought nor volition are in all respects 
necessary agents. 

Th. [It seems to me that, properly speaking, although 



ch. xxi] ON HUMAN UNDERSTANDING 183 

volitions are contingent, necessity should not be opposed to 
volition, but to contingency, as I have already remarked in § 9, 
and that necessity should not be confounded with determina- 
tion, for there is no less connection or determination in thoughts 
than in movements (to be determined being a wholly different 
thing from being pushed or forced by compulsion). And if 
we do not always notice the reason which determines us or 
by which we determine ourselves, it is because we are as 
little capable ourselves of perceiving the entire play of our 
mind and its thoughts, very often imperceptible and confused, 
as we are of recognizing all the machinery which nature causes 
to play in the body. Thus, if by necessity, you mean the cer- 
tain determination of man, which a perfect knowledge of all 
the circumstances within and without could make a perfect 
mind foresee, it is certain that thoughts being as determined 
as the motions they represent, every free act would be a neces- 
sary act. But necessity must be distinguished from contingency 
although determined ; and not only are contingent truths not 
at all necessary, but further, their connections are not always 
of an absolutely necessary character ; for it must be admitted 
that there is some difference in the manner of determining 
between consequences which take place in necessary matter 
and those which take place in contingent matter. Geometrical 
and metaphysical consequences necessitate, but physical and 
.moral incline without necessitating; the physical even having 
something of the moral and voluntary as related to God, since 
the laws of movement have no other necessity than that of (the 
principle, or choice, of — Te.) the best. Now God chooses freely 
although he is determined to choose the best ; and as bodies 
themselves do not choose (God having chosen for them), usage 
has decided that they be called necessary agents, to which I am 
not opposed, provided we do not confound the necessary and 
the determined, and do not suppose that free beings act in 
an indeterminate manner, an error which has prevailed in cer- 
tain minds and which destroys the most important truths, even 
this fundamental axiom : that nothing happens without reason, 
without which neither the existence of God nor other great 
truths could be satisfactorily demonstrated. As for compulsion 
it is well to distinguish two kinds, the one physical, as when 
a man is carried in spite of himself into prison, or thrown 



184 LEIBNITZ'S CRITIQUE OP LOCKE [bk. ii 

down a precipice ; the other moral, as, for example, the con- 
straint of a greater evil, and this act, 1 although in a sense 
forced, does not cease to be voluntary. 2 One may be compelled 
also, by the consideration of a greater good, as when a man is 
tempted by proposing to him a too great advantage, although it 
is not customary to call this constraint.] 

§ 14. Ph. Let us see now if we cannot put an end to that 
long agitated, and in my opinion very unreasonable, because 
unintelligible, question : WJiether man's will is free or no. 

Th. [There is much reason for the exclamation with respect 
to the strange manner of men who torment themselves by agi- 
tating badly conceived questions : They seek for what they know, 
and knoto not for ivhat they seek.~\ 

Ph. Freedom, which is only a power, belongs only to agents 
and cannot be an attribute or modification of the will, which is 
itself nothing else than a power. 

Th. [You are right, sir, according to the proper use of 
words. One can, however, in some measure excuse received 
usage. Thus it is customary to attribute power to heat or to 
other qualities, i.e. to the body in so far as possessed of that 
quality : and in like manner the intent here is to ask if man is 
free in willing.] 

§ 15. Ph. Freedom is the power a man has of doing or not 
doing any act conformably to his will. 

Th. If men understood only that by freedom, when they ask 
whether the will, or the arbiter is free, their question would be 
truly absurd. But you will see presently what they ask, and 
indeed I have already touched upon it. It is true but by 
another principle, that they (at least many) do not cease to 
ask for the absurd and the impossible, in desiring a freedom 
of equilibrium absolutely imaginary and impracticable, and 
which indeed would not serve them, were it possible for them 
to have it, i.e. to have the freedom of willing against all the 
impressions which can come from the understanding, which 
would destroy true freedom together with the reason, and lower 
us below the beasts. 

1 Geiiiarclt reads: "et cette action, quoyque forcee en quelque facon"; 
Erdmann and Jacques: " car Taction, qu'elle fait faire," i.e. for the act which 
it makes you do. — Tr. 

2 Cf. Kant, Kritik d.prakt. Vernunft, Th. I., Bd. I., Hpst. 1, § 6, Anm.; 
translation by T. K. Abbott, 4th ed., revised and enlarged. London : Longmans, 
1889. — Tr. 



ch. xxi] ON HUMAN UNDERSTANDING 185 

§ 17. Ph. He who should say that the power of speaking 
directs the power of singing, and that the power of singing l 
obeys or disobeys the power of speaking, would express him- 
self in as proper and intelligent a manner, as he who says, as 
has been usual, that the will directs the understanding, and 
that the understanding obeys or disobeys the will. § 18. 
Nevertheless this manner of speaking has prevailed, and has 
caused, if I am not mistaken, much confusion, although the 
power of thinking operates no more upon the power of choos- 
ing and the contrary, than the power of singing upon that of 
dancing. § 19. I grant that this or that thought may furnish 
man the occasion of exercising his power of choosing and that 
the mind's choice may be the cause of its actually thinking on 
this or that thing, just as actually singing a certain tune may 
be the occasion of dancing such a dance. 

Th. [There is a little more than the furnishing of occasions, 
since there is some dependence ; for you can will only what 
you find to be good, and according as the faculty of under- 
standing is improved the choice of the will is better, as on the 
other hand, according as man has vigor of will he determines 
his thoughts according to his choice, instead of being deter- 
mined and carried away by involuntary perceptions.] 

Ph. Powers are relations, not agents. 

Th. [If the essential faculties are only relations and add 
nothing whatever to the essence, the qualities and the faculties 
that are accidental or subject to change are something else, and 
we may say of these last that the one often depends upon the 
other in the exercise of their functions.] 

§ 21. Ph. In my opinion the question should not be, whether 
the will is free, — that is to speak in a very improper manner, 
— but whether the man is free. That granted, I say that so 
long as any one can by the direction or choice of his mind 
prefer the existence of an action to its non-existence, and the 
contrary, i.e. can make it exist or not exist according as he 
wills, so long he is free. And we can scarcely say how we 
could possibly conceive a being freer than so far as he is able 
to do what he wills. So that man seems to be as free in refer- 

1 Gerhardt reads: "parler," a MS. or typographical error; cf. Locke, 
Philos. Works (Bohn's ed.), Vol. 1^ p. 370. Erdmann and Jacques read: 
" chanter," which the translation follows. — Tr. 



186 LEIBNITZ'S CEITIQUE OF LOCKE [bk. ii 

ence to those actions which, depend npon this power he finds 
in himself, as it is possible for freedom to make him, if I may 
so express myself. 

Th. [When we reason about the freedom of the will or upon 
free-will (franc arbitre), we do not ask if man can do what 
he wills, but if there is enough independence in his will itself. 
We do not ask if he has free limbs or elbow-room, but if he 
has a free spirit, and in what it consists. In this respect one 
intelligence might be freer than another, and the supreme 
intelligence will exist in perfect freedom of which creatures 
are not at all capable.] 

§ 22. Ph. Men naturally inquisitive, and who love to remove 
as much as they can from their minds the thought of guilt, 
although it be by reducing themselves to a state worse than 
that of a fatal necessity, are not, however, satisfied with this. 
Unless freedom extends still farther, it is not to their taste, 
and in their opinion it is a very good proof that man is not at 
all wholly free, unless he has as well the freedom to will as that 
of doing what he wills. § 23. Concerning which I believe- 
that man cannot be free in reference to this particular act of 
willing an action which is in his power, when this action has 
been once proposed to his mind. The reason therein is wholly 
manifest, for the action depending upon his will, must una- 
voidably exist or not exist, and its existence or non-exist- 
ence following without fail exactly the determination and 
choice of his will, he cannot avoid willing the existence or 
non-existence of this action. 

Th. [I should think he could suspend his choice, and that 
this happens very often ; above all, when other thoughts inter- 
rupt deliberation : thus, although the action deliberated upon 
necessarily exists or not, it does not at all follow that you 
must necessarily determine upon its existence or non-existence ; 
for non-existence may happen again for want of resolution. 
Thus the Areopagites actually released the man whose case 
they had found too difficult to decide, deferring it to a term 
far distant, and taking a hundred years to consider it.] 

Ph. In making man free in this fashion, I mean in making 
the act of willing depend upon his will, another will or ante- 
rior faculty of volition is necessary in order to determine the 
acts of this will, and another to determine that, and thus to 



ch. xxi] ON HUMAN UNDERSTANDING 187 

infinity ; for wherever you stop, the actions of the last will 
could not be free. 

Th. [It is true you speak incorrectly when you speak as if 
we willed to will. We do not will to will, but we will to do, 
and if we willed to will, we should will to will to will, and 
this would go on to infinity : meanwhile it is not necessary to 
conceal that by some voluntary acts we contribute often indi- 
rectly to other voluntary acts, and although one cannot will 
what he will, as he cannot even judge what he will, 1 he can, 
however, so act in advance that he judges or wills at the time 
what he would wish to be able to will or judge to-day. Men 
attach themselves to persons, lectures, and considerations favor- 
able to a certain party, they give no attention to that which 
comes from the opposite party, and by these addresses and a 
thousand others which they employ, most frequently without 
definite design and without thought, they succeed in deceiving 
themselves or at least in changing and converting or per- 
verting themselves according to what they meet.] 

§ 25. Ph. Since then it is evident that man is not at lib- 
erty to will to will or not, the next thing demanded is, whether 
man is at liberty to will which of the two he pleases, for example, 
motion or rest? But this question is in itself so visibly absurd 
that it may suffice to convince any one who will reflect that 
freedom in no case concerns the will. For to ask whether a man 
is free to will what he pleases, motion or rest, speech or silence, 
is to ask whether a man can will what he wills, or be pleased 
with that with which he is pleased, a question which, in my 
opinion, needs no answer. 

Th. [It is true, nevertheless, that men find here a difficulty 
which deserves to be removed. They say that after having 
known and considered all, it is still within their power to will 
not only what pleases them the most, but furthermore wholly 
the contrary, merely to show their freedom. But you must 
consider that this caprice or obstinacy, or at least this reason 
which hinders them from following other reasons, also enters 
into the balance and makes that please them which would 
otherwise not do so, so that choice is always determined by 
perception. They do not then will what they would, but what 

x The French is: " et quoyqu' on ne puisse point vouloir ce qu' on veut, 
comme on ne peut pas menie juger ce qu' on veut." — Tr. 



188 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

pleases, although the will can contribute indirectly and as it 
were from afar to make anything pleasurable or otherwise, as 
I have already remarked. And as men scarcely recognize all 
these separate considerations, it is not astonishing that the 
mind is so perplexed in regard to this matter which has so 
many concealed windings.] 

§ 29. Ph. When men ask what it is that determines the 
will, the true reply is, the mind. If this answer is not satis- 
factory, it is plain that the meaning of the question reduces to 
this : Wliat moves the mind on each particular occasion to deter- 
mine to such particular motion or rest its general power of direct- 
ing its faculties towards motion or rest? To this I reply that 
what leads us to remain in the same state or continue the 
same action, is solely the present satisfaction we find therein. 
On the other hand, the motive which incites to change is 
always some uneasiness. 

Th. [This uneasiness, as I have shown (in the preceding 
chapter), is not always a displeasure, as ease when found is 
not always a satisfaction or pleasure. It is often an insensible 
perception, which cannot be distinguished or recognized, which 
makes us lean to one side rather than the other, without our 
being able to give a reason for so doing.] 

§ 30. Ph. Will and desire should not be confounded : a man 
desires to be freed from the gout, but understanding that the 
removal of this pain may cause the transfer of a dangerous 
humor into some more vital part, his will cannot be determined 
to any action, which may serve to remove this pain. 

Th. [This desire is a kind of an inclination of will (yelleite) 1 
as compared with a complete volition. We should will, for 
example, if there were no greater evil to be feared, if we 
obtained what we wish, or if perhaps there were a greater 
good to be hoped for if we went forward. But we can say 
that man wills to be delivered from the gout with a certain 
degree of volition, but which does not always go on to the last 
effort. This volition is called Velleity when it includes some 
imperfection or impotency.] 

§ 31. Ph. It is well to consider, however, that what deter- 
mines the will to act is not the greater good, as is ordinarily 
supposed, but rather some actual uneasiness, and ordinarily 
1 Cf. New Essaijs, Book. II., chap. 20, § 6, Ph. and note, ante, p. 168. — Tr. 



en. xxi] ON HUMAN UNDERSTANDING 189 

that which is most pressing. We may give it the name of 
desire, which is really an uneasiness of mind, caused by the 
want of some absent good, over and above the desire of being 
freed from pain. All absent good does not produce a pain 
proportionate to the degree of excellence which it has or which 
we acknowledge it to have ; whilst all pain causes a desire 
equal to itself; because the absence of good is not always an 
evil, as is the presence of pain. Therefore we can look upon 
and consider an absent good without pain. But in proportion 
as there is anywhere desire, so is there uneasiness. § 32. Who 
is there who has not felt in desire what the wise man says 
of hope, "that being deferred it makes the heart sick" 
(Prov. 13:12) ? Rachel cries "Give me children, or I die " 
(Gen. 30:1). § 34. When man is perfectly content with 
the state he is in, or when he is absolutely free from all 
uneasiness, what will can remain to him but to continue 
in that state ? Thus the wise Author of our being has 
put in men the inconvenience of hunger and thirst and other 
natural desires, in order to arouse and determine their wills to 
the proper conservation and continuation of their species. 
" It is better to marry than to burn," says St. Paul (1 Cor. 7:9). 
So true it is that the present sensation of a little burning has 
more power over us than the attractions of greater pleasures 
looked at in the distance. § 35. It is true that this maxim, 
it is the good and the greatest good which determines the 
will, is so firmly established that I am not at all surprised at 
having formerly regarded it as beyond doubt. But after strict 
inquiry I am forced to conclude that the good and the greatest 
good, although judged and acknowledged such, does not deter- 
mine the will ; unless coming to desire it in a manner propor- 
tional to its excellence this desire makes us uneasy at our 
deprivation of it. Suppose a man convinced of the utility of 
virtue so far as to see that it is necessary to the man who pro- 
poses anything great in this world, or hopes to be happy in 
the other : but until this man hungers and thirsts after right- 
eousness, his will will never be determined to any action in 
search for this excellent good, and any other uneasiness com- 
ing in the way will drag his will to other things. On the 
other hand, suppose a man given to wine considers that by 
leading the life he leads he is ruining his health and wasting his 



190 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

property, that he is coming to be dishonored in the world, to 
bring upon himself disease and to fall at last into poverty 
until he no longer has wherewith to satisfy this passion for 
drink which so strongly possesses him : nevertheless, the 
returns of uneasiness which he feels in being absent from his 
companions in debauch, drag him to the tavern at the hours he 
has been wont to go there, though at the time he has before 
his eyes the loss of his health and estate, and perhaps even 
that of the happiness of the other life, happiness which he 
cannot regard as a good inconsiderable in itself, since he 
admits that it is much more excellent than the pleasure of 
drinking or the vain chatter of a company of debauchees. It is 
not then for want of casting the eyes upon the sovereign good 
that he persists in this intemperance ; for he sees it and 
acknowledges its excellence, to the extent that during the 
time that intervenes between his drinking hours, he resolves 
to apply himself to the search for this sovereign good ; but 
when the uneasiness of being deprived of his accustomed 
pleasure comes to torment him, this good which he acknowl- 
edges more excellent than that of drinking, has no longer 
power over his mind, and it is this actual uneasiness which 
determines his will to the action to which it is accustomed, 
and which thereby making very strong impressions prevails 
again at the first occasion, although at the same time he binds 
himself, so to speak, by secret promises no longer to do the 
same thing, and imagines that this will be the last time that 
he will act against his highest interest. Thus he finds himself 
from time to time reduced to saying : 

Video meliora proboque, 
Deteriora sequor. 1 

I see the better way, I approve it, and I take the worse. 
This sentence which we acknowledge as true, and which is 
only too well confirmed by a constant experience, is easy to 
understand in this way, and there is perhaps no other sense in 
which it can be taken. 

Tli. [There is something beautiful and solid in these consid- 
erations. But I would not have you believe on that account 
that we must abandon those ancient axioms that the will 

1 Ovid, Metamorph. 7 : 21. — Tn. 



en. xxi] ON HUMAN UNDERSTANDING 191 

follows the greatest good, or that it flies from the greatest evil 
that it perceives. The source of the little application to true 
goods arises mainly from the fact that in matters and on the 
occasions where the senses act but little, the greater part of our 
thoughts are, so to speak, surd 1 (I call them cogitationes ccecce 
in Latin) i.e. void of perception and feeling, and consisting 
in the wholly empty employment of characters, as happens in 
the case of those who make algebraic calculations without con- 
sidering from time to time that the geometrical figures in 
question and the words ordinarily produce the same effect in 
this regard as the characters of arithmetic or algebra. One 
often reasons in words without having quite the same object 
in mind. Now this knowledge cannot move ; something living 
is necessary in order to arouse us. But thus it is that men 
most frequently think of God, of virtue, of happiness ; they 
speak and reason without definite ideas. Not that they can- 
not have them, since they are in their mind. But they do not 
trouble themselves to press their analysis. Sometimes they 
have ideas of an absent good or evil, but very feeble. It is 
then no wonder that they are scarcely affected. Thus if we 
prefer the bad it is because we perceive the good which it 
includes without perceiving either the bad therein or the good 
in the contrary consideration. We assume and believe, or 
rather we make the statement merely upon another's belief, or 
at most upon belief in the memory of our past reasonings, that 
the greatest good is on the better side, or the greatest evil on 
the other. But when we do not look at these at all, our 
thoughts and reasonings contrary to the feeling are a kind of 
psittacism 2 which furnishes nothing at present to the mind ; 
and if we take no measures to remedy it, it is idle talk, as I 
have already remarked above (Bk. I., chap. 2, § 11), and the 
most beautiful precepts of morality together with the best 
rules of prudence take effect only in a soul which is sensible 
(either directly, or, because that cannot always be, at least in- 
directly, as I shall show presently) and which is no longer 
sensible to that which is contrary thereto. Cicero well says 

1 The French is : " sourdes." Cf. p. 193, near the end of Th. — Tr. 

2 Littre thus defines " psittacisme," quoting this passage and the one further 
on, § 37, Th., by way of illustration: "Etat d'esprit danslequelon ne pense ou 
ne parle qu'en perroquet," i.e. a state of the mind in which one thinks or 
speaks only as a parrot. — Tr. 



192 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

somewhere x that if our eyes could see the beauty of virtue, we 
should love it warmly ; but that uot being at all the case, nor 
anything equivalent, we must not be astonished if in the strug- 
gle between the flesh and the spirit, the spirit so many times 
yields, since it does not clearly perceive its advantages. The 
struggle is nothing else than the opposition of different ten- 
dencies, which spring from confused and distinct thoughts. 
Confused thoughts often make themselves clearly felt, but 
our distinct thoughts are ordinarily clear only potentially ; 
they might be clear, if we would apply ourselves to the 
penetration of the sense of the words or characters ; but not 
doing so, either through negligence, or because of the shortness 
of time, we oppose mere words, or at least, too feeble images 
to living feelings. I knew a man influential in church and 
state, whose infirmities made him resolve to diet ; but he ad- 
mitted that he had not been able to resist the odor of the 
viands, which, passing before his apartment, were carried to 
others. It is doubtless a disgraceful weakness, but it is just 
what men have done. But if the mind made good use of its 
advantages, it would triumph grandly. It would be necessary 
to begin with education, which should be so regulated as to 
render true good and true evil as sensible as possible, by in- 
vesting the notions which are formed of them with circum- 
stances more suited to this design; and a full-grown man who 
lacks this excellent education should commence rather late, 
than never, to seek pleasures enlightened and reasonable, in 
order to oppose them to those of the senses, which are con- 
fused but impressive. And in fact, divine grace itself is a 
pleasure 2 which gives light. Thus when a man is in the midst 
of good impulses, he ought to make laws and regulations for 

1 Perhaps in De Fin., 2, 16, § 52: " Oculorum, inquit Plato, est in nobis 
sensus acerrimus, quibus sapientiam non cernirnus. Quam ilia ardentes amores 
excitaret sui, si videretur," where, however, the discourse is concerned with 
the particular virtue of wisdom, rather than with virtue in general. The pas- 
sage of Plato referred to is in the Phxdrus, 250 D. Of. also, De Off., 2, 37: 
" Quis non admiretur splendorem pulchritudmemque virtutis " ; and De Off., 
1, 5: " Formam quidem ipsam, Marce fill, et tanquam faciem honesti vides; 
quae si oculis cerneretur, mirabiles amores excitaret sapiential." — Tr. 

2 Of. Spinoza, Ethica, Part V., Props., 32, 33, sq.; translation byR. H. M. 
Elwes, The Chief Works of Benedict de Spinoza, Vol. 2, pp. 263 sq. (Bohn's 
Philos. Library), London: George Bell & Sous, 1884. The best edition of 
Spinoza's Works is that of Van Vloten and Land, The Hague, 1882-1883. — Tn. 



ch. xxi] ON HUMAN UNDERSTANDING 193 

the future, and execute them rigorously, tearing himself away 
from those causes able to corrupt him, either brusquely or 
gradually, according to the nature of the circumstances. A 
journey expressly undertaken will cure a lover ; a retreat will 
draw us from the companions who support us in some bad in- 
clination. Francis of Borgia, General of the Jesuits, who has 
at last been canonized, being wont to drink largely when he 
was a man in high life, reduced himself little by little upon a 
small scale, when he thought of retiring (from the world) by 
causing a drop of wax to fall daily into the bottle which he 
was wont to empty. To dangerous sensibilities we shall op- 
pose some other innocent sensibility, as agriculture, garden- 
ing ; we shall shun idleness ; we shall collect curiosities of 
nature and art ; we shall make experiments and researches ; 
we shall engage in some indispensable occupation, if we have 
none, or in conversation, or useful and agreeable reading. 
In a word, we must profit from good impulses as from the 
voice of God which summons us to make effective resolutions. 
And as we cannot always analyze the notions of true goods 
and true evils until we perceive the pleasure and pain they in- 
clude, we must once for all make this law in order to be moved 
by them : to attend to and follow henceforth the conclusions 
of reason once for all understood, although perceived after- 
ward and ordinarily only by thoughts surd 1 merely, and desti- 
tute of sense attractions ; and this in order to put yourselves 
finally in possession of control over the passions as well as of the 
insensible inclinations or uneasinesses, by acquiring this habit 
of acting according to reason, which makes virtue pleasant, 
and as it were natural. But it is not our business here to give 
and teach the precepts of morality, or the spiritual directions 
and address for the exercise of true piety ; it is enough that 
in considering the procedure of our soul, we see the source of 
our weaknesses, the knowledge of which gives, at the same 
time, that of their remedies.] 

§ 36. Ph. The present uneasiness which presses us, works 
only upon the will, and naturally determines it in view of that 
happiness to which we all aim in all our actions ; because every 
one regards pain and uneasiness (i.e. the restlessness, or rather 
inconvenience, which prevents us from being at our ease) as 

1 Cf. p. 191, near the beginning of Tn., and note. — Tr. 
O 



194 LEIBNITZ'S CRITIQUE OF LOCKE [bk. h 

incompatible with happiness. A little pain suffices to corrupt 
all the pleasures we enjoy. Consequently that which deter- 
mines incessantly the choice of our will to the succeeding 
action will always be the removing of pain, as long as we feel 
any touch of it; this removal being the first step towards 
happiness. 

Th. If you take your uneasiness or inquietude as a veritable 
displeasure, in this sense I do not admit that it is the sole in- 
centive. Most frequently these are the little insensible per- 
ceptions which might be called imperceptible pains if the 
notion of pain did not include apperception. These little im- 
pulsions consist in delivering themselves continually from 
little obstacles towards which our nature works without think- 
ing of them. This uneasiness consists in truth in this, that 
we feel without knowing it, which fact makes us act in passion 
as well as when we appear most tranquil; for we are never 
without some action and motion, which arises only from the 
fact that nature always labors to put herself more at her ease. 
And this it is which determines also before all consultation in 
the cases which appear to us the most indifferent, because we are 
never perfectly in suspense and we cannot be exactly equally 
divided between two cases. Now if these elements of pain 
(which degenerate into veritable pain or displeasure sometimes 
when they overgrow) were true pains, we should always be 
miserable in pursuing the good that we seek with uneasiness 
and spirit. But it is wholly the contrary; and as T have 
already said above (§ 6 of the preceding chapter), the mass 
of these continual little successes of nature, which puts it more 
and more at ease in reaching for the good and enjoying its 
image, or lessening the feeling of pain, is already a consider- 
able pleasure, and often worth more than the enjoyment even 
of the good; and very far from being obliged to regard this un- 
easiness as incompatible with happiness, I find that uneasiness is 
essential to the happiness of created beings which never con- 
sists in complete possession, 1 — this makes them insensible, and 

1 Cf. the famous passage of Lessing, 1729-1781, regarding the ' search after 
truth, rather than its possession,' in the Theolog. Streitschriften, EineDuplik, 
1778, 1, ad fin., Werke, Bd.10, s. 19, Stuttgart, 1869: "Nicht die Wahrheit, in 
deren Besitz irgend ein Mensch ist, oder zu sein vermeint, sondern die auf- 
richtige Miihe, die er angewandt hat, hinter die Wahrheit zukomrnen, macht 
den Werth des Menschen. Denn nicht durch den Besitz, sondern durch die 



ch. xxi] ON HUMAN UNDERSTANDING 195 

as it were stupid, — but in a progress continuous and uninter- 
rupted towards the greatest good, which cannot fail to be ac- 
companied by a desire, or at least, a continual uneasiness, but 
which, as I have just explained, does not go so far as to incon- 
venience, but limits itself to those elements or rudiments of 
pain, partly unconscious, which do not cease to be sufficient to 
serve as an incentive and to arouse the will ; as does appetite 
in a man who is well when it does not go to that inconvenience 
which makes us impatient and torments us by a too great at- 
tachment to the idea of what Ave lack. These appetitions, small 
or great, are what are called in the schools motus primo primi, 
and are truly the first steps which nature makes us take not 
so much towards happiness as towards joy, for they relate only 
to the present ; but experience and reason teach us to rule 
these appetitions and to control them so that they may con- 
duce to happiness. I have already spoken to this effect (Book 
I., chap. 2, § 3). The appetitions are like the natural ten- 
dency of the stone, which goes the most direct, but not always 
the best path towards the centre of the earth, not being able 
to see beforehand that it will meet rocks upon which it will 
break in pieces, whilst it would approach its end more directly 
if it had mind and the means of turning aside from them. 
Thus it is that going straight towards present pleasure we 
sometimes fall over the precipice of misery. Hence, reason 
opposes thereto images of the greatest good or evil to come, 
and a firm resolution and habit of thinking before acting, and 
then of following what shall have been recognized as the best, 

jSTachforschung der Walirheit erweitern sich seine Krafte, worin allein seine 
immer wachsende Vollkommenheit besteht. Der Besitz macht ruhig, triige, 
stolz . . ." ; i.e. " Not the truth, in possession of which at any time a man is, 
or thinks he is, but the genuine effort he has made to discover the truth, con- 
stitutes the worth of the man. For not through possession, but through the 
search after the truth, are his powers expanded, wherein alone consists his ever 
growing perfection. Possession makes (him) quiet, lazy, proud ..." 

The real significance of this famous passage in relation to the problem of 
knowledge is not that knowledge is impossible, i.e. Agnosticism, for this is 
strictly the meaning of the term ; but rather that the attainment of truth is 
possible, and that the human mind, having in its very constitution infinite 
elements and a capacity for an infinite ideal, can never rest satisfied with any 
present attainment or form of expression as final, but must continue to strive 
after the perfect truth as embodied in the infinite. Cf. an article by the 
translator, entitled " Revelation, Inspiration, and Authority," in " The Andover 
Review," April, 1891. — Tr. 



196 LEIBNITZ'S CRITIQUE OF LOCKE [bk. u 

even when the sensible reasons of our conclusions are no longer 
present in the mind, and consist of scarcely more than feeble 
impressions or even of surd thoughts, which give words or 
signs destitute of an actual explanation, so that all consists in 
the : Consider it well, and in the : Be mindful; the first in 
order to the making of laws, the second for their following, 
even when you do not think of the reason which has called 
them into existence. It is, however, well to think of them as 
much as possible, in order that the soul may be filled with a 
rational joy and a pleasure accompanied with light.] 

§ 37. Ph. These precautions are doubtless so much the 
more necessary as the idea of an absent good can counter- 
balance the feeling of some uneasiness or displeasure by which 
we are at present tormented, only so far as this good arouses 
any desire in us. How many men there are to whose minds 
the unspeakable joys of paradise are represented by lively 
pictures which the}' recognize as possible and probable, who 
nevertheless would willingly content themselves with the hap- 
piness which they enjoy in this world. It is the uneasiness of 
their present desire getting the better of them and bearing 
them rapidly towards the pleasures of this life which deter- 
mines their wills to seek them : and during all this time, they 
are wholly insensible to the goods of the other life. 

Th. [This arises in part from the fact that men very often 
are but little persuaded ; and, although they say they are, a 
hidden unbelief reigns in the depths of their souls ; for they 
have never understood the excellent reasons which verify this 
immortality of souls, worthy of the justice of God, which is 
the foundation of true religion, or rather they no longer re- 
member that they understood them, one or the other of which 
conditions however is necessary in order to conviction. Few 
men indeed think that the future life, as true religion and 
indeed true reason teaches it, is possible, and they are still 
farther from thinking it probable, not to say certain. All that 
they do think about it is but a psittacism, or gross and vain 
images after the Mahometan fashion, in which they them- 
selves see little likelihood. For they are very far from being 
moved by them, as (according to report) were the soldiers 
of the Prince of the Assassins, the Old Man of the Moun- 



ch. xxi] ON HUMAN UNDERSTANDING 197 

tain, 1 who were carried away when fast asleep into a place full 
of delights, where, believing themselves in the paradise of Ma- 
homet, they were imbued by the angels or counterfeit saints with 
such opinions as this prince desired, and whence after having 
been stupefied anew they were carried to the place whence they 
had been taken ; this emboldened them afterwards to undertake 
everything, even attempts upon the lives of princes, enemies of 
their chief. I do not know whether this Lord 2 or Old Man of the 
Mountain was injured ; for not a few great princes may be named 
whom he had caused to be assassinated, although you may see 
in the English historians the letter, attributed to him, exon- 
erating King Richard I. of the assassination of a Count or 
Prince of Palestine, 3 whom this Old Man of the Mountain ad- 
mitted he had had killed because he had been insulted by him. 

1 The usual translatiou of " Sheikh-al Jebal," the title of the supreme ruler 
of the Assassins, a secret society whose distinguishing feature was the employ- 
ment of secret assassination against all enemies; a practice introduced by 
Hassan Ben Sabbah, the first chief of the sect. Otherwise the principles of 
the society were the same as those of the Ismaelites, viz. 1. No fixed rules 
of religion or morality, all actions indifferent, internal disposition alone of 
value. 2. Belief that the Immams of Ismael's line were now invisible, hence 
implicit obedience on part of true believers due to their vicegerents on earth. 
3. Allegorical interpretation of the Koran, defending or rejecting any doctrine 
at pleasure, as occasion required. 

The society was made up of seven ranks or orders : 1. The Sheikh ; 2. the 
Daial-Kirbal, or grand-priors ; 3. the Dais, or priors ; 4. Rejiks, associates 
not initiated, as were the former, into all the secret doctrines; 5. the Fecials, 
"devoted ones," a band of youths uninitiated aud blindly obedient to the 
chief; 6. Lasiks, or novices; 7. common people, laborers, and mechanics. On 
these was enjoined the most rigid observance of the Koran. The initiated 
regarded all positive religion and morality as worthless. The Feclais were the 
assassins proper. Whenever the chief wished for their service he had them 
intoxicated with hashish, or the hemp-plant, and transported into his splendid 
gardens, where they were surrounded with every sensual pleasure, and by this 
foretaste of Paradise which the chief alone could grant led to obey his slightest 
command implicitly, even to the surrender of their own lives. From this cir- 
cumstance they were called Hashishin, or hemp-eaters. This word the Euro- 
peans changed into Assassins, and thus it was transplanted into the Western 
languages with the signification of murderers. See Von Hammer, Geschiehte 
der Assassinen, 1818; Michaud, Histoire des Croisades, 2, pp. 465-484; 
F. Walpole, The Ansayrii, or Assassins, 3 vols., 1851 ; Gayard, Fragments 
relatifs a la Doctrine des Ismaelis, 1874; De Sacy, Memoir es de V Institut, 4, 
1818, discusses the etymology fully. — Tr. 

2 Gerhardt reads : " Seigneur ou Senior (Vieux) de la Montagne." — Tr. 

3 The Margrave Conrad" of Montferrat, one of Saladin's brave adversaries. 
Of. Gibbon, Decline and Fall, Milman's ed., chap. 59, and note 74, also Milman's 
note ; Weil, Gesch. d. Chalifen, Vol. 3, p. 423; Wilken, Gesch. d. Kreuzzuge, 
Vol.4, p. 485 s?. — Tr. 



198 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

Although that may be so, it was perhaps because of his great 
zeal for his religion that this Prince of the Assassins wished 
to give his people a favorable idea of paradise which should 
always accompany their thoughts of it and prevent them 
from being surd; without claiming on that account that they 
should believe that they had been in paradise itself. But 
supposing he had made this claim, it would not necessarily be 
astonishing if these pious frauds had been more efficacious than 
the truth badly managed. Yet nothing would be stronger than 
truth if we devoted ourselves to its complete knowledge and 
cultivation ; and we should have in it without doubt the means 
of strongly influencing men. When I consider how much 
ambition or avarice can accomplish in all those who once 
place themselves in this course of life, almost destitute of sen- 
sible and present attractions, I despair of nothing, and I hold 
that virtue would be infinitely more effective accompanied as 
it is by so many solid goods, if some happy revolution of the 
human race brought it for a day into demand and made it as 
it were fashionable. It is very certain that we could accustom 
the youth to find their greatest pleasure in the practice of vir- 
tue. And even grown up men could make themselves laws 
and a habit of conforming to them, which would influence them 
as strongly and with as much uneasiness if they were turned 
aside from them, as a drunken man would feel when he is 
prevented from going to the ale-house. I am very happy to 
add these considerations upon the possibility and even upon the 
ease of the remedies for our evils, in order not to assist in dis- 
couraging men from the pursuit of true goods by the mere 
exposition of our weaknesses.] 

§ 39. Ph. [Nearly everything consists in making constant 
the desire for true good.] And it rarely happens that any 
voluntary action is produced in us unless some desire accom- 
panies it ; this is why will and desire are so often confounded. 
But we must not regard the uneasiness which makes a part of, 
or which at least accompanies most of the other passions, as 
entirely excluded in this case. For hatred, fear, anger, envy, 
shame, have each their uneasiness, and thereby influence the 
will. I doubt if any one of these passions exists entirely alone. 
I believe indeed that it would be difficult to find any passion 
unaccompanied by desire. I am sure, however, that wherever 



ch. xxi] ON HUMAN UNDERSTANDING 199 

there is uneasiness there is desire. And as our eternity does 
not depend on the present moment, we look beyond the present, 
whatever be the pleasures which we actually enjoy, and desire, 
accompanying these glances anticipative of the future, always 
impels the will to follow ; so that even in the midst of joy 
that which maintains the action upon which the present pleas- 
ure depends, is the desire to continue it, and the fear of being 
deprived of it, and whenever a greater uneasiness than that 
takes possession of the mind it immediately determines the 
mind to a new action and the present pleasure is neglected. 

Th. [Many perceptions and inclinations concur in perfect 
volition, which is the result of their conflict. There are 
some imperceptible by themselves, whose mass makes an un- 
easiness which impels us without our seeing the cause; there 
are many joined together which tend to some object or which 
remove it, and then it is desire or fear accompanied also by 
an uneasiness, but which does not always go so far as pleasure 
or displeasure. 1 Finally, tliere are impulses really accompanied 
by pleasure and by pain, and all these perceptions are either 
new sensations or ideas resting upon some past sensation 
(accompanied or not by memory), which renewing the attrac- 
tions these same images had in the preceding sensations, renew 
also the former impulses in proportion to the vividness of the 
idea. From all these impulses results at last the prevailing 
effort which makes the will complete. But the desires and 
tendencies which are perceived are often also called voli- 
tions though less complete, whether they prevail and influence 
or not. It is thus easy to believe that volition can have but 
little force without desire and without aversion (firite) ; for 
such I believe we may call the opposite of desire. Uneasi- 
ness exists not only in the troublesome passions, as hatred, 
fear, anger, envy, shame, but further in their opposites, as 
love, hope, favor, and glory. We may say that whenever 
there is desire, there will be uneasiness ; but the contrary is 
not always true, because often one is in a state of uneasiness 
without knowing what he wants, and then there is no full- 
grown desire.] 

§ 40. Ph. Ordinarily the most pressing of the uneasinesses 

1 Gerhardt adds : " ou deplaisir." — Tr. 



200 LEIBNITZ'S CRITIQUE OE LOCKE [bk. n 

which are judged capable of being removed at that time deter- 
mines the will to action. 

Th. As the result of the balance makes the final deter- 
mination, I should think it may happen that the most press- 
ing uneasiness does not prevail; for though it might prevail 
over each of the opposed tendencies taken by themselves, the 
others united may overcome it. The mind can indeed use 
skilfully the dichotomies in order to cause sometimes the one, 
sometimes the others, to prevail, as in an assembly we can 
cause one party to prevail by plurality of votes, according as 
we shape the order of the question. It is true the mind 
ought to look far into the future ; for in the moment of 
struggle there is no time to use these artifices. All that then 
makes an impression, bears hard upon the balance, and helps 
to form a compound direction almost like that in mechanics, 
and which without some prompt diversion we cannot stop. 
Fertur equis auriga nee audit currus habenas. 1 

§ 41. Ph. If you ask further what it is that arouses desire, 
I reply, happiness and nothing else. Happiness and misery 
are the names of two extremes of whose utmost bounds we 
are ignorant. It is what "eye hath not seen, ear hath not 
heard, and the heart of man hath never conceived." 2 But both 
make in us lively impressions by means of different kinds 
of satisfaction and joy, of torment and sorrow, which for \\ 
brevity's sake I comprehend under the names of pleasure and 1 
pain, both of which happen to the mind as well as to the 
body, or, to speak more accurately, pertain only to the mind, I 
although sometimes they originate in the mind upon the 
occasion of certain thoughts, and sometimes in the body I 
from certain modifications of motion. § 42. Thus happiness, 
taken in its full extent, is the utmost pleasure of which we are |ij 
capable, as misery, taken in the same way, is the greatest 
pain we can feel. And the lowest degree of what can be 
called happiness is that state, in which delivered from all ffl 
pain, we enjoy such measure of present pleasure that we can- 
not be content with less. We call that a good which is 
adapted to produce in us pleasure, and we call that an evil 
which is adapted to produce in us pain. But it often happens 

i Verg. Georg. 1 : 514. — Tr. 21 Cor. 2:9.— Tr. 



ch. xxi] ON HUMAN UNDERSTANDING 201 

that we do not so name it when one or another of these goods 
or of these evils is found in competition with a greater good 
or a greater evil. 

Th. [I do not know whether the greatest pleasure is possi- 
ble. I should think rather that it can grow infinitely; for 
we know not how far our knowledge and our organs may 
be carried in all that eternity which awaits us. I should 
think then that happiness is a lasting pleasure ; which can- 
not exist without a continual progression to new pleasures. 
Thus of two, one of whom will advance incomparably more 
rapidly and by greater pleasures than the other, each will be 
happy in himself although their happiness will be unequal. 
Happiness is then so to speak a road through pleasures, and 
pleasure is only a step and an advance towards happiness, the 
shortest that can be made according to present impressions, 
but not always the best, as I said towards the end of § 36. 
One may miss the true road, in desiring to follow the short- 
est, as the stone going straight may meet too soon obstacles 
which prevent it from advancing directly towards the centre 
of the earth. Thus we know that it is the reason and the 
will which lead us towards happiness, but that feeling and 
appetite carry us only towards pleasure. Now although 
pleasure cannot receive a nominal 1 definition, any more than 
light or color, it can nevertheless receive like them a causal, 1 
and I believe that at bottom, pleasure is a feeling of perfec- 
tion and pain a feeling of imperfection, provided it be marked 
enough to make us capable of perceiving it : for the little 
insensible perceptions of a perfection or imperfection, which 
are like the elements of pleasure and pain, and of which I have 
spoken so many times, form the inclinations and propensities, 
but not yet the passions themselves. Thus there are insensi- 
ble inclinations and these we do not perceive; there are sensi- 
ble ones whose existence and object we know, but whose 
formation we do not feel, and there are confused inclinations 
which we attribute to the body, although there is always 
something corresponding in the mind ; finally, there are dis- 
tinct inclinations, which reason gives us, whose force and 
formation we feel ; and the pleasures of this kind which are 
found in the knowledge and production of order and harmony 
1 Of. New Essays, Bk. III., chap. 3, § 18. — Tr. 



202 LEIBNITZ'S CRITIQUE OE LOCKE [bk. 11 

are the most estimable. You are right in saying that in 
general all these inclinations, passions, pleasures and pains 
belong only to the mind or soul ; I will add, indeed, that their 
origin is in the soul itself, taking things in a certain meta- 
physical strictness, but that, nevertheless, you are right in say- 
ing that confused thoughts come from the body, because 
thereupon the consideration of the body — and not that of 
the soul — furnishes something distinct and explicable. The 
good is that which conduces or contributes to pleasure, as the 
evil is that which contributes to pain. But in collision with a 
greater good, the good of which we should be deprived would 
become in truth an evil, in so far as it should contribute to 
the pain which would spring from it. 

§ 47. Ph. The soul has the power of suspending the accom- 
plishment of some of these desires, and is consequently at lib- 
erty to consider one after another and to compare them. In 
this consists the freedom of man, and what we call, though in 
my view improperly, free-will ; and it is from the bad use we 
make of it that all this variety of mistakes, errors, and faults 
proceeds, into which we rush when we determine our will too 
promptly or too late. 

Th. The execution of our desire is suspended or stopped 
when this desire is not strong enough to move us and to over- 
come the trouble or inconvenience there is in satisfying it; 
and this trouble consists sometimes only in an inactivity or 
insensible lassitude which discourages without our taking 
notice of it, and which is greatest in persons reared in indo- 
lence or whose temperament is phlegmatic, and in those who 
are discouraged by age or by poor success. But when desire 
is strong enough in itself to move, if nothing prevents it, it 
can be stopped by contrary inclinations ; whether they consist 
in a simple propensity which is as it were the element or be- 
ginning of desire, or go as far as desire itself. But as these 
inclinations, these propensities, and these contrary desires are 
to be found already in the soul, it does not have them in its 
power, and consequently it could not resist them in a free and 
voluntary way in which the reason can share, if it had no 
other means of diverting the mind elsewhere. But how does 
it presume to do it in case of need ? For there is the point, 
especially when one is occupied with a very strong passion. 



ch. xxi] ON HUMAN UNDERSTANDING 203 

It is then necessary for the mind to be prepared in advance, 
and to find itself already in process of going from thought to 
thought, in order not to hesitate too much at a slippery and 
dangerous step. It is well for that reason to accustom our- 
selves in general not only to think as it were in passing of 
certain things in order the better to preserve the freedom of 
the mind ; but it is better to accustom ourselves to proceed 
methodically, and to fasten ourselves to a train of thoughts 
whose connection reason and not chance (i.e. insensible and 
casual impressions) makes. And for this purpose it is well 
from time to time to accustom ourselves to collect our thoughts 
and to raise ourselves above the present tumult of impres- 
sions, to go forth, so to speak, from the place where we are, to 
say to ourselves: "Die cur hie? respice finem, 1 where are we 
then ? or let us come to the purpose, 2 let us come to the point." 
Men would very often need some one officially appointed (as 
Philip, the father of Alexander the Great, had) to interrupt 
and call them to their duty. But in default of such an officer, 
it is well for us to be accustomed to render ourselves this ser- 
vice. Now being once in a condition to stop the effect of our 
desires and passions, i.e. to suspend (their) action, we can find 
means to combat them, whether by contrary desires or inclina- 
tions or by diversion, i.e. by occupations of another nature. 
It is by these methods and artifices that we become as it were 
masters of ourselves, and can make ourselves think and do at 
the time what we should wish to will and what reason com- 
mands. But it is always through determined paths, and never 
without a reason or by means of the imaginary principle of 
perfect indifference or equilibrium, in which some would make 
the essence of freedom to consist ; as if one could determine 
himself without a subject, and even against every subject, and 
go directly against the entire prevalence of impressions and 
propensities. Without a reason, I say, i.e. without the opposi- 
tion of other inclinations, or without being in advance dis- 
posed to turn aside the mind, or without any other means 
equally explicable ; (to act) otherwise is to recu 1 - to the chimer- 

1 Literally : Why are we here ? Consider the end ! — Tr. 
2 Erdmann and Jacques omit: "ou venons au propos," found in Ger- 
hardt.— Tr. 



204 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

ical, as in the empty faculties or occult qualities of the scho- 
lastics, in which there is neither rhyme nor reason.] 

§ 48. Ph. [I am also for this intelligent determination of 
the will by what is in the perception and the understanding.] 
To will and do conformably to the final result of a sincere 
examination is rather a perfection than a defect of our nature. 
And this so far from being a suppression or an abridgement 
of freedom, is its greatest perfection and advantage. And the 
more we are prevented from determining ourselves in this 
way, the nearer we are to misery and slavery. In fact, if you 
suppose in the mind a perfect and absolute indifference which 
cannot be determined by the final judgment which it makes of 
good or evil, you put it in a very imperfect state. 

Th. [All this is very much to my taste, and shows that 
the mind has not entire and direct power always to stop its 
desires, else it would never be determined, whatever examina- 
tion it might make, and whatever good reasons or efficacious 
sentiments it might have, and it would always remain irreso- 
lute and fluctuate eternally between fear and hope. It must, 
then, after all, be determined, and thus it could itself oppose 
only indirectly its desires, by itself preparing in advance the 
arms which fight them in time of need; as I have just ex- 
plained.] 

Ph. But a man is at liberty to lift his hand to his head or 
to let it lie quiet. He is perfectly indifferent regarding either 
of these acts, and it would be an imperfection in him if he 
lacked that power. 

Th. [To speak accurately, one is never indifferent regard- 
ing two alternatives, 1 whatever they may propose ; for exam- 
ple, turning to the right or the left, 2 putting the right foot 
forward (as was necessary in the case of Trimalchio) or the 
left ; for we do the one or the other without thinking of it, 
and this is an indication that a concurrence of internal disposi- 
tions and external impressions (although insensible) deter- 
mines us to the side that we take. But the prevalence is very 

1 After "partis," Gerhardt reads: " quelsqu'on puisse proposer," which 
Erdmann and Jacques omit. — Tr. 

2 After " gauche," Gerhardt reads : " de mettre le pied droit devant (comme 
il falloit chez Trimalcion) ou le gauche," which Erdmann and Jacques omit. 
For the allusion c/. Petronius, Satyr icon, chap. 30. — Tr. 



ch. xxi] ON HUMAN UNDERSTANDING 205 

small, and in case of need it is as if we were indifferent in this 
respect, since the least sensible subject which presents itself 
to us is capable of determining us without difficulty to one 
rather than to the other ; and although there is a little trouble 
in lifting the arm to raise the hand to the head, it is so small 
that we overcome it without difficulty ; otherwise, I admit it 
would be a great imperfection if man were less indifferent, 
and if he were wanting in power to determine easily to raise 
or not to raise his arm.] 

Ph. But it would be as great an imperfection if he had the 
same indifference on all occasions, as when he would defend 
his head or his eyes from a blow, by which he saw he was 
about to be struck. [That is to say, it were as easy for him 
to stop this movement as others of which we have just spoken, 
and in which he is almost indifferent ; for that would make 
its influence insufficiently strong and prompt in time of need. 
Thus determination is useful to us, and, indeed, 1 very often 
necessary ; for if we were less determined on every sort of 
occasion, and as it were insensible to reasons drawn from the 
perception of good or evil, we would be without effective 
choice.] And 2 if we were determined by something else than 
the final result, which we have formed in our own mind accord- 
ing as we have judged a certain action good or evil, we should 
not be free. 

Tli. [Nothing is truer, and those who seek another free- 
dom know not what they ask.] 

§ 49. Ph. The superior beings who enjoy perfect happi- 
ness are determined in the choice of the good more strongly 
than we, and yet we have no reason to think them less free 
than ourselves. 

Th. [For this reason theologians say that these blessed 
substances are confirmed in the good and exempt from all 
danger of falling.] 

Ph. I believe indeed that, if it were proper for poor finite 
creatures like ourselves to judge of what an infinite wisdom 
and goodness could do, we could say that God himself can- 
not choose what is not good, and that the freedom of this all 

1 Gerhardt omits "meme," which Erdmann and Jacques insert after 
"et."— Tr. 

2 Gerhardt reads : "et"; Erdmann and Jacques, "comme."— Tk. 



206 LEIBNITZ'S CRITIQUE OF LOCKE [inc. n 

powerful being does not hinder him from being determined by 
what is best. 

Th. [I am so persuaded of this truth that I believe we can 
boldly assure ourselves of it, wholly poor and finite creatures 
that we are, and that we should be very wrong in doubting 
it ; for by so doing we should derogate from his wisdom, 
goodness and other infinite perfections. But choice, however 
determined the will be, should not be called necessarily and 
rigorously absolute; the prevalence of perceived good in- 
clines without necessitating, although considered as a whole, 
this inclination is determinate and never fails to produce its 
effect.] 

§ 50. Ph. To be determined by the reason to the best, 
is to be the freest. Who would wish to be foolish for the 
reason that a fool is less determined by wise reflections than 
a man of good sense ? If freedom consists in throwing off 
the yoke of reason, fools and madmen will be the only free- 
men; but I do not believe that for love of such freedom 
any one would wish to be a fool, save he who is one already. 

Tli. [There are people to-day who consider it clever to 
declaim against reason, and to treat it as an inconvenient 
pedant. I see little books, discourses about nothing, which 
make great pretensions, and I sometimes see verses even too 
beautiful to be employed in such false thoughts. In. fact, 
if those who mock at reason spoke in earnest, it would be a 
new kind of extravagance unknown to past centuries. To 
speak against reason is to speak against truth ; for reason is a 
concatenation of truths. It is to speak against one's self, 
against one's good, since the principal point of reason con- 
sists in knowing the truth and following the good.] 

§ 51. Ph. As then the highest perfection of an intelligent 
being consists in applying himself carefully and constantly to 
the search for true happiness, so the care we should employ 
not to take as real happiness that which is only imaginary, is 
the foundation of our freedom. The more we are bound to 
the invariable search for happiness in general which never 
ceases to be the object of our desires, the more our will finds 
itself freed from the necessity of being determined by the 
desire which bears us towards some particular good, until we 
have examined whether it agrees with or is opposed to our 
true happiness. 



ch. xxi] ON HUMAN UNDERSTANDING 207 

Th. The true good should always be the object of our 
desires, but there is room for doubt whether it is so : for often 
one thinks but little of it, and I have remarked here more 
than once, that unless appetite is guided by reason it tends to 
present pleasure and not to happiness, i.e. to enduring pleas- 
ure, although it tends to protract it ; see § 36 and § 41. 

§ 53. Ph. If some extreme disturbance takes entire pos- 
session of our mind, as the pain of a cruel torture, we are not 
enough masters of our mind. But in order to control our 
passions as much as possible, we should make our mind relish 
good and evil really and effectively, and not permit an ex- 
cellent and considerable good to escape our mind without leav- 
ing there some relish, until we have excited in ourselves 
desires proportioned to its excellence so that its absence 
renders us uneasy as well as the fear of losing it when we 
enjoy it. 

Tli. [That sufficiently agrees with the remarks I have 
just made in §§ 31 and 35, and with what I have said more 
than once of luminous pleasures, where we understand how 
they improve us without putting us in danger of some greater 
imperfection, as do the confused pleasures of sense, against 
which we must guard ourselves, especially when we have not 
learned by experience that we shall be able surely to avail 
ourselves of them.] 

Ph. And let no one say here that he cannot master his pas- 
sions nor hinder them from breaking loose and forcing him to 
act ; for what he can do before a prince or great man, he can 
do, if he will, when alone or in the presence of God. 

Th. [That remark is very good and worthy of frequent 
reflection.] 

§ 54. Ph. But the different choices men make in the world, 
prove that the same thing is not equally good for each of 
them. And if the interests of men did not extend beyond 
this life, the reason of this diversity which causes, for exam- 
ple, these to plunge into luxury and debauchery, and those to 
prefer temperance to pleasure, would arise only from the fact 
that they placed their happiness in these different things. 

Th. [It arises thence even now, although they all have or 
should have before their eyes this common object of the 
future life. It is true that the consideration of true happi- 



208 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

ness, even in this life, should suffice to make those who dis- 
card it prefer virtue to pleasure ; although the obligation 
would not then be so strong or so decisive. It is also true 
that men's tastes are different, and it is said that we should 
not dispute about tastes. But as these are only confused per- 
ceptions, we should hold fast to them only in the case of ob- 
jects found to be indifferent and incapable of harm ; otherwise, 
if one had a relish for poisons which would kill him or render 
him miserable, it would be ridiculous to say that his taste 
should not be called in question.] 

§ 55. Ph. If there is nothing to hope for beyond the grave, 
the inference is certainly very just : let us eat and drink, let 
us enjoy all that gives us pleasure, for to-morrow we die. 

Th. [There is something to be said, in my opinion, regard- 
ing this inference. Aristotle and the Stoics and many other 
ancient philosophers held another view, and I believe, indeed, 
that they were right. If there were nothing beyond this life, 
the peace of the soul and health of the body would not cease 
to be preferable to the pleasures which would be contrary 
thereto. And it is no reason whatever for neglecting a good 
because it will not endure forever. But I admit that there 
are cases where there would be no means of demonstrating 
that the most virtuous course would be the most useful. It is 
then the thought of God and of immortality only which ren- 
ders the obligations of virtue and justice absolutely indispen- 
sable.] 

§ 58. Ph. It seems to me that the present judgment we 
make of good and evil is always right. And' as for present 
happiness or misery, when reflection goes no farther, and all 
consequences are wholly put aside, man never chooses amiss. 

Th. [That is to say, if everything were limited to the pres- 
ent moment, it would not be right to refuse the pleasure which 
presents itself. In fact, I remarked above that all pleasure is a 
feeling of perfection. But there are certain perfections which 
bring with them greater imperfections. If some one devoted 
himself during his entire life to throwing peas against pins, in 
order to learn not to fail to make them pierce them, after the 
example of him to whom Alexander the Great caused to be 
given as a recompense a bushel of peas, this man would attain 
a certain perfection, but very slight and unworthy of being 



ch. xxi] ON HUMAN UNDERSTANDING 209 

compared with so many other very necessary perfections 
which he would have neglected. Thus the perfection which 
is found in certain present pleasures should yield especially 
to the regard for the perfections which are necessary ; in order 
that we be not plunged into misery, which is the state in 
which we go from imperfection to imperfection, from pain to 
pain. But if there be only the present, it would be necessary 
to be contented with the perfection which is present, i.e. with 
present pleasure.] 

§ 62. Ph. No one would voluntarily render his condition 
unhappy unless he were led by false judgments. I do not 
speak of mistakes which are the result of invincible error, 
and which scarcely deserve the name of false judgment, but 
of that false judgment which every man must confess in 
himself to be such. § 63. In the first place, then, the soul 
is mistaken when we compare present pleasure or pain with 
one to come which we measure by the different distance at 
which they are found with respect to us ; like a spendthrift 
heir who for the present possession of a little something 
would renounce a large heritage, which could not fail him.. 
Every one should recognize this false judgment, for the future 
will become present, and will then have the same advantage 
of nearness. If at the moment the man takes the glass in 
his hand, the pleasure of drinking were accompanied with the 
headache and pains in the stomach, which will follow in a 
few hours, he would not in the least wish to taste the wine. 
If a little difference in time causes so much illusion, with 
much stronger reason a greater distance will produce the 
same effect. 

Th. There is some congruity here between the distance 
of places and that of times. But there is also this difference, 
that visible objects diminish their action upon the sight 
very nearly in proportion to their distance, and it is not 
at all the same as regards the future objects which act upon 
the imagination and the mind. Visible rays are straight 
lines proportionally distant, but there are curved lines which 
after some distance appear to fall into the straight line 
and are no longer sensibly divergent: thus are made the 
asymptotes, whose apparent interval diverges from the straight 
lines, although in the truth of things they abide eternally 



210 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

separate. We find indeed that at last the appearance of ob- 
jects does not diminish in proportion to the increase of the 
distance, for the appearance soon 1 disappears entirely al- 
though the distance be not infinite. Thus a short distance of 
time robs us entirely of the future, as if the object had en- 
tirely disappeared. There often remains only the name in 
the mind and that kind of thoughts of which I have already 
spoken, which are surd, and incapable of making an impres- 
sion, unless you have attended to them methodically and 
habitually.] 

Ph. I do not speak here of that kind of false judgment 
by which what is absent is not only diminished but suddenly 
annihilated in men's minds, when they enjoy all they can 
obtain for the present, and then conclude that no evil will 
happen to them. 

TJi. [It is another kind of false judgment when the expec- 
tation of good or evil to come is annihilated, because the 
result drawn from the present is denied or made doubtful; 
but beyond that, the error which annihilates the thought of 
the future is the same thing as this false judgment of which 
I have already spoken, which arises from a too feeble repre- 
sentation of the future, which is considered only a little 
or not at all. For the rest, we might perhaps distinguish 
here between bad taste and false judgment, for often we 
do not even question whether the future good should be pre- 
ferred, and act only upon impression without presuming to 
come to the examination. But when we think, one of two things 
happens, either we do not continue sufficiently our thought, 
and we pass on without pressing the question which has 
been touched ; or we pursue the examination and form a 
conclusion. And sometimes in each case there remains greater 
or less self-condemnation : sometimes also there is no formido 
oppositi or scrupulousness at all, whether the mind turns aside 
at once, or is deceived by its prejudices.] 

§ 64. 2 Ph. The limited capacity of our mind is the cause 
of the false judgments we make in comparing good and evil. 
We cannot well enjoy two pleasures at once, and still less can 

1 Gerhardt reads after " entierement," "bientost," which Erdmann and 
Jacques omit. — Tr. 

2 Gerhardt. So also Locke, Philos. Works, Vol. 1, p. 402 (Bohn ed.). Erd- 
mann has § 29 : Jacques, § 59. — Tr. 



ch. xxi] ON HUMAN UNDERSTANDING 211 

we enjoy any pleasure in the time that we are beset by pain. 
A little bitterness mixed in the cup prevents us from tasting 
its sweetness. The evil we feel is always the worst ; we cry : 
Ah ! any other pain rather than this ! 

Th. [There is much variety in all this according to men's 
temperaments, the force of their feelings, and the habits they 
have contracted. A man who has the gout might be joyful 
because a large fortune fell to him, and a man who swims in 
delights, and who might live at his ease upon the earth, is 
plunged into sadness because of a disgrace at court. The fact 
is, joy and sadness arise from the result or from the prevalence 
of pleasures or pains, when there is a mixture of them. Lean- 
der scorned the inconvenience and danger of swimming over 
the sea at night, urged on by the attractions of the beautiful 
Hero. 1 There are people who can neither drink nor eat 2 nor 
satisfy other appetites without much pain, on account of some 
weakness or inconvenience ; and yet they satisfy these appe- 
tites even beyond necessity and just limits. Others are so 
effeminate or so delicate that they refuse pleasures with which 
any pain, disgust or any inconvenience is mingled. There 
are some persons who bravely place themselves beyond pains 
and pleasures present and ordinary, and act almost alone 
through fear and hope. Others are so effeminate that they 
complain of the least inconvenience, or run after the least sen- 
sible and present pleasure nearly like children. These are 
the people to whom the present pain or pleasure always ap- 
pears the greatest ; they are like preachers or panegyrists of 
little judgment, with whom, according to the proverb : The idol 
of the day is always the greatest saint of paradise. 3 But what- 
ever variety is found among men. it is always true tbat they 
act only according to present perceptions, and when the future 
impresses them, it is always by means of an image they have 
of it, or by resolution and habit which they have contracted 

i Of. Vergil, Georg. 3, 258 ; Ovid, Heroides, 18, 19 (17, 18, Ovid. Opera, ex 
recog. Rud. Merkelii, Vol. 1, p. 141 sq., Lipsise: B. G. Teubner, 1887) ; and, for 
" the final form "of " this poem of love and death," the poem of 340 hexameters 
by Musseus, the grammarian of the fifth century A.r>., an extended abstract of 
which is given in J. A. Symonds' Studies of the Greek Poets, Vol. 2, chap. 22, 
pp. 345-362. New York : Harper & Bros., 1880. — Tr. 

2 Gerhardt reads after "manger," " ou qui ne sauroient satisfaire d'autres 
appetits," which Erdmann and Jacques omit. — Tr. 

3 The italics are mine. — Tr. 



212 LEIBNITZ'S CRITIQUE OF LOCKE [inc. n 

in following even a simple name or other arbitrary character, 
without having any picture or natural sign, because it would 
not be without uneasiness, and sometimes without a feeling of 
chagrin, that they would oppose themselves to a strong reso- 
lution already made, and, above all, to a habit.] 

§ 65. Ph. Men are apt enough to diminish future pleasure, 
and to conclude in themselves that, when it comes to trial, it 
may perhaps not correspond to the hope it gives nor to the 
opinion they generally have of it ; having often found by their 
own experience that not only the pleasures which others have 
magnified have appeared to them very insipid, but that what 
has caused themselves much pleasure at one time, has offended 
and displeased them at another. 

Th. [These are mainly the reasonings of voluptuaries, but 
we ordinarily find that the ambitious and avaricious judge 
wholly otherwise honors and wealth, although they enjoy 
only moderately, and often, indeed, very little, these same 
goods when they possess them, being always occupied in going 
farther. I find it a beautiful invention of nature's architect 
to have rendered men so sensible to what appeals so little to 
their senses ; and if they could not become ambitious or avari- 
cious, it would be difficult in the present state of human nature 
for them to be able to become virtuous and reasonable enough 
to labor for their perfection in the face of the present pleas- 
ures which turn them aside from it. 

§ 66. Ph. As to things good or bad in their consequences 
and by their aptness to procure us good or evil, we judge 
them in different ways ; either when we judge them incapable 
of really doing us as much evil as in fact they do, or when 
we judge that while the consequence is important it is not so 
certain that it may not happen otherwise, or at least that it 
may not be avoided by some means, as by industry, address, 
change of conduct, repentance. 

Th. It seems to me that if by the importance of the conse- 
quence we understand that of the consequent, i.e. the great- 
ness of the good or evil that may follow, we must fall into the 
preceding kind of false judgment, in which future good or 
evil is poorly represented. Thus there remains only the sec- 
ond kind of false judgment, of which we shall presently treat, 
namely, that in which the consequence is doubtful.] 



ch. xxi] ON HUMAN UNDERSTANDING 213 

Ph. It would be easy to show in detail that the subterfuges 
which I have just alluded to are so many unreasonable judg- 
ments ; but I shall content myself with remarking in general 
that it is acting directly contrary to reason to hazard a greater 
good for a less [or to expose 1 ourselves to misery in order to 
acquire a little good or to avoid a little evil], and that, too, 
upon uncertain conjectures and before we have entered upon a 
due examination. 

Th. [As these are two heterogeneous considerations (i.e. 
considerations which cannot be compared with each other), 
that of the greatness of the consequence and that of the 
greatness of the consequent, moralists in desiring to compare 
them are much perplexed, as appears in the case of those who 
have treated of probability. The truth is that here as in 
other estimates disparate and heterogeneous and, so to speak, 
of more than one dimension, the greatness of that which is 
discussed is in reason composed of both estimates, and is like a 
rectangle, in which there are two considerations, viz. that of 
length and that of breadth ; and, as for the greatness of the 
consequence and the degrees of probability, we still lack that 
part of Logic which is to estimate them, 2 and the most of the 

1 Gerhardt reads: "exposer"; Erdmann and Jacques : "opposer." — Tr. 

2 I.e. the Calculus of Probabilities, the founder of which was Pascal, 
1623-1662, who developed the mathematical theory of probability in his cor- 
respondence with Fermat, 1601-1665, concerning certain questions on the 
equitable division of the stakes in games of chance proposed to Pascal by the 
Chevalier de Mere. Of. I. Todhunter, History of the Theory of Probability 
from the time of Pascal to that of Laplace, pp. 7-21, 8vo, Cambridge and 
London, 1865. Contributions were made to the theory by many of the dis- 
tinguished mathematicians of the period and after, including James Bernoulli, 
1651-1705; Huygens (vid. ante, p. 150, note 3); Demoivre, 1667-1754, in his 
Doctrine of chances, or method of calculating the probabilities of events at 
play, 3d ed., London, 1756; Laplace, 1749-1827, in his Thiorie analytique des 
probability (Vol. 7 of his (Euvres completes, publie'es sous les auspices de 
VAcademie des Sciences, seven vols., 4to Paris, 1878-1886), since which 
but little advance has been made in the theory; and Poisson, 1781-1840, in 
his Recherches sur la probability des jugements en matieres criminelles, etc., 
4to Paris, 1837. Leibnitz became acquainted with Pascal's labors during 
his residence in Paris, 1672-1676; cf. Guhrauer, Leibnitz. Leben, 1, 113 sq. 
He recognized the immense importance of this new "part of Logic," and 
thought to substitute it for the old and crude casuistry which had so long 
prevailed. In the letter to Bourguet, March 22, 1714, Gerhardt, 3; 570 ; Erd- 
mann, 723, Leibnitz glances briefly at the historical rise of the calculus of 
probabilities. For the philosophical side of the question, cf. J. S. Mill, Logic, 
Bk. III., chaps 18, 23, pp. 379 sq., 416 sq., 8th ed., Harper and Bros., New 



214 LEIBNITZ'S CRITIQUE OF LOCKE [uk. ii 

casuists who have written on probability have not even under- 
stood its nature, founding it with Aristotle, 1 upon authority, 
instead of founding it as they ought upon likelihood (vraisem- 
blance), authority being only one of the reasons which pro- 
duce likelihood.] 

§ 67. Ph. Here are some of the ordinary causes of this 
false judgment. First, ignorance, second, inattention, when a 
man does not reflect upon that of which he is aware. This 
is an affected and present ignorance which misleads the judg- 
ment as well as the will. 

Th. [It is always present, but not always affected ; for we 
do not always take it into our heads to think, when it is 
necessary, of what we know and the memory of which we 
should recall if we were master of it. Affected ignorance is 
always mixed with some attention at the time it is affected ; in 
the future, it is true, it may ordinarily include somewhat of in- 
attention. The art of thinking in time of need of what we know 
would be one of the most important if it were found ; but I 
do not see that men up to the present time have even thought 
of forming the elements of it, for the art of memory 2 of 
which so many authors have written is wholly another thing.] 

Ph. If then they bring together in confusion and hastily 
the reasons from one side and allow through neglect several 
sums which ought to enter into the reckoning to escape, this 

York, 1881; F. H. Bradley, The Principles of Logic, Bk. I., chap. 7, §§ 32 
sq., pp. 201 sq., Kegan Paul, Trench and Co., London, 1883; J. Venn, The 
Logic of Chance, 3d ed., Macmillan and Co., London, 1888; W. S. Jevons, The 
Principles of Science, 3d ed., Macmillan and Co., London, 1889. — Tr. 

1 For Aristotle's definition of probability, cf. Anal. Prior., II., 27, 70 a 3: 
"The probable is a generally admitted proposition. For what is known for 
the most part as thus happening or not happening, or being or not being, this 
is probable "; cf. also Wallace, Outlines, § 21, who quotes the Greek of the 
passage. Bhet. I., 2, 1357 a 34: " For the probable is that which for the most 
part happens." Aristotle accordingly rests much more upon experience 
than upon authority, and Leibnitz has not given his definition accurately. 
" The probable conclusion," says Schaarschmidt, is for Aristotle, "an incom- 
plete induction, whose problematic character he well understood, but did not 
determine more closely. Later Greek philosophers of a sceptical creed began 
to speak of grades of probability, but the moderns have been the first to 
fall upon the fruitful thoughts of a mathematical estimate of probability." 
— Tr. 

2 Mnemonics, the invention of which was ascribed to the poet Simonides, 
of Ceos, 556-469 B.C., perhaps because he was famous for the strength of his 
own memory. Cf. Cicero, he Oratore, Bk. II., chap. 82. — Tr. 



en. xxi] ON HUMAN UNDERSTANDING 215 

haste produces no less false judgments than if it were perfect 
ignorance. 

Th. [In reality many things must be taken into account, as 
should be the case, when the balance of reasons is discussed ; 
and the process is almost like that in the account-books of 
merchants. For no sum must be neglected, each must be 
properly estimated by itself, they must be properly arranged, 
and finally an exact collection must be made of them. But 
we neglect many weighty points either by its not occurring to 
us to think of them or by passing lightly over them ; and we 
do not give each its proper value, like the book-keeper, who 
was careful properly to calculate the columns of each page, 
but who calculated very badly the particular sums of each 
line or posting, before putting them in the columns ; this 
causes the examiners to be deceived, who look principally at 
what is in the columns. Finally, after having carefully noted 
all, they may be deceived in the collection of the sums of the 
columns and even of the final collection, in which is the sum 
of the sums. Thus we should still need the art of thinking 
and that of estimating probabilities, and besides the knowl- 
edge of the value of goods and evils in order properly to 
employ the art of consequences ; and furthermore, attention 
and patience would be necessary after all that, in order to 
push to the conclusion. Finally, a firm and constant resolu- 
tion to execute the conclusion arrived at is necessary ; and 
address, method, particular laws, and habits entirely formed 
in order to maintain the course in the future, when the con- 
siderations, which have caused it to be taken, are no longer 
present to the mind. Tt is true, thank God, that in what is of 
the greatest importance and which concerns the summam 
rerum, happiness and misery, there is no need of so much 
knowledge, aid, and address, as it would be necessary to have 
in order properly to judge in a council of state or of war, in 
a tribunal of justice, in a medical consultation, in some theo- 
logical or historical controversy, or in some point of mathe- 
matics or mechanics ; but as a recompense more firmness and 
habit is necessary, in what concerns this great point of fe- 
licity and virtue, in order always to adopt good resolutions 
and to follow them. In a word, for true happiness less 
knowledge suffices with more good will ; so that the greatest 



216 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

idiot may attain it as easily as the most learned and most skil- 
ful.] 

Ph. You see then that without liberty the understanding 
would be of no use, and that liberty without understanding 
would signify nothing. If a man could see what may do him 
good or evil without being able to move a step in advance 
towards the one or in removal from the other, would he be 
the better for the sight ? He would be indeed more miserable 
for this reason, for he would uselessly pine after the good and 
would fear the evil, that he sees is inevitable ; and he who is 
at liberty to run here and there in the midst of perfect dark- 
ness, in what respect is he better than if he were tossed about 
at the pleasure of the wind ? 

Th. [His caprice would be a little better satisfied, but he 
would be in no better condition to meet good or to shun evil.] 

§ 68. Ph. Another source of false judgment. Content with 
the first pleasure which comes to hand or which custom has 
rendered agreeable, we do not look farther. This then is 
also an occasion for men to judge wrongly when they do not 
regard as essential to their happiness that which really is so. 

Th. [It seems to me that this false judgment is comprised 
under the preceding kind where one is mistaken as to the 
consequences.] 

§ 69. Ph. The inquiry remains whether a man has the 
power to change the pleasure or displeasure which accom- 
panies any particular action. In many cases he can. Men 
may, and ought to, correct their palates and make them acquire 
a taste. They can change also the taste of the soul. A due 
consideration, practice, application, custom will bring about 
this result. Thus it is that men accustom themselves to 
tobacco, which usage or custom at last makes them find agree- 
able. It is the same as regards virtue. Habits have powerful 
charms and we cannot depart from them without uneasiness. 
You will, perhaps, regard it as a paradox that men can make 
things or actions more or less agreeable to themselves, so much 
do they neglect this duty. 

Th. [I have already made this statement above, § 37, 
towards the end, and § 47, also towards the end. We can 
make ourselves will anything and form our taste.] 

§ 70. Ph. Morality, established upon true foundations, can 



en. xxi] ON HUMAN UNDERSTANDING 217 



only determine to virtue : it suffices that infinite happiness 
and misery after this life are possible. We must admit that 
a good life, joined with the expectation of possible eternal 
felicity, is preferable to a bad life, accompanied by the fear of 
terrible misery, or, at least, of the terrible and uncertain hope 
of annihilation. All this is in the highest degree self-evident, 
although virtuous men should have only evil to endure in this 
world, and the wicked should taste therein perpetual pleas- 
ure, which is ordinarily quite otherwise. For rightly consid- 
ering all things, I believe they have the worst part even in 
this life. 

Th. [Thus were there no life beyond the grave an epicurean 
life would not be the most reasonable. And I rejoice, sir, that 
you rectify what you said to the contrary above, § 55.] 

Ph. Who could be so foolish, as to resolve (if he had his 
senses) to expose himself to a possible danger of being infin- 
itely unhappy so that he has nothing to gain therefrom for 
himself but pure annihilation ; instead of putting himself in 
the condition of the good man who has nothing to fear but 
annihilation, and who has eternal felicity to hope for ? I 
have forborne to speak of the certainty or probability of the 
future state, because I have no other design in this place than 
to show the false judgment of which each should acknowledge 
himself guilty on his own principles. 

Th. [The wicked are very prone to believe that the other 
life is impossible. But they have no reason for their belief 
other than that which compels them to limit themselves to 
what they learn by their senses, and that no one to their 
knowledge has come back from the other world. There was a 
time when upon the same principle we could reject the anti- 
podes, when we were unwilling to unite mathematics and the 
popular notions; and we could do so with as much reason "as 
we can now have in rejecting the other life, when we are 
unwilling to unite true metaphysics and the notions of the 
imagination. For there are three degrees of notions or ideas, 
viz. : popular, mathematical, metaphysical. The first do not 
suffice to make us believe in the antipodes ; the first and the 
second do not yet suffice to make us believe in the other 
world. It is true they furnish already favorable conjectures ; 
but if the second established certainly the antipodes before 



218 LEIBNITZ'S CKITIQUE OF LOCKE [bk. ii 

the experience we now have of it (I speak not of the inhabi- 
tants, but of the place at least which the knowledge of the 
roundness of the earth gave them among geographers and 
astronomers), the last give no less certitude of another life 
from this time, and before you have gone to see.] 

§ 72. Ph. Let us now return to power which is properly 
the subject of this chapter, liberty being only one form of it, 
but the most important. In order to have more distinct ideas 
of power, it will be neither beside the purpose nor useless to 
obtain a more exact knowledge of what is called action. I 
said at the beginning of our discourse on power that there 
are two kinds of actions, of which we have some idea, viz. : 
motion and thought. 1 

Th. [I thought you could avail yourself of a more general 
term than that of thought, viz. : that of 'perception, attributing 
thought only to minds, while perception belongs to all the 
entelechies. But I do not wish, however, to contest with any 
one the liberty to take the term thought in the same general 
way. And for myself indeed I shall perhaps do so some time 
without being aware of it.] 

Ph. Now, although we give to those two things the name of 
action, we shall find however that it does not always suit them 
perfectly, and that there are some examples which we shall 
recognize rather as passions. For in these examples sub- 
stance, in which we find movement or thought, receives purely 
from without the impression through which action is com- 
municated to it, and acts only by the sole capacity it has 
of receiving this impression, which is only a passive power. 
Sometimes substance or the agent puts itself in action by its 
own power, and it is there properly an active power. 

Th. I have already said that, taking action in metaphysical 
strictness as that which takes place in substance spontaneously 
and from its own depths, that alone is, properly speaking, a 
substance which is active, 2 for all arises for it from itself after 
God ; it being impossible for one created substance to have 

1 Locke has: "thinking," Philos. Works, Vol.1, p.413 (Bohn'sed.).— Tr. 

2 Cf. Be ipsa natura, etc., 1698, § 9 ad Jin.; Gerhardt, 4, 509; Erdmann, 
157 ; Jacques, 1, 461 (in French) ; J. H. v. Kirchmann, Die klein. philos. 
wicht. Schrift. v. G. W. Leibniz (Philos. Bibliothek, Bd. 81), p. 121 (in Ger- 
man) , Erick Koschny, Leipzig, 1879 ; also Kuno Fischer, Gesch. d. neuern Philos., 
Vol. 2 (G. W. Leibniz), p. 334, 3d ed., Heidelberg: C. Winter, 1889. —Tr. 



ch. xxi] ON HUMAN UNDERSTANDING 219 

influence upon another. But taking action as an exercise of 
perception and passion as its contrary, there is action in true 
substance only when their perception (for I grant it to all) is 
developed and becomes more distinct, as there is passion only 
when it becomes more confused ; so that in substances capable 
of pleasure and of pain, all action is a step towards pleasure 
and all passion a step towards pain. As for motion, it is 
only a real phenomenon, because matter and mass to which 
motion belongs is not properly speaking a substance. But 
there is an image of action in motion as there is an image of 
substance in mass ; and in this respect we can say that the 
body acts (agit) when there is spontaneity in its change and 
that it is passive (patit) when it is urged on or hindered by 
another ; as in the veritable action or passion of a veritable 
substance we may take as its action, and attribute to itself, 
the change by which it tends to its perfection. And in the 
same manner we can take as passion and attribute to a 
foreign cause the change by which the contrary happens to it ; 
although this cause is not immediate, because, in the first case, 
the substance itself, and in the second the foreign things serve 
to explain this change in an intelligible way. I allow bodies 
only an image of substance and action, because that which is 
composed of parts cannot pass, to speak accurately, as one 
substance, any more than a flock ; but we can say that there 
is therein something substantial, of which the unity, that 
which makes it as it were one being, comes from thought.] 

Ph. I have thought that the power to receive ideas or 
thoughts by the operation of some foreign substance was 
called power of thought, although at bottom it is only a pas- 
sive power or a simple capacity making abstraction from the 
reflections and internal changes which always accompany the 
received image, for the expression, 1 which is in the soul is, as 
it should be, that of a living mirror ; but the power which we 
have of recalling absent ideas at our choice, and of comparing 
together those that we think to the purpose, is truly an active 
power. 

Th. [This also agrees with the notions I have just pre- 
sented, for there is in this a passage to a more perfect state. 

1 Gerhardt and Erdrnann read: " 1' expression " ; Jacques: " l'impres- 
sion." — Tr. 



220 LEIBNITZ'S CRITIQUE OF LOCKE [me n 

But I should suppose that there is also action in sensations so 
far as they give us more distinct perceptions and consequently 
the opportunity of making remarks and so to speak of devel- 
oping ourselves.] 

§ 73. Ph. Now I think it appears that we can reduce the 
primitive and original ideas to this small number : extension, 
solidity, mobility (i.e. passive power, or rather capacity of 
being moved), which come to us in the mind by way of reflec- 
tion, and finally, existence, duration, and number, which come 
to us by the two ways of sensation and reflection ; for by 
these ideas we could explain, if I am not mistaken, the nature 
of colors, sounds, tastes, odors, and all the other ideas we 
have, if our faculties were subtile enough to perceive the dif- 
ferent motions of the minute bodies which produce these sen- 
sations. 

Th. To speak the truth, I believe that these ideas, which 
you here call original and primitive, are for the most part not 
wholly so, being susceptible in my view of further resolution ; 
but I do not blame you at all, sir, for having limited yourself 
and for not having pushed the analysis farther. Moreover, 1 1 
believe that if their number can be diminished by this means, 
it can be increased by adding other ideas more original or as 
much so. " As to the question concerning their arrangement, I 
should consider, following the order of the analysis, exist- 
ence anterior to the others, number to extension, duration to 
motivity or mobility ; although this analytic order is not 
ordinarily that of the occasions which make us think of them. 
The senses furnish us the material for reflection and we should 
not even think of thought, if we did not think of something 
else, i.e. of the particular things which the senses furnish. 
And I am persuaded that created souls and minds are never 
without organs and never without sensations, as they cannot 
reason without characters. Those who have desired to main- 
tain a complete separation and mode of thinking in the sepa- 
rated soul, inexplicable by all that we know, and separated 

1 Gerhardt reads: "D'ailleurs je crois que si le nombre en pourroit estre 
diminue par ce moyen, il pourroit estre augmente," etc. ; Erdmann and Jacques 
read : " D'ailleurs si c'est vrai, que le nombre en pourroit etre diminue par ce 
moyen, je crois qn'il pourroit etre augumente en y ajoutant d'autres Idees 
plus originales ou autant." — Tr. 



ch. xxn] ON HUMAN UNDERSTANDING 221 

not only from our present experiences, but, what is much 
more, from the general order of things, have given too much 
influence to so-called strong minds, and have made the finest 
and the grandest truths objects of suspicion to many people, 
having indeed deprived themselves thereby of some excellent 
means of proving them, which this order furnishes us.] 



CHAPTER XXII 

OF MIXED MODES 

§ 1. Ph. Pass we on to the mixed modes. I distinguish 
them from the more simple modes, which are composed only of 
simple ideas of the same kind. Moreover, the mixed modes 
are certain combinations of simple ideas which are not re- 
garded as characteristic marks of any real being, which has a 
fixed existence, but as scattered and independent ideas which 
the mind joins together; and they are thereby distinguished 
from the complex ideas of substances. 

Th. [Properly to understand these we must recall our for- 
mer divisions. According to you ideas are simple or complex. 
The complex are either substances, modes, or relations. Modes 
are either simple (composed of simple ideas of the same kind) 
or mixed. Thus, in your view, there are simple ideas, ideas 
of modes, both simple and mixed, ideas of substances and 
ideas of relations. We could, perhaps, divide the terms or 
the objects of ideas into abstract and concrete ; the abstract 
into absolute and into those which express relations ; the 
absolute into attributes and into modifications ; both into 
simple and composite ; the concrete into substances and into 
substantial things, made up of or the resultants of true and 
simple substances.] 

§ 2. Ph. The mind is purely passive, respecting its simple 
ideas, which it receives as sensation and reflection present 
them to it. But it often acts by itself, indeed, in reference 
to the mixed modes, for it can combine the simple ideas in 
making complex ideas without considering whether they so 
exist united in nature. This is why we give to these kinds of 
ideas the name of notion. 



222 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

Th. [But reflection which makes us think of simple ideas 
is often voluntary also, and, moreover, the combinations, which 
nature has not made, can produce themselves in us, as it were 
in dreams and reveries by means of memory alone, without 
the mind's acting more than in the simple ideas. As for the 
term notion, many apply it to all sorts of ideas or conceptions, 
to the original as well as to the derived.] 

§ 4. Ph. The mark of several ideas combined in one alone 
is the name. 

Th. [That means, if they can be combined, in which respect 
they are often lacking.] 

Ph. The crime of killing an old man, not having a name 
like parricide, is not at first regarded as a complex idea. 

Th. [The reason why the murder of an old man has no name 
is that, the laws not having attached thereto a particular pun- 
ishment, this name would be useless ; but ideas do not depend 
on names. An ethical author who should invent one for the 
crime and treat in a special chapter of Gerontophony, showing 
what is due to old men and how it is a barbarous act not to 
spare them, would not on that account present us with a new 
idea.] 

§ 6. Ph. It is always true that the manners and usages 
of a nation, making combinations familiar to it, cause each 
language to have particular terms, which cannot always be 
translated word for word. Thus ostracism among the Greeks 
and proscriptio among the Romans were words which other 
languages cannot express by equivalent words. Therefore, 
change of customs makes also new words. 

Th. [Chance also plays its part, for the Trench do not use 
horses as much as other neighboring peoples ; but having 
abandoned their old word, which corresponded to the cavalcar 
of the Italians, they are forced to say by paraphrase : oiler a 
cheval — to go on horse-back.] 

§ 9. Ph. We acquire ideas of mixed modes by observation, 
as when we see two men wrestling ; we acquire them also by 
invention (or a voluntary union of simple ideas), thus, he who 
invented printing had the idea of it before this art existed. 
We acquire them finally by explaining terms, affecting actions 
which we have never seen. 

Th. [We can further acquire them while dreaming or in a 



ch. xxn] ON HUMAN UNDERSTANDING 223 

state of revery without the combinations being voluntary, for 
example, when we see in a dream a golden palace without 
having thought of it before.] 

§ 10. Ph. The simple ideas which have been most modified 
are those of thought, motion, and power, whence actions are 
conceived to flow; for the great business of mankind consists 
in action ; all actions are thoughts or motions. The power or 
aptitude to do anything which is found in man constitutes 
the idea which we call habit, when this power has been 
acquired by often doing the same thing; and when we can 
force it to action upon each occasion that presents itself, we 
call it disposition. Thus, tenderness is a disposition to friend- 
ship or love. 

Th. [By tenderness you understand here, I presume, the 
tender heart, but elsewhere you seem to me to regard tender- 
ness as a quality which one has, as a lover, which renders him 
very sensible to the good and evil of the object loved. This it 
is to which it seems to me the chart of affection is moving in 
the excellent romance Clelie. 1 And, as charitable persons love 
their neighbor with some degree of tenderness, they are sensi- 
ble to the good and evil of another, and generally those who 
have the tender heart have some disposition to love with ten- 
derness.] 

Ph. Boldness is the power to do or say before others what 
you wish without being put out of countenance, a self-confi- 
dence, which, in relation to this last part which concerns dis- 
course, had a particular name among the Greeks. 

Th. [It would be well to seek a word for this notion, which 
is here attributed to that of boldness, but which is often em- 
ployed wholly otherwise, as when we say Charles the Bold. 
Not to be put out of countenance is a strength of mind, but 
one which bad men abuse when they have become impudent ; 
as shame is a weakness, but excusable and even praiseworthy 
in certain circumstances. As for parrhesia, 2 which you per- 
haps understand by the Greek word, it is still attributed to 
writers who speak the truth without fear, although, then not 

1 CMlie, Histoire Romaine, a romance by Mile. Scudery, 1607-1701. The 
scene is laid early in Roman history ; the heroine is Cloelia, who escaped from 
Porsena by swimming the Tiber. — Tr. 

2 wapprjcria. — Tr. 



224 LEIBNITZ'S CRITIQUE OE LOCKE [bk. 11 

speaking in the presence of people, they are not liable to be 
discountenanced. ] 

§ 11. Ph. As power is the^ource whence proceed all actions, 
the name of cause is given to the substances in which these 
powers reside, when they reduce their power to act; and they 
call effects the substances produced by this means, or rather 
the simple ideas (i.e. the objects of simple ideas), which, by 
the exercise of power are introduced into a subject. Thus the 
efficacy by which a new substance or idea (quality) is pro- 
duced, is called action in the subject exercising this power and 
passion in the subject in which some simple idea (quality) is 
altered or produced. 

Th. [If power is taken as the source of action, it means 
something more than an aptitude or facility, by which power 
was explained in the preceding chapter ; for it includes, be- 
sides, tendency as I have already more than once remarked. 
This is why' in this sense I have been wont to appropriate to 
it the term entelechy, which is either primitive and answers to 
the soul taken as an abstract thing, or derivative as it is con- 
ceived in conation (le conatus) and in vigor and impetuosity. 
The term cause is here understood only as efficient cause ; but 
it is also understood as final or the motive, not to speak here 
of matter and form which are also called causes in the schools. 
I do not know whether we can say that the same being is 
called action in the agent and passion in the patient, and is 
thus found in two subjects at once like relation, and, whether 
it is not better to say that there are two beings, one in the 
agent, the other in the patient.] 

Ph. Many words which seem to express some action signify 
only the cause and the effect ; as creation and annihilation 
contain no idea of action or of the manner, but simply of the 
cause and the thing which is produced. 

Th. [I admit that in thinking of creation, we do not con- 
ceive a mode of acting, capable of any detail, which cannot 
indeed there be expedient; but, since we express something 
besides God and the world, for we think that God is the cause 
and the world the effect, or else that God has produced the 
world, it is manifest that we think still of action.] 1 

1 Leibnitz regards the concept of creation in the sense of the origination of 
substances as incapable of further explanation because we can form no idea 



ch.xxiii] ON HUMAN UNDERSTANDING 225 

CHAPTER XXIII 

OF OUR COMPLEX IDEAS OF SUBSTANCES 

§ 1. Ph. The mind notices that a certain number of simple 
ideas constantly go together, which, presumed to belong to one 
thing only, are called by one name when thus united in one 
subject. Whence it comes that, although this is in truth a 
mass of many ideas joined together, we are afterwards led by 
inadvertence to speak of them as a single, simple idea. 

Th. [I see nothing in the accepted expressions which de- 
serves to be taxed with inadvertence; and although we recog- 
nize only one subject and one idea, we do not recognize only 
one simple idea.] 

Ph. Not being able to imagine how these simple ideas can 
subsist by themselves, we are accustomed to assume something 
which sustains them {substratum), in which they subsist or 
whence they result, to which for this effect we give the name 
of substance.'] 

Th. 1 [I believe that there is reason in thus thinking, and 
we have only to accustom ourselves to it or to assume it, since, 
at first, we conceive several predicates in one and the same 
subject, and these metaphorical words, support (soutien) or sub- 
stratum mean only this ; so that I do not see why it should 
cause any difficulty. On the contrary, it is rather the concretum, 
as wise, warm, shining, which arises in our mind, than the 
abstractions or qualities (for these and not the ideas are in 
the substantial object), as knowledge, heat, light, etc., which 
are much more difficult to comprehend. We may even doubt 
whether these accidents are veritable existences, as in fact 
they are very often only relations. We know also that it is 
these abstractions which cause the greatest difficulties to 
spring up when we wish to examine them minutely, as those 

of the process. For some other expressions concerning it, cf. La Monaclo- 
logie, § 47, Gerhardt, 6, 614; Erdmann, 708, b. ; Letter to Bayle, Gerhardt, 3, 
58; Erdmann, 191. Gerhardt, 3, 61, and note, says the original is without 
date; Erdmann gives it 1702. Of. also Dillmann, Eine neue Darstg. d. Leib- 
niz. Monadenlehre, p. 451 sq. — Tk. 

1 Erdmann has " Ph.," a typographical error. — Tk. 
Q 



220 LEIBNITZ'S CRITIQUE OF LOCKE [inc. ii 

know who are familiar with the subtilties of the scholastics, 
the most intricate of which falls at once if we will banish 
abstract existence and resolve to speak ordinarily only by 
concretes and admit no other terms in scientific demonstra- 
tions but those which represent substantial subjects. Thus it 
is nodum quaerere in scirpo, 1 if I may so speak, and reversing 
things to take the qualities or other abstract terms as the 
easier and the concrete as something very difficult.] 

§ 2. Ph. We have no other notion at all of pure substance 
in general, than of an indescribable subject, which is to us 
altogether unknown and which is supposed to be the support 
of qualities. We speak like children to one who has no 
sooner asked them what a certain thing unknown to them is, 
than they make this reply very satisfactory to their taste that 
it is something, but, which employed in this way, means that 
they do not know what it is. 

Th. [In distinguishing two things in substance, the attri- 
butes or predicates, and the common subject of these predi- 
cates, it is no wonder that we can conceive nothing particular 
in this subject. It must be so, indeed, since we have already 
separated from it all the attributes in which we could conceive 
any detail. Thus to demand something more in this pure subject 
in general than what is necessary in order to conceive that it 
is the same thing (for example, which understands and wills, 
which imagines and reasons), is to demand the impossible, 
and to act contrary to our own supposition, which has been 
made in making abstraction and conceiving separately the 
subject and its qualities or accidents. We could apply the 
same pretended difficulty to the notion of being and to all that 
is clearer and more primitive ; for we could demand of the 
philosophers what they conceive when conceiving pure being 
in general ; for all detail being excluded by that means there 
will also be little to say, when we are asked what is pure sub- 
stance in general. Thus I believe that the philosophers do 
not deserve to be laughed at, as is here done, in comparing 
them with an Indian philosopher, who, being asked upon what 
the earth rested, replied, upon a great elephant ; and then 
when asked what sustained the elephant, replied, a great tor- 

1 To seek a knot in a bulrush, to find a difficulty when there is none. Cf. 
Plaut. Men. 2, 1, 22 ; Ter. And. 5, 4, 38. — Tr. 



ch. xxiii] ON HUMAN UNDERSTANDING 227 

toise; and, at last, when pressed to say upon what the tortoise 
rested, was compelled to say something, I know not ivhat. But 
this consideration of substance, 1 entirely slender as it appears, 
is not so empty and sterile as you think. It gives rise to 
many consequences of greatest importance in philosophy, and 
which are capable of giving it a new aspect.] 

§ 4. Ph. We have no clear idea of substance in general, and 
§ 5, we have as clear an idea of mind as of body ; for the 
idea of corporeal substance in matter is as far from our con- 
ceptions as that of spiritual substance. It is almost as the 
promoter said to this young doctor of law, who cried to him 
in the solemnity, to say utriusque : You are right, sir, for you 
know as much in the one case as the other. 

Th. [As for myself, I believe that this opinion of our igno- 
rance arises from that which demands a kind of knowledge of 
which the object does not admit. The true mark of a clear 
and distinct notion of an object is the means we have of 
knowing therein many truths by a priori 2 proofs, as I have 
shown in a discourse on truths and ideas, 3 published in the 
" Actes de Leipzig " of the year 1684. 

§ 12. Ph. If our senses were sufficiently penetrating, the 
sensible qualities, for example, the yellow color of gold, would 
disappear, and instead of that we should see a certain admir- 
able contexture of parts. This appears evident by means of 
microscopes. This present knowledge is suitable to the state 
in which we find ourselves. A perfect knowledge of things 

1 In Leibnitz's philosophy substance is a unitary, individual, spontane- 
ously active being, as opposed to the " empty and sterile " conception of Aris- 
totelian scholasticism ; cf. ante, p. 154 and note. Locke's criticism concerns 
the scholastic conception only. — Tr. 

2 Cf. New Essays, Bk. IV., chap. 17, § 1, Th.; Theodicee, I., § 44, Gerhardt, 
6, 127; Erdmanu, 515, b. For a brief critical history of the concepts of the 
a priori and the a posteriori, cf. Rudolph Eucken, The Fundamental Concepts 
of Modem Philosophic Thought, pp. 81-91, D. Appleton and Co., New York, 
1880 ; and for Leibnitz's use of the terms, op. cit., p. 82, with the note contain- 
ing references to the places where a priori occurs in Erdmann's and Foucher 
de CareiPs editions of his works. — Tr. 

3 Meditationes de Cognitione, Veritate et Ideis, in the " Acta Eruditorum," 
Nov., 1684. Gerhardt, 4, 422 sq. ; Errlmann, 79 sq. The passage referred to 
is found in Gerhardt, 425 ; Erdmann, 80 b. ; translation, Duncan, Philos. Works 
of Leibnitz, 30. The piece has been translated into German, with notes, by 
J. H. v. Kirchmann in his Philos. Bibliothek, Bd. 81, Die klein. philos. ivicht. 
Schriften v. G. W. Leibniz ; Bd. 82, Erlauterungen. — Tr. 



228 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

which surround us, is, perhaps, beyond the capacity of every 
finite being. Our faculties suffice to make us know the Crea- 
tor, and to instruct us as to our duties. Should our senses 
become more acute, such change would be incompatible with 
our nature. 

Th. [All that is true; and I have said something to the 
same effect above. But the color yellow does not cease to 
be a reality like the rainbow, and we are apparently destined 
to a state far beyond the present, and can even go on to the 
infinite, for there are no elements in the corporeal nature. If 
there were atoms, as the author appeared to believe in another 
place, perfect knowledge of the body could not be beyond 
every finite being. For the rest, if some colors or qualities 
should disappear from our eyes better armed or become more 
penetrating, others would apparently spring into being, and 
it would require a new growth of our perspicacity to make 
these also disappear, and this could go on to infinity, as the 
actual division of matter effectively proceeds.] 

§ 13. Ph. I do not know but that one of the great advan- 
tages which some spirits have over us consists in the fact that 
they can assume to themselves organs of sensation which are 
precisely suited to their present design. 

Th. [We do this indeed in making for ourselves micro- 
scopes ; but other creatures can go much farther. And, if we 
could transform our eyes themselves, which we do effectively 
to some extent according as we wish to see near at hand or at 
a distance, we should be obliged to have something 1 belonging 
more exclusively to us than they in order to shape them by 
its means, for it is necessary, at least, that all be done mechan- 
ically, because the mind cannot operate immediately upon the 
body. For the rest, I am also of the opinion that genii per- 
ceive things in a manner which is somewhat related to ours, 
even if they should have the agreeable advantage which the 
imaginative Cyrano 2 attributes to some animated natures in 

1 I.e. the soul to make use of the capacity of the eyes for accommodation. 
— Tr. 

2 Cyrano de Bergerac, c. 1620 — 1655, in his philosophical romance, Ilistoire 
comique des etats et empires du soleil. He was author also of the Histoire 
comique des etats et empires de la hme, or, as the title is sometimes given, 
Voyage dans la lune. — Tr. 



ch. xxm] ON HUMAN UNDERSTANDING 229 

the sun, composed of an infinite number of little winged crea- 
tures, which, by transporting themselves according to the 
command of the ruling soul, form all kinds of bodies. There 
is nothing so marvellous that the mechanism of nature cannot 
produce it ; and I believe that the learned fathers of the 
Church were right in attributing bodies to the angels. 1 ] 

§ 15. Ph. The ideas of thinking and of moving a body, 
which we find in that of the mind, can be conceived as clearly 
and distinctly as those of extension, solidity, and mobility, 
which we find in matter. 

Th. [As regards the idea of thought I agree. But I am 
not of this opinion as regards the idea of moving bodies, for, 
according to my system of Pre-established Harmony, bodies 
are so made that being once put in motion, they continue 
therein, according as the actions of the mind require. This 
hypothesis is intelligible ; the other is not.] 

Ph. Each act of sensation gives us an equal view of things 
corporeal and spiritual ; for while sight and hearing give me 
the knowledge that there is some corporeal being without me, 
I ' know in a way still more certain that there is within me a 
spiritual being which sees and hears. 

Th. [It is very well said and very true that the existence 
of the spirit is more certain than that of sensible objects. 2 ] 

§ 19. Ph. Spirits as well as bodies can operate only where 
they are and in different times and places ; thus I can only 
attribute change of place to all finite spirits. 

Th. [I believe that is reasonable, place being only an order 
of coexistences.] 

Ph. It is only necessary to reflect upon the separation of 
the soul and the body by death to be convinced of the move- 
ment of the soul. 

Th. [The soul might cease to operate in this visible body ; 
and if it could cease thinking all at once, as the author has 
maintained above, it might be separated from the body with- 
out being united to another; thus its separation would be 
without movement. But for myself, I believe that it thinks 

1 Cf. Letters to Des Bosses, Sept. 20, Oct. 4, 1706, Gerhardt, 2, 316, 319; 
Erdmann, 439. Also Descartes' letters, passim. — Tr. 

2 Cf. Descartes, Meditations, especially II. and VI. Veitch's translation, 
8th ed., pp. 104 sq., 151 sq. — Tr. 



230 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

and feels always, that it is always united to some body, and, 
indeed, that it never leaves entirely and all at once the body 
to which it is united.] 

§ 21. Ph. If anyone says that spirits are not in loco sed in 
aliquo ubi I do not suppose that now we would rely much 
upon this method of speaking. But if anyone thinks that 
it can receive a reasonable sense, I pray him to express it in 
language generally intelligible, and to draw therefrom after- 
wards a reason showing that spirits are not capable of motion. 

Th. [The schools have three kinds of Ubeity, or modes of 
existing somewhere. The first is called circumscriptive, which 
they attribute to bodies in space which are there punctatim, in 
such wise that they are measures according to which we can 
assign the points of the thing placed corresponding to the 
points of space. The second is the definitive, when we can 
define, i.e. determine, that the situated thing is in such a space, 
without being able to assign the precise points or the peculiar 
places exclusive of what is there. Thus it has been con- 
sidered that the soul is in the body, not supposing it possible 
to assign a precise point at which the soul or some portion of 
the soul is, without its being also at some other point. More- 
over, many learned men have thus viewed the matter. It is 
true that Descartes desired to place narrower limits to the 
soul by locating it properly in the pineal gland. 1 Neverthe- 
less he did not dare to say that it is exclusively at a certain 
point in this gland ; and this not being so he gains nothing, 
and it is in this respect precisely as if he gave it the entire 
body as its prison or place. I believe that nearly the same 
statement as that made regarding souls, must be made in 
respect to the angels, whom the great doctor, a native of 
Aquino, believed to be in a place only by operation 2 which in 
my view is not immediate and reduces itself to pre-established 
harmony. The third ubeity is the repletive, which is attrib- 
uted to God, who fills all the universe in a still more eminent 
degree than the disembodied spirits, for he works immediately 

1 Cf. Descartes, Dioptrica, IV., 1 sq. ; Passiones Animas, I., 31 sq.; also 
Prin. Philos., IV., 189, 196, 197, although here the point of contact in the 
hrain of the soul and body is not designated by name. — Tr. 

2 Cf. Thomas Aquinas, 1225 or 1227-1274, Summct Theologica, Pt. I. Quest. 
52, Article, 2; also Quest. 53. — Tr. 



ch. xxm] ON HUMAN UNDERSTANDING 231 

upon all creatures by continually producing them, while finite 
spirits cannot exercise any immediate influence or operation. 
I do not know whether this doctrine of the schools deserves 
to be ridiculed, as it seems some try to do. But we can 
always attribute a kind of movement to souls at least in rela- 
tion to the bodies with which they are united, or in relation 
to their mode of perception.] 

§ 23. Ph. If any one says he knows not how he thinks, I 
reply that he knows no more how the solid particles of the 
body are united to make an extended whole. 

Th. [It is difficult enough to explain cohesion; but this 
cohesion of parts does not appear necessary to make an 
extended whole, since we can say that matter perfectly subtile 
and fluid constitutes an extension, without the particles being 
united the one to the other. But, to speak the truth, I 
believe that perfect fluidity belongs only to the primary 
matter, 1 i.e. matter in the abstract, and, as an original quality, 
just as repose ; but not to secondary matter, such as is 
actually found, invested with its derivative qualities ; for, I 
believe that there is no mass, which is of the utmost subtil- 
ity; and that there is more or less connection everywhere, 
which arises from movements so far as they are conspirant 
and would be disturbed by separation, which cannot take 
place without some violence and resistance. For the rest, the 
nature of perception and thus of thought furnishes a notion 
of the most original conditions. I believe, further, that the 
doctrine of substantial unities or monads will throw much 
light upon it.] 

Ph. As for cohesion, many explain it by means of the sur- 
faces by which two bodies touch, which an ambient fluid 2 (for 
example, the air) presses one against another. It is very 
true that the pressure § 24 of an ambient fluid can hinder the 
avulsion of two polished surfaces from one another in a line 
perpendicular to them ; but it cannot hinder them from separat- 
ing by a movement parallel to these surfaces. This is why, 
if there were no other cause of the cohesion of bodies, it 
would be easy to separate all their parts, by making them thus 

i Cf. ante, p. 131 and note. — Te. 

2 Locke's term, Philos. Works, Vol. 1, p. 438, § 21 (Bonn's ed.). — Tr. 



232 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

slide laterally, taking therefor any plane yon wish which 
intersects any mass of matter. 

Th. [Yes, no doubt if all the smooth particles applied to 
each other were in one and the same plane or in parallel 
planes; but that not being so nor capable of so being, it is 
manifest that in trying to make the one slide, you will act 
altogether differently upon an infinite number of others, whose 
plane will make an angle with the first ; for you must know 
that it is difficult to separate two congruent surfaces, not only 
when the direction of the movement of separation is perpen- 
dicular, but further when it is oblique to the surfaces. Thus 
it may be conceived that there are leaves applied to one 
another in every direction in the polyhedral bodies that nature 
forms in ores and elsewhere. But I admit that the pressure 
of the ambient fluid upon smooth surfaces applied to each 
other does not suffice to explain the basis of all cohesion, for 
it is tacitly assumed that the tables applied the one against 
the other already have cohesion.] 

§ 27. Ph. I have always supposed that the extension of a 
body was something else than the cohesion of solid particles. 

Th. [That does not appear to me to agree with your own 
preceding explanations. It seems to me that a body in which 
there are internal movements or whose particles are in the act 
of detaching themselves one from another (as I believe hap- 
pens always) cannot be extended. Thus the notion of exten- 
sion appears to me wholly different from that of cohesion.] 

§ 28. Ph. Another idea we have of body is the power of 
communicating motion by impulse; and another we have of the 
soul is the power of producing motion by thought. Experience 
clearly furnishes us each day these two ideas ; but if we wish 
to investigate further how this is done, we find ourselves 
equally in the dark. For, as regards the communication of 
motion, wherein one body loses as much motion as another 
receives, which is the most ordinary case, we conceive there 
nothing else than a motion which passes from one body into 
another; which is, I think, as obscure and as inconceivable 
as the manner in which our mind moves or stops our bodies by 
thought. It is still more difficult to explain the increase of 
motion by means of impulse, which is observed or believed to 
happen in certain cases. 



ch. xxm] ON HUMAN UNDEKSTANDING 233 

Th. [I am not astonished that yon find insurmountable dif- 
ficulties where you seem to assume a thing so inconceivable 
as the passage of an accident from one subject to another ; 
but I see nothing which compels us to an assumption which is 
no less strange than that of the scholastics of accidents with- 
out a subject, which they have taken care however to attribute 
only to the miraculous action of the divine omnipotence, 
while here this passage would be merely an ordinary one. I 
have already said something about it above (chap. 21, § 4 1 ), 
where I also remarked that it is not true that a body loses as 
much motion as it gives to another ; which they seem to conceive 
as if motion were a substantial thing and resembled salt dissolved 
in water, which comparison is actually the one M. Eohaut, 2 if 
I mistake not, has used. I add here that this is not even the 
most usual case, for I have elsewhere demonstrated that the 
same quantity of motion is maintained only when the two 
bodies which come into collision proceed in one and the same 
direction before the collision and still proceed in one and the 
same direction after the collision. It is true that the veritable 
laws of motion are derived from a cause superior to matter. 
As for the power of producing motion by thought, I do not think 
we have any idea of it, as we have no experience of it. The 
Cartesians themselves admit that souls cannot give a new 
force to matter, but they pretend that they give it a new 
determination or direction of the force it has already. For 
myself, I maintain that souls change nothing in the force nor 
in the direction of bodies ; that the one would be as incon- 
ceivable and unreasonable as the other, and that you must 
avail yourself of the pre-established harmony in order to 
explain the union of the soul and the body.] 

Ph. It is worth our consideration whether active power is 
not the proper attribute of spirits and passive power of 
bodies ? Whence we might conjecture that created spirits, 

1 Cf. ante, p. 176. — Te. 

2 James Eohaut or Rohault, 1620-1675, a French physicist, a follower of 
Descartes. His chief work, the Physics, was written in French, and trans- 
lated into Latin, with valuable notes, by Dr. Samuel Clarke, 1675-1729, and 
into English by his brother Dr. John Clarke. It was a text-book in the Uni- 
versity of Cambridge, until supplanted by the treatises of Sir Isaac Newton. 
The original work first appeared in 1671, and enlarged, in two vols., in 1682. 
Clarke's Latin version, 8vo., in 1697 ; the 4th and best edition, Jacobi Rohaulti 
Physica, 8vo., 1718.— Tr. 



234 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

being active and passive, are not totally separate from simply 
passive matter ; and that these other beings, which are active 
and passive at the same time, partake of both. 

Th. [These thoughts greatly please me and entirely express 
my conviction, provided you explain the word spirit so gener- 
ally that it comprises all souls, or rather (to speak still more 
generally) all the entelechies or substantial unities, which are 
analogous to spirits.] 

§ 31. Ph. I much wish that you would show me in the 
notion we have of spirit anything more confused 1 or nearer a 
contradiction than what the very notion of body includes. I 
mean infinite divisibility. 

Th. [What you here say further in order to make evident 
that we understand the nature of the spirit as well or better 
than that of the body is very true ; and Fromondus, 2 who has 
published a book, De compositione continui, was right in enti- 
tling it Labyrinth. But the question arises from a false idea 
you have of the nature of body as well as of space.] 

§ 33. Ph. The idea of God indeed comes to us as others 
do, the complex idea of God we have being composed of the 
simple ideas which we receive from reflection and which we 
extend by the idea we have of the infinite. 

Th. [Upon that question I refer to what I have already 
said in several places in order to make evident that all these 
ideas, and particularly that of G-od, are in us originally, and 
that we only make ourselves take notice of them, and that 
above all, the idea of the infinite is not formed by an extension 
of finite ideas. 3 ] 

§ 37. Ph. The majority of the simple ideas which compose 
our complex ideas of substances are, properly considered, only 
powers, whatever our inclination to take them as positive quali- 
ties. 

1 Locke's word is "perplexed," Philos. Works, Vol. 1, p. 443 (Bohn's ed.). 
— Tr. 

2 Libert Froidmont or Fromont — Latin, Fromondus — 1587-1653, a Flemish 
theologian, Professor of Philosophy and Theology in the University of Lou- 
vain. His theological, philological, and scientific knowledge was very exten- 
sive. Descartes esteemed highly both his knowledge and his person. Cf. 
Descartes' letters. His book, Labyrinthus sive de compositione continui, ap- 
peared at Antwerp in 1631. — Tr. 

3 Cf.ante, pp. 16, 17; New Essays, Book II., chap. 14, § 27, Th., and note 1, 
ante, p. 158; chap. 17, § 1, Th., ante, p. 162. — Tr. 



ch. xxv] ON HUMAN UNDERSTANDING 235 

Th. [I think that the powers, which are not essential to 
substance and which include not only an aptitude, but also a 
certain tendency, are properly what is or ought to be under- 
stood by real qualities.] 



CHAPTER XXIV 

OF COLLECTIVE IDEAS OF SUBSTANCES 

§ 1. Ph. After simple substances we come to the aggregates. 
Is it not true that the idea of this mass of men composing an 
army, is as much a single idea as that of one man? 

Th. [You are right in saying that this aggregate (ens per 
aggregationem, to use the language of the school), makes one 
single idea, although, properly speaking, this mass of sub- 
stances does not form in truth one substance. This is a result 
to which the soul by its perception and its thought gives its 
last achievement of unity. You may, however, say in a sense 
that it is something substantial, i.e. comprising substances.] 



CHAPTER XXV 

OF RELATION 

§ 1. Ph. It remains to consider the ideas of relations which 
are the poorest in reality. When the mind regards one thing 
in comparison with another, this is a relation or respect, 1 and 
the denominations or relative terms, which are produced, are 
like so many marks which serve to lead our thoughts beyond 
the subject to something distinct from it, and these two are 
called subjects of the relation (relata). 

Th. [Relations and orders have something of the essence of 
reason, although they have their foundation in things ; for Ave 
can say that their reality, like that of eternal truths and possi- 
bilities, comes from the supreme reason.] 

§ 5. Ph. There may, however, be a change of relation with- 
out any change happening in the subject. Titius, whom to- 
i Locke's word, Philos. Works, Vol. 1, p. 449 (Bohn's ed.).— Tr. 



236 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

day I consider as a father, ceases to be such to-morrow without 
any change being made in himself, by the sole fact of his 
son's death. 

Th. [That statement may very well be made in view of 
things which are perceived ; although in metaphysical strict- 
ness it is true that there is no entirely exterior denomination 
(denominatio pure extrinseca) because of the real connection of 
all things.] 

§ 6. Ph. [I think that relation is only between two things.] 

Th. [There are, however, examples of relation between sev- 
eral things at once, as that of order or that of a genealogical 
tree, which expresses the rank and connection of all the terms 
or members, and even a figure like that of a polygon includes 
the relation of all the sides.] 

§ 8. Ph. It is well to consider also that the ideas of rela- 
tions are often clearer than those of the things which are the 
subjects of the relation. Thus the relation of father is clearer 
than that of man. 

Th. [That is because this relation is so general that it may 
also suit other substances. Moreover, as a subject may have 
clearness and obscurity, the relation might be grounded in the 
clear. But if the form itself of the relation involved the 
knowledge of that which is obscure in the subject, it would 
participate in this obscurity.] 

§ 10. Ph. The terms which necessarily lead the mind to other 
ideas than those which are supposed really to exist in the 
thing to which the term or word is applied are relative ; the 
others are absolute. 

Th. [You have well added this " necessarily " and you might 
add " expressly " or " at first" for you can think of black, for 
example, without thinking of its cause ; but it is by remaining 
within the limits of a knowledge which presents itself at first 
and which is confused or very distinct, but incomplete ; the 
one when there is no resolution of the idea, the other when 
you limit it. Otherwise there is no term so absolute or so 
loose as not to include relations and the perfect analysis of 
which does not lead to other things and even to all others ; so 
that you can say that relative terms indicate expressly the rela- 
tion they contain. I here oppose the absolute to the relative, 
and it is in another sense that I have opposed it above to the 
limited.'] 



ch. xxvi] ON HUMAN UNDERSTANDING 237 

CHAPTER XXVI 

OF CAUSE AND EFFECT AND SOME OTHER RELATIONS 

§§ 1, 2. Ph. Cause is that which produces a simple or in- 
complex idea ; effect is that which is produced. 

Th. [I see, sir, that you often understand by idea the objec- 
tive reality of the idea or the quality which it represents. You 
define only efficient cause, as I have already remarked above. 
You must admit that, in saying that efficient cause is that 
which produces and effect that which is produced, you make 
use only of synonyms. It is true that I have heard you say a 
little more distinctly, that cause is that which makes another 
thing commence to exist, though this word "makes" passes 
over also the principal difficulty entirely. But that will be 
explained better elsewhere.] 

Ph. In order further to touch some other relations, I remark 
that there are terms employed to designate time which are 
ordinarily regarded as signifying only positive ideas, which 
are nevertheless relative, as young, old, etc., for they involve a 
relation to the ordinary duration of the substance to which 
you attribute them. Thus a man is called young at the age of 
twenty years, and very young at the age of seven years. But 
we call a horse old at twenty years, and a dog at seven. But 
we do not say that the sun and the stars, a ruby or a diamond, 
is young or old, because we do not know the ordinary periods 
of their duration. § 5. The same is true regarding place or 
extension, as when a thing is said to be high or low, great or 
small. Thus a horse which will be large according to the idea 
of a Welshman, appears very small to a Fleming ; each thinks 
of the horses which are raised in his country. 

Th. [These remarks are very good. It is true we some- 
times swerve a little from this sense, as when we say that a 
thing is old when comparing it not with those of its kind, but 
with other kinds. For example, we say that the world or the 
sun is very old. Some one asked Galileo if he believed that 
the sun was eternal. He replied : etemo no ma ben antico — 
eternal, no, but very ancient. 



238 LEIBNITZ'S CRITIQUE OE LOCKE [bk. h 



CHAPTER XXVII 

WHAT IDENTITY OK DIVERSITY IS 

§ 1. Ph. A relative idea of the greatest importance is that 
of identity or diversity. We never find and we cannot conceive 
it possible that two things of the same kind exist in the same 
time in the same place. Therefore when we ask whether a 
thing is the same or not, the question always relates to a thing 
which at such a time exists in such a place ; whence it follows 
that a thing cannot have two beginnings of existence, nor two 
things one beginning only in relation to the time and the 
place. 

Th. [It is always necessary that besides the difference of 
time and. place there be an internal principle of distinction, and, 
though there are many things of the same kind, it is never- 
theless true that none of them are ever perfectly alike : thus 
although time and place (i.e. external relation) serve us in 
distinguishing things which we do not easily distinguish by 
themselves, the things do not cease to be distinguishable in 
themselves. The essence (le precis) of identity and diversity 
consists, then, not in time and place, although it is true that 
the diversity of things is accompanied by that of time or of 
place, because they bring with them different impressions of 
the thing ; not to say that it is rather by the things that one 
place or one time must be distinguished from another, for in 
themselves they are perfectly alike, but they are not, there- 
fore, substances or complete realities. The mode of distin- 
guishing which you seem to propose here, as unique in things 
of the same kind, is based upon the supposition that penetra- 
tion is not conformable to nature. This supposition is reason- 
able, but experience indeed makes it evident that it is not 
closely applied here, when the question concerns distinction. 
We see, for example, two shadows or rays of light which in- 
terpenetrate, and we might invent for ourselves an imaginary 
world wherein bodies would act in the same way. But we do 
not cease to distinguish one ray from another by the very 
rate of their passage even when they cross each other.] 









CH. xxvn] ON HUMAN UNDERSTANDING 239 

§ 3. Ph. What is called the principle of individuation (prin- 
cipium individuationis) in the schools, where they torment 
themselves so much to know what it is, consists in existence 
itself which determines each being to a particular time and 
place incommunicable to two beings of the same kind. 

Th. The principle of individuation 1 reappears in individuals 
in the principle of distinction of which I just spoke. If two 
individuals were perfectly alike and equal and (in a word) 
indistinguishable in themselves, there would be no principle 
of individuation; and I even venture to assert that there 
would be no individual distinction or different individuals 
under this condition. This is why the notion of atoms is 
chimerical, and arises only from the incomplete conceptions 
of men. For if there were atoms, i.e. bodies perfectly hard 
and perfectly unalterable or incapable of internal change and 
capable of differing among themselves only in size and shape, 
it is plain that in the possibility of their being of the same 
shape and size they would then be indistinguishable in them- 
selves, and could be distinguished only by means of external 
denominations without an internal basis, which is contrary to 
the highest principles of reason. But the truth is that every 
body is alterable, and indeed actually changes so that it differs 
in itself from every other. I remember that a distinguished 
princess, 2 who is of a pre-eminently excellent mind, said one 

1 Leibnitz discussed this principle in his disputation for the degree of 
Bachelor of Philosophy, entitled, Disputatio metaphysica cle principio indi- 
vidui, which in his sixteenth year he publicly defended at Leipzig, March 30, 
1663 ; cf. Guhrauer, Leibniz. Leben, 1, 27 sq. This piece is found in Gerhardt, 
4, 15-26, where the title-page gives the date of the public defence, May 30, 
1663; Erdmann, 1-5; it has also been edited, with an extended critical intro- 
duction, from a copy found in the Library at Hannover by Dr. G. E. Guhrauer, 
and published at Berlin in 1837. J. H. von Kirchmann has published a German 
translation with elaborate and extensive notes in his Philos. Bibliothek, Bd. 
81, Die klein. philos. ivicht, Schriften G. W. Leibniz ; Bd. 82, Erlauterungen. 
For a recent discussion of the principle of individuality, cf. R. Eucken, The 
Fundamental Concepts of Mod. Philos. Thought, pp. 231-248. New York, 
1880. — Tk. 

2 Sophie Charlotte, 1668-1705, the first Queen of Prussia, the friend and in 
a certain sense the pupil of Leibnitz in philosophy. The Theodice'e originated 
in his philosophical conversations with her. Cf. Gerhardt, 6, 39; Erdmann, 
474 b. Leibnitz's correspondence with her is found in O. Klopp, Die Werke 
von Leibniz, Vol. 10, Hannover, 1877 ; the letters of philosophical importance 
in Gerhardt, 3, 343 sq. ; 6, 488 sq. ; 7, 544 ; the letter in G. 6, 499 sq. is translated 
in Duncan, Philos. Works of Leibnitz, 149 sq. Cf. also Kuno Fischer, Gesch. 
d. n. Philos., Vol. 2, p. 261 sq., 3d ed., 1889. — Tr. 



240 LEIBNITZ'S CRITIQUE OE LOCKE [bk. it 

day while walking in her garden that she did not believe 
there were two leaves perfectly alike. A gentleman of dis- 
tinction, who was walking with her, thought he would easily 
find some. But although he searched long, he was convinced 
by his eyes that he could always note the difference. We see 
by these considerations, hitherto neglected, how far we have 
wandered in philosophy from the most natural notions, and 
how far we have departed from the great principles of true 
metaphysic] 

§ 4. Ph. That which constitutes the unity (identity) of one 
and the same plant is the possession of such an organization 
of parts in a single body, as participates in a common life 
which endures while the plant subsists, although the parts 
change. 

Th. [The organization or configuration without an existing 
principle of life, which I call a monad, would not suffice to 
cause the continuance of idem numero or the same individual ; 
for the configuration can abide specifically without abiding 1 
individually. When a horseshoe is changed into copper in a 
mineral spring of Hungary, the same figure in kind remains, 
but not the same as an individual ; for the iron is dissolved, 
and the copper, with which the water is impregnated, is pre- 
cipitated and insensibly takes its place. ISTow figure is an 
accident which does not pass from one subject to another (de 
subjecto in subjectum). So we must say that bodies as well 
organized as others do not remain the same in appearance, 
and, speaking strictly, not at all. It is almost like a river 
which always changes its water, or like the ship of Theseus 
which the Athenians were always repairing. 2 But as regards 

1 Erdmanu and Jacques omit " specifiquement, sans demeurer," the reading 
of Gerhardt. — Tu. 

2 Cf. Plato, Phsedo. 58 A; Xenophon, Memorabilia, 4, 8, 2. The sacred 
ship, sent yearly to Delos by the Athenians in consequence of a vow made to 
Apollo by Theseus when on his way to Crete with the seven youths and seven 
maidens, the annual tribute of the Athenians to the Minotaur, that if rescued 
he would send annually to Delos a ship with gifts and sacrifices as a thank- 
offering for their deliverance, was repaired piece by piece as necessary, so 
that in form and appearance it remained the same old ship in which Theseus 
himself sailed, while its substance continually changed. The vessel served 
the philosophers as an instance in discussions concerning identity and what 
constitutes it, and as an illustration of a numerical substance continuously 
the same, though constantly changing by the decay and rejection of old and 
the growth and acquisition of new parts, as in the case of the living body. 
— Ta. 



en. xxvn] ON HUMAN UNDERSTANDING 241 

substances, which are in themselves a true and real substantial 
unity, to which may belong actions properly called vital, and 
as regards substantial beings, quce uno spiritu continentur, in 
the words of an ancient jurisconsult, 1 i.e. which a certain 
indivisible spirit animates, you are right in saying that they 
remain perfectly the same individual through this soul or this 
spirit which constitutes the ego in thinking beings.] 

§ 5. Ph. The case is not very different in animals and in 
plants. 

Th. [If vegetables and animals have no soul, their identity 
is only apparent ; but if they have, individual identity is in 
truth strictly speaking there, although their organized bodies 
do not preserve it.] 

§ 6. Ph. This also shows wherein the identity of the same 
man consists, viz. in the fact alone that he enjoys the same 
life, continued by particles of matter which are in a perpetual 
flux, but which in this succession are vitally united with the 
same organized body. 

Th. [That may be understood in my sense. In fact, the 
organized body is not the same from one moment to another ; 
it is only equivalent. And if it were not related to the soul, 
there would no longer be the same life or vital union. Thus 
this identity would be only apparent.] 

Ph. Whoever shall connect the identity of man with any- 
thing else than a well-organized body, in a certain instant, and 
which thence continues in this vital organization by a succes- 
sion of different particles of matter which are united to it, 
will have difficulty in making an embryo, a man of years, a 
fool, and a wise man the same man, unless it follows from this 
supposition that it is possible for Seth, Ismael, Socrates, Pilate, 
St. Augustine 2 to be one and the same man, . . . and this would 
agree still worse with the notions of those philosophers who 
recognize transmigration and believe that men's souls can be 
sent for punishment of their irregularities into the bodies of 
animals ; for I do not believe that any one who was assured 
that the soul of Heliogabalus existed in a hog would mean 
that this hog was a man, and the same man as Heliogabalus. 

1 Sextus Pompcmius, died 138 A.r>. The phrase occurs in the Digest, 41, 3, 
30, Vol. 2, p. 522, ed. Th. Mommsen, Berlin: Weidmann, 1870. — Tr. 

2 Locke has " St. Austin," Philos. Works, Vol. 1, p. 463 (Bohn's ed.). — Tr. 

K 



242 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

Tli. [There is here a question of name and of thing. As for 
the thing, the identity of one and the same individual sub- 
stance can be maintained only by the conservation of the same 
soul, for the body is in a continual flux, and the soul does not 
dwell in certain atoms appropriated to itself, nor in a little 
incorruptible (indomptable) bone, such as the Luz 1 of the 
Rabbis. Moreover there is no transmigration by which the 
soul wholly leaves its body and passes into another. It keeps 
always, even in death, an organized body, a part of the pre- 
ceding, although what it keeps is always subject to insensible 
dissipation and to reparation, and indeed to undergoing in a 
certain time a great change. Thus instead of a transmigra- 
tion of the soul there is a transformation, envelopment, or 
development, and finally a fluxion of the body of this soul. 
Van Helmont, 2 the son, thought that souls pass from body to 
body, but always within their kind, so that there will always 
be the same number of souls of one and the same kind, and 
consequently the same number of men and of wolves, and that 
the wolves if diminished or extirpated in England would be 
proportionally increased elsewhere. Certain meditations pub- 

1 The bone which the Jews regarded as incapable of decay, remaining until 
the last day and forming the nucleus of the resurrection body. Schaarschmidt 
says: " According to the opinion of the Rabbis, says Ulrich in his note to this 
place, the body which we are to receive at the resurrection is already at hand 
iu our backbone. This body or bone, l*h [Luz) , as it is properly called, they 
held for this reason to be incorruptible. In the Jalkut chadasch, Fol. 142, 
title Maschiach, n. 44, the following account is given of it: This bone decays 
not, and the holy giving God will make it soft with the dew, and out of it will 
build the body. The reason why this little bone is not to be exposed to cor- 
ruption, they place in the fact that it has not enjoyed the pleasures of this 
world, as the rest of the members. This doctrine is with them no empty 
speculation. The old Rabbis of blessed memory have not only seen this bone, 
but have found it actually so strong and hard that their hammer and rock 
flew in pieces before this little bone was injured in the least. See Askath 
Eochel in the 4th part," etc. — Tr. 

2 Francois Mercure van Helmont, 1618-1698, a particular friend of the 
Countess of Connaway, in whose Opuscula philosophica, Bk. I., chap. 6, §§ 7, 
8, and chap. 7, § 4, London, 1690, this view of his is found in detail. On 
Leibnitz's relations with Van Helmont, cf. Stein, Leibniz and Spinoza, pp. 
210 sq., and the references in Stein's notes; also Beilagen, XV, XVI., op. cit. 
pp. 329-337. Leibnitz composed for him, at the request of his cousin, the 
Baroness of Merode, a Latin epitaph; cf. Burckhard, Historia Biblioth. Au- 
gusts, II., p. 326; also Stein, op. cit. pp. 336-337. Leibnitz treats of him and 
his doctrine in his Miscellanies, cf. Otium Hanoveranum, ed. J. F. Feller, 
pp. 226-230, Lipsite, 1718. — Tr. 



OH. xxvii] ON HUMAN UNDERSTANDING 243 

lished in France would also seem to tend in that direction. If 
transmigration is not taken strictly, i.e. if any one thought 
that souls dwelling in the same subtile body change only from 
a coarser body, it would be possible, even to the passage of 
the same soul into a body of a different kind after the fashion 
of the Brahmins and Pythagoreans. But all that is possible 
is not for that reason conformed to the order of things. But 
the question whether, in case such a transmigration were true, 
Cain, Ham, and Ismael, supposing, according to the Babbis, 
they were the same soul, would deserve to be called the same 
man, is only one of name ; and I have observed that the cele- 
brated author, whose opinions you have maintained, recognizes 
and explains it very well (in the last paragraph of this chapter) . 
The identity of substance would occur therein, but in case 
there were no connection of memory between the different 
persons, as the same soul would make, there would not be 
sufficient moral identity to say that it would be one and the 
same person. And if God willed that the human soul should 
go into the body of a hog, forgetting the man and performing 
no rational acts, it would not constitute a man. But if in the 
body of the animal it had the thoughts of a man, and even of 
the man whom it animated before the change, like the Golden 
Ass of Apuleius, one would perhaps have no difficulty in say- 
ing that the same Lucius, who had come into Thessaly to see 
his friends, lived under the ass's hide, where Photis had put 
him in spite of herself, and wandered from master to master 
until the roses he ate restored him to his natural form. 1 

i Cf. Apuleius, Metamorph., Bk. III., Vol. 1, pp. 229 sq. ; Bk. XI., pp. 770 sq., 
edition in 6 vols., paging continuous, A. J. Valpy, London, 1825. The Meta- 
morphoses is in contents very similar to a work entitled, Aou'kios ij ovos (Lucius 
or Ass), ascribed to Lucian, a contemporary of Apuleius who flourished about 
160 a. d., and is most probably an imitation of it. The incidents and adven- 
tures in both are nearly identical, the names only being changed, both writers, 
however, calling the hero Lucius. In the course of his adventures Lucius 
became involved in a love-affair with a waiting-woman by the name of Fotis, 
whose mistress practised the art of magic, and changed at will herself and 
others into various animals by the use of certain ointments. Lucius, very 
desirous to learn all about this wonderful art, finally persuaded Fotis, who 
claimed that she understood her mistress's art, to try it on him. She did so, 
intending to change him into an owl, into which form her mistress in the 
sight of them both had just changed herself, but in her haste and confusion 
using the wrong ointment, she changed him, "in spite of herself," into an ass. 
The work of Apuleius is much more extended than that of Lucian, and, in 



244 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

§ 9. Ph. I think we can boldly advance the idea that who- 
ever of us saw a creature made and formed like himself, 
although it had never exhibited more reason than a cat or a 
parrot, would not cease to call it a man ; or if he heard a 
parrot discoursing rationally and in a philosophical manner 
would call or think it only a parrot, and would say of the 
former of these animals that it is an uncultivated man, dull 
and destitute of reason, and of the latter that it is a parrot full 
of intelligence and good sense. 

Th. [I should be more of the same opinion upon the second 
point than upon the first, although there is still something to 
be said thereupon. Few theologians would be venturesome 
enough to agree at once and absolutely to the baptism of an 
animal in human form, but without appearance of reason, if 
he were taken while young in the woods and some priest of 
the Eoman church should perhaps say conditionally, if you 
are a man I baptize you; for they would not know whether 
he is of the human race and' whether a rational soul dwells 
therein, and this might be an ourang-outang, an ape externally 
very like a man, such as that one whom Tulpius 1 speaks of as 
having seen, and that one an account of whose anatomy a 
learned physician has published. It is certain (I admit) that 
man can become as stupid as an ourang-outang, but the interior 
of a rational soul would abide there in spite of the suspension 
of the exercise of reason as I have explained above ; thus it is 
a point of which we cannot judge by appearances. As for the 
second case, nothing prevents there being rational animals of 
a different kind from ourselves, as those inhabitants of the 
poetic kingdom of the birds in the sun, where a parrot having 
come from this world after its death, saved the life of a trav- 
eller who had treated him well here below. But if it hap- 
pened, as it happens in the country of the fairies or of Mother 

spite of its irony, abounds in a mysticism not found in the AvVios ij ovos. A brief 
sketch of Lucian's work may be found in the Encyclopsedia Britannica, 
9th ed., under the article "Lucius." On Apuleius, and the relation of his 
work to that of Lucian, cf. Teuffel, Gesch. d. Rom. Lit., § 367, 3, 4th ed., 
Leipzig : B. G. Teubner, 1882 ; § 367, 1, 5th ed. by Ludwig Schwabe, Leipzig : 
Teubner, 1890, and from this ed., the English translation in 2 vols., by Geo. 
C. W. Warr, M.A., Geo. Bell and Sons, London, 1891. — Tr. 

1 Nicolas Tulp, 1593-1674, a Dutch physician and magistrate, in Bk. III., 
chap. 56, of his Observationum medicarum libri tres, Amsterdam, 1641, 8th ed., 
revised with additions, Leyden, 1752. — Tr. 



oh. xxvn] ON HUMAN UNDERSTANDING 245 

Goose, that a parrot was a transformed daughter of a king and 
became known as such while speaking, doubtless her father 
and mother would caress her as their daughter whom they 
thought they possessed though concealed under this strange 
form. I should not oppose myself, however, to him who should 
say that in the Golden Ass as the self or the individual re- 
mained for the sake of the same immaterial spirit, so Lucius 
or the person remained for the sake of the apperception of 
this ego, but that this is no longer a man ; as in fact it seems 
necessary to add something of the figure and constitution of 
the body to the definition of man, when we say that he is a 
rational animal ; otherwise in my view the genii would also be 
men.] 

§ 9. Ph. The word person carries with it a thinking and 
intelligent being, capable of reason and reflection, that can 
consider itself indeed as the same, as one and the same thing 
which thinks at different times and in different places ; which 
it does only by that consciousness l which it has of its own 
acts. And this knowledge always accompanies our sensations 
and our present perceptions [when they are sufficiently dis- 
tinguished, as I have more than once before remarked] and it 
is by this that each one is to himself what he calls himself. 
It is not considered in this case whether the same self is con- 
tinued in the same or in different substances. For since 
consciousness 2 always accompanies thought, and is that which 
makes each one to be what he calls himself and by which he 
is distinguished from every other thinking being ; it is also in 
this alone that personal identity consists, or that which makes 
a rational being always to be the same ; and as far as this 
consciousness can be extended over actions or thoughts already 
past, so far the identity of this person extends, and the self 
is at present the same as it was then. 

Th. [I am also of this opinion that consciousness or the 
perception of the ego proves a moral or personal identity. 
And it is by this that I distinguish the incessability 3 of the 
soul of an animal from the immortality of the soul of man ; 

1 The French is " sentiment." — Tr. 

2 The French text is "la conscience (consciousness ou conscienciosite)," 
Gerhardt ; " consciosite," Erdmann and Jacques. — Tr. 

3 The French is " incessabilite'," i.e. continuity or perpetuity. — Tr. 



246 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

both preserve physical and real identity, but as for man, lie is 
conformed to the rules of divine providence so that the soul 
preserves also identity moral and apparent to ourselves, in order 
to constitute the same person, capable consequently of feeling 
chastisements and rewards. It seems that you, sir, hold that 
this apparent identity could be preserved, if there were no 
real identity. I should think that that might perhaps be by 
the absolute power of God, but according to the order of things, 
identity apparent to the person himself who perceives the 
same, supposes real identity to every proximate transition, 
accompanied by reflection or perception of the ego, a perception 
intimate and immediate naturally incapable of deception. If 
man could be merely a machine and with that have conscious- 
ness, it would be necessary to be of your opinion, sir ; but I 
hold that this case is not possible at least naturally. Neither 
would I say that personal identity and even the self do not 
dwell in us and that I am not this ego which has been in the 
cradle, under pretext that I no more remember anything of 
all that I then did. It is sufficient in order .to find moral 
identity by itself that there be a middle bond of consciousness 
between a state bordering upon or even a little removed from 
another, although a leap or forgotten interval might be mingled 
therein. Thus if a disease had caused an interruption of the 
continuity of the bond of consciousness so that I did not know 
how I came into the present state, although I remember things 
more remote, the testimony of others could fill the void in my 
memory. I could even be punished upon this testimony, if I 
had just done something bad of deliberate purpose in an inter- 
val that I had forgotten a little after on account of this 
disease. And if I had just forgotten all past things and 1 
would be obliged to let myself be taught anew even to my 
name and even to reading and writing, I could always learn 
from others my past life in my previous state, as I have kept 
my rights without its being necessary for me to share them 
with two persons, and to make me the heir of myself. All 
this suffices to maintain moral identity, which makes the same 
person. It is true that if others should conspire to deceive 
me (as I might indeed be deceived by myself, by some vision, 
dream, or illness, believing that what I had dreamed had hap- 
1 Gerhardt reads : "et"; Erdmann aud Jacques: " que," so that. — Tr. 



ch. xxvii] ON HUMAN UNDERSTANDING 247 

pened to me) the appearance would be false. But there are 
cases in which we can be morally certain of the truth upon the 
relation of another, and with God whose social connection 
with us constitutes the principal point of morality, the error 
cannot have place. i/As for the self, it will be well to dis- 
tinguish it from the phenomenon of self and from conscious- 
ness. The self constitutes identity real and physical, and the 
phenomenon of self, accompanied by truth, joins thereto per- 
sonal identity. Thus not wishing to say that personal iden- 
tity extends no farther than memory, I would say still less 
that the self or physical identity depends upon it. Real and 
personal identity is proved with the utmost possible certainty 
by present and immediate reflection ; it is proved sufficiently 
for ordinary purposes by our memory of the interval or by the 
conspiring testimony of others. But if God should change in 
an extraordinary manner real identity, personal identity would 
remain, provided man preserved the appearances of identity, 
as well the internal (that is to say, consciousness) as the 
external, like those which consist in that which appears to 
others. Thus consciousness, is not the sole means for consti- 
tuting personal identity, 'aiicl the testimony of another or even 
other proofs can supply it. But there is some difficulty if 
contradiction occurs between those diverse appearances. Con- 
sciousness may be silent as in forgetfulness ; but if it should 
alter very clearly things which were contrary to the other 
appearances, we should be embarrassed in the decision and as 
it were suspended sometimes between two possibilities, that 
of the error of our memory and that of some deception in 
external appearances.] 

§ 11. Ph. [You will say] that the members of the body of 
every man are a part of himself [and that thus, the body 
being in a perpetual flux, the man cannot remain the same]. 

Th. [I should rather prefer to say that the I and the He are 
without parts, because it is said, and with reason, that the 
same substance, or the same physical ego, is really preserved. 
But we cannot say, speaking according to the exact truth of 
things, that the same whole is preserved when a part is lost. 
Now whatever has corporeal parts cannot fail to lose some of 
them at every moment.] 

§ 13. Ph. The consciousness which one has of his past 



248 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

actions cannot be transferred from one thinking substance to 
another [and it would be certain that the same substance 
abides, because we feel ourselves the same], if this conscious- 
ness were a single and indeed an individual act [i.e. if the act 
of reflecting were the same as the act upon which you reflect 
in perceiving it]. But as it is only an actual representation 
of a past act it remains to be shown how it is impossible for 
what has never really been to be represented to the mind as 
truly having been. 

Th. [Memory after an interval may deceive; we have ex- 
perienced it often, and there are means of conceiving a natural 
cause of this error. But present or immediate memory, or the 
memory of what passed immediately before, i.e. the conscious- 
ness or reflection which accompanies internal action, cannot 
naturally deceive ; otherwise we should not be certain indeed 
that we think of this or that thing, for this statement is 
made internally only of the action already past, and not in 
connection with the action itself. Now- if these internal, 
immediate experiences are not certain, there will be no truth 
of fact of which we can be assured. And I have already said 
that there may be intelligible reasons for the error which ex- 
poses itself in perceptions mediate and external, but in those 
immediately internal we cannot find any unless by recurring 
to the omnipotence of God.] 

§ 14. Ph. As for the question whether the same immaterial 
substance remaining there may be two distinct persons, see 
upon what it is based. It is this : If the same immaterial 
being can be deprived of all consciousness (sentiment) of its past 
existence, and lose it wholly, without the power of ever recov- 
ering it, so that beginning, so to speak, a new account from a 
new period, it has a consciousness (conscience) which cannot 
extend beyond this new state. All those who believe in the 
pre-existence 1 of souls are evidently of this mind. I have seen 

1 I.e. existence before this earthly life. The doctrine was set forth with 
more or less fulness by the Pythagoreans, Plato, Philo, Origen, and more 
recently, among others, by Lessing, Erziehung des Menschengeschlechtes, 
§ 94 sq. ; Kant, Die Religion innerhalb der Grenzen der blossen Vernunft, 
Bk. I., 4; Julius Mtiller, Die Christ. Lehre von der Silnde, Bk. IV., chap. 4, 
Vol. 2, pp. 486 sq., Breslau, 1844, and English translation of the same, 2d ed., 
from the 5th German ed., Halle, 1866, Vol. 2, pp. 357 sq., Edinburgh: T. & T. 
Clark, 1868. The doctrine has been used chiefly to explain the origin of 






ch. xxvn] ON HUMAN UNDEKSTANDING 249 

a man who was persuaded that his soul had been the soul of 
Socrates ; and I can assure you that in the post he filled and 
which was not one of little importance he passed for a very- 
rational man, and he appeared by his works which have seen 
the light to lack neither intelligence nor learning. Now souls 
being * indifferent to any portion of matter whatever this may be, 
as far as we. can know it by their nature, this supposition 
(of the same soul passing into different bodies) involves 
no apparent absurdity. But he who now has no conscious- 
ness of that which Nestor or Socrates ever did or thought, 
does he or can he conceive himself the same person as Nestor 
or Socrates? Can he take part in the actions of these two 
ancient Greeks? Can he attribute them to himself or think 
them his own actions rather than those of some other man 
who has already existed? He is no more the same person 
with one of them than if the soul now present in him had 
been created when it began to animate the body which it now 
possesses. This would no more contribute to make him the 
same person as Nestor, than if some of the particles of matter 
which once formed part of Nestor were now a part of this 
man. For the same immaterial substance without the same 
consciousness no more makes the same person to be united to 
such or such a body than the same particles of matter, united to 
a body without a common consciousness, can make the same 
person. 

Th. [An immaterial being or a spirit cannot be stripped 
of all perception of its past existence. There remain for it 
some impressions of all that has formerly happened to it, and 
it even has some presentiments of all that will happen to it ; 
but these feelings are most often too small to be capable of 
being distinguished and perceived, although they may perhaps 
sometime be developed. This continuation and bond of per- 

evil or sin; but it is an explanation which does not explain, its assumed solu- 
tion being merely an evasion ol the real difficulty by pushing the problem 
back unsolved into past time. Cf. O. Pfleiderer, Beligionsphilosophie auf 
gesch. Grundlage, Vol. 2, p. 382, 2d ed., Berlin: G. Reimer, 1884; English 
translation, Vol. 4, p. 29, London : Williams & Norgate, 1888. For a critique 
of the theory as held by Julius Muller, cf. I. A. Dorner, System d. christlichen 
Glaubenslehre, § 77, 3 ; § 82, 2, Berlin : Wm. Hertz, 1881 ; English translation, 
Edinburgh: T. & T. Clark, 1882. — Tr. 

1 Gerhardt and Jacques read: "les ames estant" (" e'tant," J.) ; Erdmann 
reads: "tant." — Tr. 



250 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

ceptions constitutes in reality the same individual, but the 
apperceptions (i.e. when past feelings are perceived), prove 
besides a moral identity and make real identity appear. The 
pre-existence of souls does not appear to us through our per- 
ceptions, but if it were true, it might sometime make itself 
known. Thus it is not reasonable that the restitution of 
memory becomes forever impossible, the insensible percep- 
tions (whose use I have set forth on so many important occa- 
sions) serving here, moreover, to preserve the seeds. The late 
Henry More, a theologian of the English church, was con- 
vinced of the truth of pre-existence and ha.s written in its 
defence. 1 The late M. Van Helmont, the son, went much 
farther, as I just said, and believed in the transmigration of 
souls, but always into bodies of one and the same species, so 
that according to him the human soul always animated a man. 
He believed with some Kabbis in the passage of the soul of 
Adam into the Messiah as into the new Adam. And I do not 
know but that he thought he had himself been some ancient, 
altogether clever man that he was elsewhere. Now if this pas- 
sage of souls was true, at least in the possible way that I have 
explained above (but which does not appear probable), i.e. 
that souls, keeping their subtile bodies, pass at once into other 
coarse bodies, the same individual would always subsist in 
Nestor, in Socrates, and in any modern, and he could even 
make his identity known to any one who would penetrate 
sufficiently into his nature, on account of the impressions or 
marks which would there remain of all that Nestor or Soc- 
rates have done, and which any genius sufficiently penetrat- 
ing could there read. But if the modern man had no means 
internal or external of knowing what he had been, it would be 
as far as the moral is concerned as if he had not been. But 
it appears that nothing is neglected in the world in relation 
even to the moral, because God is the monarch thereof whose 
government is perfect. Souls according to my hypothesis are 
not indifferent regarding any portion of matter whatever, as it 
seems to you ; on the contrary, they originally express those 
portions to which they are and ought to be united by nature. 

1 Of. Opera, 1, 750-754, London, 1679; following the Kabbala, he thinks all 
souls were created at the same time as the world, 2, 539 ; and, like Leibnitz, 
them as always united with some kind of matter, 2, 395, 396. — Tr. 






ch. xxvn] ON HUMAN UNDERSTANDING 251 

Thus, if they pass into a new body coarse or sensible, they 
would always preserve the expression x of all that they had 
perceived in the old, and it would even be necessary for 
the new body to manifest it so that the individual continuity 
will always have its real marks. But whatever our past state 
may have been, the effect it leaves cannot always be for us 
apperceivable. The clever author of the Essay on Understand- 
ing, whose views you had espoused, had remarked (Bk. II., 
chap. 27. On Identity, § 27) that a part of these suppositions 
or fictions of the passage of souls, assumed as possible, is 
founded upon the common view of the mind as not only inde- 
pendent of matter but also as indifferent to every sort of mat- 
ter. But I hope that what you have said, sir, on this subject 
here and there will serve to clear up this doubt and to make 
better known what is naturally possible. We see thereby 
how the acts of an ancient might belong to a modern who had 
the same soul, although he did not perceive them. But if he 
should come to recognize it, still more would personal identity 
follow. For the rest a portion of matter passing from one 
body into another does not constitute the same human indi- 
vidual, nor what is called the ego, but it is the soul which 
constitutes it.] 

§ 16. Ph. It is, however, true that I am as much concerned 
and as justly responsible for an action done a thousand years 
since, which is now adjudged as mine by this present con- 
sciousness (self-consciousness 2 ) thereof, as having been done 
by myself, as I am for what I have just done in the preced- 
ing moment. 

Th. [This view of having done something may deceive in 
distant actions. Men have taken as true by force of repetition 
what they dreamed, or what they invented ; this false view 
may embarrass, but it cannot make them punishable, unless 
others agree therewith. On the other hand, you can be respon- 
sible for what you have done, when you have forgotten it, 
provided the action be verified elsewhere.] 

§ 17. Ph. Every one finds every day that while his little 

1 Gerhardt and Erdmann read: " l'expression " ; Jacques: "l'inipression." 
,-Te. 

' A Gerhardt's reading ; Erdmann and Jacques have, as before (p. 245, note 2) , 
" consciosite ou consciousness." — Tr. 



252 LEIBNITZ'S CRITIQUE OF LOCKE [bk. n 

finger is comprehended under this consciousness, it constitutes 
as much a, part of himself (of him) as that which is most so. 

Th. [I have said (§ 11) why I would not advance the view 
that my finger is a part of me ; but it is true that it belongs to 
me and that it constitutes a part of my body.] 

Ph. [Those who hold another view will say that] in the 
event of this little finger being separated from the rest of the 
body, if this consciousness accompanies the little finger and 
leaves the rest of the body, it is evident that the little finger 
would be the person, the same person, and that then the self 
would have nothing to do with the rest of the body. 

Th. [Nature does not admit these fictions, which are de- 
stroyed by the System of Harmony or the perfect correspon- 
dence of the soul and the body.] 

§ 18. Ph. It seems, however, that if the body should con- 
tinue to live and to have its particular consciousness, in which 
the little finger had no share, and that meanwhile the soul 
was in the finger, the finger could not own any of the actions 
of the rest of the body, and we could no longer impute them 
to it. 1 

Tli. [The soul also which would be in the finger would not 
belong to this body. I admit that if God caused conscious- 
nesses to be transferred to other souls, it would be necessary 
to treat them in accordance with moral notions, as if they 
were the same ; but this would disturb the order of things 
without reason, and make a divorce between the appercepti- 
ve and the truth, which is conserved by the insensible percep- 
tions, which would not be reasonable, because the perceptions 
insensible at present may some day be developed, for there is 
nothing useless, and eternity gives a large field for changes.] 

§ 20. Ph. Human laws do not punish the madman for the 
acts which the sober 2 man does, nor the sober man for what 
the madman does, thereby making them two persons. Thus 
they say : he is beside himself. 

Th. [The laws threaten to chastise and promise to recom- 
pense in order to prevent bad and further good acts. Now a 
madman may be such that the threats and promises do not 
operate sufficiently upon him, reason no longer being master ; 



1 Locke reads : " him," Philos. Works, Vol. 1, p. 475 (Bohn's ed.). — Tr. 

2 Locke's word; Philos. Works, Vol. 1, p. 475 (Bohn's ed.). — Tr. 






ch. xxvn] ON HUMAN UNDERSTANDING 253 

thus in proportion to his weakness the severity of the pain 
should cease. On the other hand we wish the criminal to feel 
the effect of the evil he has done in order that he may fear 
further to commit crimes, but the madman not being sensitive 
enough, we are well content to wait a good while in order to 
execute the sentence which punishes him for what he did 
when sober. Thus what the laws or the judges do in these 
instances comes not from the conception of two persons.] 

§ 22. Ph. In fact in the party whose opinions I represent 
to you, this objection is made, that if a man who is drunk and 
who is afterwards no longer drunk, is not the same person, he 
should not be punished for what he did while drunk, since he 
is no longer conscious of his act. But they reply that he is 
altogether as much the same person as a man who during his 
sleep walks and does many other things and who is responsi- 
ble for all the evil he has happened to do in that state. 

Th. [There is much difference between the acts of a 
drunken man and those of a true and recognized somnambu- 
list. We punish drunkards because they can avoid drunken- 
ness and can even have some memory of pain while drunk. 
But it is not so much within the power of somnambulists to 
abstain from their nocturnal walk and from what they do. 
But if it were true that by giving them a good flogging we could 
make them stay in bed, we should be right in doing it, and we 
should not fail either, although this would be rather a remedy 
than a punishment. In fact it is said that this remedy has 
restored them.] 

Ph. Human laws punish both in accord with a justice con- 
formed to the mode in which men understand things, because 
in these sorts of cases they cannot certainly distinguish what 
is real from what is counterfeit; thus ignorance is not re- 
ceived as an excuse for what they have done while drunk or 
asleep. The deed is proved against the one who has done it, 
and you cannot prove in his case lack of consciousness. 

Th. [The question is not so much about this, as about what 
must be done when it has been verified, as it may be, that the 
drunkard or somnambulist were beside themselves. In this 
case the somnambulist would be considered only as a maniac ; 
but as drunkenness is voluntary, and the disease is not, the one 
is punished but not the other.] 



254 LEIBNITZ'S CllITIQUE OF LOCKE [bk. ii 

Ph. But in the great and terrible day of judgment, when 
the secrets of all hearts shall be uncovered, it is right to think 
that no one will have to answer for what is wholly unknown 
to him and that each one will receive what is due him, his 
own conscience accusing or excusing 1 him. 

Th. I do not know whether it will be necessary for the 
memory of man to be exalted at the day of judgment in order 
for him to remember all he had forgotten, or whether the 
knowledge of others and above all of the just judge who can- 
not be deceived will not suffice. We might devise a fiction lit- 
tle agreeing with the truth, but nevertheless conceivable, to the 
effect that a man at the day of judgment believed he had 
been bad and that the same appeared true to all other created 
spirits, who would be able to judge of it, without its having 
been true : could we say that the supreme and just judge, who 
alone knows the contrary, could condemn this person and 
judge contrary to his knowledge ? 2 Yet it seems that that 
would follow from the notion you gave of moral personality. 
You will perhaps say that if God judges contrary to appear- 
ances he will not be sufficiently glorified and will bring pain 
upon others ; but the reply could be made that he is for him- 
self his unique and supreme law, and that in this case others 
should consider themselves mistaken.] 

§ 23. Ph. Could we suppose either two distinct and incom- 
municable consciousnesses acting by turns in the same body, 
the one constantly during the day, the other by night, or that 
the same consciousness acts at intervals in two different bodies ; 
I ask if, in the first case, the day and night man, if I may 
so express myself, would not be two as distinct persons as 
Socrates and Plato, and in the second case would he not be a 
single person in two distinct bodies ? It matters not that this 
same consciousness which affects two different bodies, and 
these consciousnesses which affect the same body at different 
times, belong the one to the same immaterial substance, and 
the tw T o others to two distinct immaterial substances, which 
introduce these different consciousnesses into these bodies, 

1 Erdmann and Jacques omit: "ou excuse." — Tr. 

2 Gerhardt reads : "juger contre ce qu'il sait?" Erdmann and Jacques: 
"juger contre ce qu'ils font?" i.e. "pass a judgment contrary to what they 
do." — Tr. 



ch. xxvn] ON HUMAN UNDEESTANDING 255 



since personal identity would equally be determined by the 
consciousness, whether that consciousness were attached to 
some individual immaterial substance or not. Further, an 
immaterial thinking thing may sometimes lose sight of its 
past consciousness, and recall it anew. Now suppose these 
intervals of memory and forgetfulness return with every day 
and night, then you have two persons with the same immate- 
rial spirit. Whence it follows that the self is not determined 
by the identity or diversity of substance, which it cannot be 
sure of, but only by the identity of consciousness. 

Th. [I admit that if all the appearances were changed and 
transferred from our spirit to another, or if God made an 
exchange between two spirits, giving the visible body and the 
appearances and consciousnesses of the one to the other, per- 
sonal identity, instead of being attached to that of substance, 
would follow the constant appearances which human morality 
must have in view ; but these appearances would not consist 
in the consciousnesses alone; and it will be necessary for God to 
make the exchange not only of the apperceptions or conscious- 
nesses of the individuals in question, but also of the appear- 
ances which present themselves to others regarding these 
persons, otherwise there would be a contradiction between 
the consciousnesses of the one and the testimony of the others, 
which would disturb the moral order of things. But you 
must also agree with me that the divorce between the insensi- 
ble and sensible world, i.e. between the insensible perceptions 
which would remain in the same substances, and the appercep- 
tions which would be changed, would be a miracle, as when 
you suppose that God makes the vacuum ; for I have stated 
above why that is not in agreement with the natural order. 
Here is another supposition much more suitable : it may be 
that in another place in the universe or at another time a globe 
may be found which does not differ sensibly from this earthly 
globe, in which we live, and that each of the men who inhabit 
it does not differ sensibly from each of us who corresponds to 
him. Thus there are at once more than a hundred million pairs 
of similar persons, i.e. of two persons with the same appear- 
ances and consciousnesses ; and God might transfer spirits 
alone or with their bodies from one globe to the other without 
their perceiving it ; but be they transferred or let alone, what 



256 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

will you say of their person or self according to your authors ? 
Are they two persons or the same? since the consciousness 
and the internal and external appearance of the men of these 
globes cannot make the distinction. It is true that God and 
the spirits capable of seeing the intervals and external rela- 
tions of times and places, and even internal constitutions, 
insensible to the men of the two globes, could distinguish 
them ; but according to your hypotheses consciousness alone 
discerning the persons without being obliged to trouble itself 
with the real identity or diversity of the substance, or even 
of that which would appear to others, how is it prevented 
from saying that these two persons who are at the same time 
in these two similar globes, but separated from each other by 
an inexpressible distance, are only one and the same person ; 
which is, however, a manifest absurdity. For the rest, speak- 
ing of what may be in the course of nature, the two similar 
globes and the two similar souls of the two globes would 
remain so only for a time. For since there is an individual 
diversity, this difference must consist at least in the insensible 
constitutions which must be developed in the course of time.] 

§ 26. Ph. Suppose a man punished now for what he has 
done in another life and of which he could cause himself to 
have absolutely no consciousness ; what difference is there 
between such treatment and that which would be done him in 
creating him miserable ? 

Th. [The Platonists, disciples of Origen, some Hebrews 
and other defenders of the pre-existence of souls believed that 
the souls of this world were placed in imperfect bodies, in 
order to suffer for the crimes committed in a preceding world. 
But it is true, if they neither know nor have ever learned the 
truth, neither by recall of memory, nor by any traces, nor by 
the knowledge of another, you cannot call it punishment ac- 
cording to ordinary notions. There is, however, some room 
for doubt, while speaking of punishments in general, whether 
it is absolutely necessary that those who suffer should one day 
learn the reason for their suffering, and whether it would not 
very often suffice that better informed minds should find 
therein a motive for glorifying the divine justice. However, 
it is more likely, at least in general, that the sufferers will 
know the reason of their suffering.] 






ch. xxvn] ON HUMAN UNDERSTANDING 257 

§ 29. Ph. [Perhaps in the main yon can agree with my 
author who concludes his chapter on identity by saying : that 
the question whether the same man abides, is a question of 
name, according as you understand by man either the rational 
spirit alone or the body alone of this form which is called 
human, or finally the spirit united to such a body. In the first 
case the spirit separated (at least from the coarse body) will 
be still the man ; in the second an ourang-outang, perfectly 
similar to us, reason excepted, would be a man ; and if man 
were deprived of his rational soul and received a soul of an 
animal, he would continue the same man. In the third case 
both must remain together with the union itself ; the same 
spirit, and the same body in part, or at least equivalent, as 
far as the sensible corporeal form is concerned. Thus you 
could continue the same being physically or morally, i.e. the 
same person without remaining man, in case you consider this 
figure an essential to man according to this last sense.] 

Th. [I admit that in this respect it is a question of name, 
and in the third sense the same animal is as it were now 
caterpillar or silk-worm and now butterfly, and some as it 
were have imagined that the angels of this world were men in 
a past world. But we have devoted ourselves in this confer- 
ence to discussions more important than those about the 
meaning of words. I have shown you the source of true 
physical identity ; I have made it appear that morality con- 
tradicts it no more than memory ; that they cannot always 
assign physical identity to the person indeed, whose (iden- 
tity) is at stake, nor to those who are in connection with him ; 
but that nevertheless they never contradict physical identity 
and never are completely 1 divorced from it ; that there are 
always some created spirits who know or may know what it 
is ; but that there is room to consider that what is indifferent 
regarding the persons themselves can be so only for a time.] 

1 Erdmann and Jacques omit : " entier." — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE [bk. 



CHAPTER XXVIII 

OF SOME OTHER RELATIONS, AND ESPECIALLY OP MORAL 
RELATIONS 

§ 1. Ph. Besides the relations founded upon time, space, 
and causality, of which we have just been speaking, there are 
an infinite number of others, some of which I am going to 
propose for discussion. Every simple idea capable of parts 
and of degrees, furnishes an occasion for comparing the sub- 
jects in which it is found, for example, the idea of more (or 
less or equally) white. This relation may be called propor- 
tional. 

Th. [There may be, however, excess without proportion ; 
and this is in reference to a magnitude which I call imperfect, 
as when we say that the angle which the ray makes with the 
arc of its circle is less than a right angle, for it is impossible 
that there be a proportion between these two angles, or 
between one of them and their difference, which is the angle 
of contingence.] 

§ 2. Ph. Another occasion of comparing is furnished by 
the circumstances of origin which found the relations of father 
and child, brothers, cousins, countrymen. With us people 
seldom think of saying this bull is grandfather of such a calf, 
or these two pigeons are cousins-german ; for languages are 
proportioned to use. But there are countries in which men less 
curious about their own pedigree than about that of their 
horses have not only names for each particular horse, but also 
for their different degrees of relation. 

Th. [We can furthermore join the family idea and names 
to those of relationship. It is true we do not observe under 
the empire of Charlemagne and for a sufficiently long time 
before and after family names in Germany, France, and Lom- 
bardy. It is moreover not long that there have been families 
(even noble) in the North who had no name, and in which a 
man would be recognized in his natal place only by calling his 
name and that of his father, and besides (in case he trans- 
planted himself) by joining to his own the name of the place 



CH. xxvm] ON HUMAN UNDERSTANDING 259 

whence he came. The Arabs and the Turcomans have also the 
same custom (I believe), having but few particular family 
names, and content themselves with naming the father and 
grandfather, etc., of any one, and they pay the same honor to 
their valuable horses, which they call by a proper name and 
the name of the father and even beyond. Thus they spoke of 
the horses which the Monarch 1 of the Turks sent to the 
emperor after the peace of Carlowitz ; 2 and the late count 
of Oldenburg, the last of his branch, whose studs were 
famous, and who lived a very long time, had genealogical 
trees of his horses so that he could prove their nobility, 
and went so far as to have portraits of their ancestors {imag- 
ines majorum) which were so much in demand among the 
Eomans. But to return to men, there are among the Arabs 
and the Tartars names of tribes, which are like great families, 
which are much enlarged in the course of time. And these 
names are taken either from the progenitor as in the time of 
Moses, or from the place of abode, or from some other circum- 
stance. Mr. Worsley, an observing 3 traveller, who is informed 
of the present state of Arabia Deserta, where he has been for 
some time, affirms that in all the countries between Egypt and 
Palestine, and where Moses passed, there are to-day only three 
tribes, who can bring together five thousand men, and that 
one of these tribes is called Sali from the progenitor (as I 
believe) whose tomb posterity honors as that of a saint, casting 
upon it dust which the Arabs put upon the heads of themselves 
and their camels. For the rest consanguinity exists when there 
is a common origin of those whose relation is considered; but 
we could say there is alliance or affinity between two persons, 
when they may have consanguinity with one and the same 
person without there being any for that reason between them- 
selves, which happens through the intervention of marriages. 
But as it is not customary to say that there is affinity between 
husband and wife, although their marriage may cause affinity 
in relation to other persons, it would perhaps be better to 
say that there is affinity between those who would have con- 

1 Erdmann and Jacques read : "grand Seigneur." — Te. 

2 Jan. 26, 1699. — Tr. 

3 Erdmann and Jacques read : "curieux"; Gerkardt reads: "observatif." 
— Tk. 



260 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

sanguinity between themselves if husband and wife were 
taken as one and the same person. 

§ 3. Ph. The foundation of a relation is sometimes a moral 
right, as the relation of a general of an army or of -a citizen. 
These relations depending upon the agreements men have 
made between themselves are voluntary or by institution, and 
may be distinguished from the natural. Sometimes the two 
correlatives have each its name, as patron and client, general 
and soldier. But it is not so always ; as, for example, it is not 
so in the case of those who are related to the chancellor. 

Tli. [There are sometimes natural relations which men have 
invested and enriched with certain moral relations, as, for 
example, children have the right to claim the legitimate por- 
tion of the estate of their fathers or mothers ; young persons 
are under certain restraints and the aged have certain immu- 
nities. But it also happens that some relations are taken as 
natural which are not so ; as when the laws say that the 
father is he who married the mother within the time which 
makes it possible for the child to be attributed to him ; and 
this substitution of the instituted in the place of the natural is 
sometimes only presumption, that is to say, a judgment which 
causes that to pass as true which perhaps is not so, whilst its 
falsity is not at all proved. Thus it is that the maxim : pater 
est quern nuptial demonstrant is understood in Koman law and 
among the most of the peoples where it is received. But they 
tell me that in England it avails nothing in proving his alibi; 
provided he has been in one of the three kingdoms, so that 
the presumption in that, case changes into fiction or into what 
some doctors call prcesumtio juris et de jure.~] 

§ 4. Ph. A moral relation is the conformity or disagreement 
which is found between the voluntary acts of men and a rule 
which makes us judge whether they are morally good or bad. 
§ 5. And moral good or moral evil is the^ conformity or the 
opposition which is found between voluntary acts and a cer- 
tain law which brings upon us good or evil (physical) by the 
will and power of the lawgiver (or of him who wills to main- 
tain the law) and it is this we call reward and punishment. 

Tli. [Authors, as clever as he whose views you, sir, repre- 
sent, are allowed to adapt their terms as they think proper. 
But it is also true that according to this notion one and the 






ch. xxviii] ON HUMAN UNDERSTANDING 261 

same act would be morally good and morally bad at the same 
time under different legislators, entirely as our clever author 
understood virtue above as that which is praised, and conse- 
quently the same act would be virtuous or not according to 
the opinions of men. Now that not being the ordinary sense 
that is given to morally good and virtuous acts, I prefer for 
myself, to take as the measure of moral good and of virtue 
the invariable rule of reason which God is charged with main- 
taining. We can also be assured that by his mediation all 
moral good becomes physical, 1 or as the ancients say, every 
thing virtuous is useful 2 ; while in order to express the notion 
of the author, it would be necessary to say that moral good or 
evil is an imposed or instituted good or evil, which he who has 
the power tries to make us follow or shun by punishments 
and rewards. The good is that which by the general institu- 
tion of God is conformed to nature or to reason.] 

§ 7. Ph. There are three sorts of laws: the divine law, the 
civil law, and the law of opinion or reputation. The first is 
the rule of sins or duties, the second of actions criminal or 
innocent, the third of virtues or vices. 

Th. [According to the ordinary sense of terms virtues and 
vices differ from duties and sins only as habits differ from 

i What does Leibnitz here mean by " physical " ? Possibly " physical " is 
here equivalent to "real," i.e. actual, concrete, objectively realized as distin- 
guished from that which is purely subjective and abstract, and exists in idea 
only (c/. Bk. II., chap. 27, § 9, Th. prope fin., ante, p. 247, line 7, where the two 
terms are united in one phrase " real and physical," and seem to be mutually 
interpretative and emphatic). Or, possibly, "physical" is here used in the 
sense of- "natural," the meaning of the passage being that moral good is 
realized by the mediation of God through the natural forces and in accord 
with the natural laws of the universe, which with Leibnitz have their ultimate 
source and ground in the nature of God and his choice of " the best and most 
perfect," as the universal principle of creation. The true view of the world 
is, according to Leibnitz, both physico-mechanical and moral-teleological, the 
two finding a higher unity in this principle of "the best and most perfect," 
the moral-teleological prevailing in case of collision, because of this princi- 
ple and because the physical is in its last analysis and ground spiritual and 
possessed of an inner teleological character which is realized by means of 
mechanism while resting upon the principle of the divine choice of the best. 
Cf. Discours de Metaphysique, § 19 sq., Gerhardt, 4, 444 sq. ; letter to Bayle, 
G. 3, 54; Erdmann, 106. — Tr. 

2 Cf. Cicero, De Officiis, Bk. III., chaps. 3 and 7, who shows on the author- 
ity of Pansetius and others that the virtuous and the useful — honestum and 
utile — are identical, a chief point of the Stoic philosophy. Cf. also Zeller, 
Die Philos. d. Griech., III., 1 [Vol. 5] , p. 212, 3d ed. 1880. — Tr. 



262 LEIBNITZ'S CRITIQUE OF LOCKE [ BK . n 

actions, and virtue and vice are not understood as something 
dependent upon opinion. 1 A great sin is called a crime, and 
the innoce'nt is not opposed to the criminal but to the blame- 
worthy. The divine law 2 is of two sorts, natural and positive. 
Civil law is positive. The law of reputation deserves the 
name of law only improperly, or is comprised under the 
natural law, as though I said, the law of health, the law of 
the family, when actions naturally attract some good or evil, 
as the approbation of another, health, gain.] 

§ 10. Ph. The claim is in fact everywhere made that the 
terms virtue and vice signify actions good and bad in their 
nature, and so far as they are really applied in this sense, vir- 
tue agrees perfectly with the divine (natural) law. But what- 
ever the claims of men, it is evident 3 that these names, con- 
sidered in their particular applications, are constantly and 
solely attributed to such or such actions as in each country or 
in each society are reputed honorable or shameful : otherwise 
men loould condemn themselves. Thus the measure of what is 
called virtue and vice is this approbation or this contempt, 
this esteem or this blame, which is formed by a secret or tacit 
consent. For although men united in political societies have 
resigned into the hands of the public the disposition of all 
their forces, so that they cannot employ them against their 
fellow-citizens beyond what the law permits, they nevertheless 
always retain the power of thinking well or ill, of approval 
or disapproval. 

Th. [If the clever author, who thus explains himself, should 
declare with you, sir, that it has pleased him to assign this 
present arbitrary nominal definition to the terms virtue and 
vice, we could only say that it is allowed him in theory for the 

1 Leibnitz maintains, as against Locke's theory of relativity, the absolute 
and objective character of Moral Law. It is objective and universal, not sub- 
jective and particular ; not dependent upon the opinions of men, but grounded 
in "the general institution of God," and ultimately in his infinitely perfect 
moral nature, and is thus valid for and binding upon all moral beings as such. 
This is Moral Law absolute and ideal which changes not ; it is progressively 
and approximately attained or realized in the history of the individual and 
the race according to men's apprehension of its nature and requirements and 
their strength of purpose and effort in its pursuit. — Tb. 

2 Cf. the discussion of Moral Law, in Principles and Practice of Morality, 
pp. 79 sq., by E. G. Robinson, D.D., LL.D., Ex-President of Brown University. 
Boston: Silver, Burdett & Co., 1888.— Tr. 

3 Locke has: "visible," Philos. Works, Vol. 1, p. 488 (Bohn's ed.). — Tr. 



ch. xxvin] ON HUMAN UNDERSTANDING 263 

convenience of expression for want perhaps of other terms ; but 
we shall be obliged to add that this meaning is not conformed 
to usage, nor indeed useful for edification, and that it would 
sound ill in the ears of many people, if any one should intro- 
duce it into practical life and conversation, as this author 
seems himself to admit in his preface. But it is (for us) to 
go on farther here, and although you admit that men claim to 
speak of that which is naturally virtuous or vicious according 
to immutable laws, you maintain that in fact they mean to 
speak only of that which depends on opinion. But it seems 
to me that by the same reasoning you could further maintain 
that truth and reason and all that could be named as most real, 
depends upon opinion, because men are mistaken when they 
judge of it. Is it not better then on all accounts to say, that 
men understand by virtue as by truth, that which is conformed 
to nature, but that they are mistaken often in its application ; 
besides they are mistaken less tliayi they think, for what they 
praise ordinarily deserves it in certain respects. The virtue 
of drinking, i.e. of well carrying wine, is an advantage, which 
served Bonosus, in conciliating the Barbarians and in drawing 
from them their secrets. 1 The nocturnal powers of Hercules, in 
which the same Bonosus claimed to resemble him, were no less 
a perfection. The craft of thieves was praised among the 
Spartans, and it is not the skill, but the unseasonable use 
which has been made of it, which is blamable, and those whom 
we harass in (time of) complete peace may serve sometimes as 
excellent partisans in time of war. Thus all depends upon the 
application and the good or bad use of the advantages you pos- 
sess. It is also very often true and should not be taken as a 
very strange thing, that men condemn themselves, as when they 
do what they blame in others, and there is often a contradiction 
between actions and words which scandalizes the public, when 
what a magistrate or preacher does and defends leaps to the 
eyes of the whole world.] 

§ ll. 2 Ph. Everywhere that which passes as virtue is that 
which is thought worthy of praise. Virtue and praise are often 
designated by the same name. Sunt hie etiam sua prwmia 
laudi, says Vergil (Aen. I. 461) and Cicero, Nihil habet natura 

1 Of. Vopiscus, Script, hist. August., Vol. 2, pp. 213, 214, ed. Peter. — Tr. 

2 Gerhardt and Locke; Erdmann and Jacques have § 12. —Tr. 



264 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

praestantius quam honestatem, quam laudem, quam dignitatem, 
quam decks. 1 (Qucest. Tuscul. Bk. 2. chap. 20) and he adds 
a little after : Hisce ego pluribus nominibus unam rem declarari 
volo. 1 

Th. [It is true that the ancients have designated virtue by 
the name honesty (Vhonneste), as when they have praised in- 
coctum generoso pectus honesto. 2 It is true also that honesty 
(Vhonneste) has its name of honor or of praise. But this 
means not that virtue is that which is praised but that it is 
that which is worthy of praise and which depends upon truth, 
and not upon opinion.] 

Ph. Many do not think at all seriously of the law of God, or 
hope that they will one day be reconciled with its author, and 
as regards the law of the state they flatter themselves with im- 
punity. But they do not think that he who does anything 
contrary to the opinions of those with whom he associates, and 
to whom he wishes to commend himself, can avoid the pain of 
their censure and of their disdain. No one who retains any 
consciousness of his own nature can live in society constantly 
despised ; this is the force of the law of reputation. 

Th. [I have already said that it is not so much the pain of a 
law, as a natural pain which the act draws upon itself. It is, 
however, true that many people are but little concerned about 
it, because ordinarily, if they are despised by some on account 
of some blameworthy act, they find accomplices or at least 
partisans, who do not despise them, if they are ever so little 
commendable in some other respect. They forget even acts 
the most infamous, and it often suffices to be bold and im- 
pudent like that Phormio of Terence in order that all may be 
overlooked. If excommunication produced a truly constant 
and general contempt, it would have the force of this law of 
which our author speaks : and it had in fact this force with the 
first Christians and for them took the place of the right, which 
they lacked, to punish the guilty ; nearly as artisans maintain 
certain customs among themselves in spite of the laws, through 

1 The quotation is not exact. Cf. op. cit., ed. Klotz, Lipsise, B. G. Teub- 
ner, 1870, where the text reads thus: "Nihil euim habet praestantius, nihil 
quod niagis expetat quam honestatem, quam laudem, quam dignitatem, quam 
decus. Hisce ego pluribus nominibus unam rem declarari volo, sed utor, ut 
quam maxime significem, pluribus." — Tb. 

2 Persius. Sat. 2, 74. — Tb. 



ch. xxix] ON HUMAN UNDERSTANDING 265 

the contempt which they show for those who do not observe 
them. And it is this which has also maintained duels con- 
trary to the ordinances. It would be desirable for the public 
to agree with its.elf and with reason in its praise and blame ; 
and that the great above all do not encourage the bad by laugh- 
ing at their bad actions, in which it oftenest seems that not he 
who has done them, but he who has suffered them is punished 
by contempt and ridiculed. We shall see also generally that 
men despise not so much vice as weakness and misfortune. 
Thus the law of reputation would need to be greatly reformed, 
and also to be better observed.] 

§ 19. Ph. Before leaving the consideration of relations, I 
would remark that we usually have a notion as clear or clearer 
of the relation than of its ground. If I believed that Sempronia 
took Titus from beneath a cabbage, as they used to tell little 
children, and that afterwards she had had Caius in the same 
manner, I should have as clear a notion of the relation of 
brother between Titus and Caius, as if I had all the knowledge 
of the miclwives. 

Th. But when they once said to a child, that his little 
brother, who had just been born, had been drawn from a well 
(a reply which they make use of in Germany to satisfy the 
curiosity of children upon this subject) the child replied that 
he wondered that they did not throw him back again into the 
same well when he cried so much and disturbed his mother. 
The fact is this explanation did not make him know any rea- 
son for the love his mother showed for the child. We can say 
then that those who do not know the ground of relations have 
only concerning them what I call thoughts, surd in part and 
insufficient, although these thoughts may suffice in certain 
respects and upon certain occasions.] 



CHAPTEB XXIX 

OF CLEAR AND OBSCURE, DISTINCT AND CONFUSED IDEAS 

§ 2. Ph. We come now to some differences of ideas. Our 
simple ideas are clear when they are such as the objects them- 
selves, from whence they are received, represent or may 



266 LEIBNITZ'S CRITIQUE OF LOCKE [bk. h 

represent them with all the circumstances requisite to a well- 
ordered sensation or perception. While the memory retains 
them in this way, they are in this case clear ideas, and so far 
as they lack this original exactness or have lost anything so 
to speak of their first freshness, and are, as it were, tarnished 
or faded by time, so far are they obscure. Complex ideas are 
clear, when the simple ideas which compose them are clear and 
the number and order of these simple ideas are fixed. 

Th. [In a brief discourse on ideas, 1 true or false, clear or 
obscure, distinct or confused, inserted in the " Leipsic Acts " 
of the year 1684, I have given a definition of clear ideas, 
common to the simple and complex and which gives the rea- 
son of what you say here. I said then that an idea is clear 
when it suffices to recognize and distinguish the thing: as 
when I have a very clear idea of a color, I shall not take 
another instead of that which I ask for, and if I have a clear 
idea of a plant, I shall distinguish it among other neighboring 
ones ; without this the idea is obscure. I believe that we have 
but few perfectly clear ideas of sensible things. There are 
colors which approach each other in such a way that we can- 
not distinguish them by memory, and yet we will sometimes 
distinguish them by placing one near the other. And when 
we think we have fully described a plant, we can bring one 
from the Indies which will have all we have put into our 
description and which will not cease making itself known as 
a different species : thus we can never perfectly determine 
species infamce, or the lowest species.] 

§ 4. Ph. As a clear idea is that whereof the mind has such 
a full and evident perception as it receives from an external 
object operating duly upon a well-disposed organ ; so a distinct 
idea is that wherein the mind perceives a difference, which 
distinguishes it from every other idea ; and a confused idea is 
that which cannot be sufficiently distinguished from another 
from which it should be different. 

Th. [According to this notion which you give of the dis- 
tinct idea, I do not see how you distinguish it from the clear 
idea. This is why I have been wont to follow here the lan- 
guage of Descartes, with whom an idea may be clear and con- 

1 Meditationes de Cognitione, Veritate et Ideis. Cf. ante, p. 14, note 2; 
p. 227, note 3. — Tr. 



en. xxix] ON HUMAN UNDERSTANDING 267 

fused at the same time ; and such are the ideas of sensible 
qualities, appropriate to the organs, such as color or heat. They 
are clear, for they are easily recognized and distinguished the 
one from the other, but they are not distinct, because they are 
not distinguished by what they include. Thus we cannot give 
a definition of them. We make them known only by examples, 
and for the rest we must say it is an indefinite somewhat, 
until we can decipher its contexture. Thus although in 
our view distinct ideas distinguish one object from another ; 
nevertheless, as the ideas clear, but confused in themselves, do 
so also, we call distinct not all those which are very discrimi- 
nating or which distinguish objects, but those which are well 
distinguished, i.e. which are distinct in themselves and dis- 
tinguish in the object the marks which make it known, which 
an analysis or definition of it gives ; otherwise we call them 
confused. And in this sense the confusion which reigns in 
ideas can be exempt from blame, being an imperfection of our 
nature ; for we cannot discern the causes, for example, of odors 
and tastes, nor the content of these qualities. This confusion 
can, however, be blameworthy, when it is important and 
within my power to have distinct ideas, as, for example, if I 
took adulterated gold as the true, for want of making the 
necessary assays which contain the marks of good gold. 

§ 5. Ph. But you will say that there is no idea confused (or 
rather according to your view, obscure) in itself 1 for it can be 
only such as it is perceived by the mind, and that distin- 
guishes it sufficiently from all others. § 6. And in order to 
remove this difficulty it is needful to know that the defect of 
ideas is related to names, and what renders it faulty is the 
fact that it can as well be designated by another name as the 
one which we use to express it. 

Th. [It seems to me that we ought not to make this depend 
upon names. Alexander the Great had seen (they say) in a 
dream a plant able to cure Lysimachus, which has since 
been called Lysimachia, because it effectually cured this friend 
of the king. When Alexander had a quantity of plants 
brought, among which he recognized that which he had seen 
in his dream, if unfortunately he had not had a sufficient idea 
of it to recognize it and had needed as Nebuchadnezzar a 
1 Erdniann and Jacques omit: " en elle meaie." — Ik,. 



268 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

Daniel to enable him to recall his dream, it is plain that the 
idea he would have had of it would have been obscure and 
imperfect (for it is thus I should prefer to call it rather than 
confused), not for want of appositeness in a certain name, for 
there was none, but for want of application to the thing, i.e. 
to the plant which was to heal. In this case Alexander would 
be reminded of certain circumstances, but he would have been 
in doubt about others ; and the name serving us to designate 
anything makes us, when we fail in the application to names, 
fail ordinarily in regard to the thing which is promised by 
this name.] 

§ 7. Ph. As complex ideas are the most subject to this 
imperfection, it may arise from the fact that the idea is 
composed of too small a number of simple ideas, as is, for 
example, the idea of an animal which has the skin spotted, (a 
term) which is too general, and which does not suffice to dis- 
tinguish the lynx, the leopard, or the panther, which are 
besides distinguished by particular names. 

Th. [If we were in the condition Adam was in before he 
had given names to the animals, this defect would not cease 
to have place. For supposing we knew that among the 
spotted animals there is one which has extraordinarily pene- 
trating sight, but that we did not know whether it is a tiger 
or a lynx, or some other species ; it is an imperfection not 
to be able to distinguish it. Thus the question is not so 
much about the name as about that which may give occa- 
sion for it, and which renders the animal worthy of a particu- 
lar name. It thereby appears also that the idea of a spotted 
animal is good in itself, and without confusion and obscurity, 
when it is to serve only the genus ; but when joined with 
some other idea which is not sufficiently remembered it is 
to designate the species, the complex idea is obscure and 
imperfect.] 

§ 8. Ph. There is an opposite defect when the simple ideas 
which make up the complex idea are sufficient in number, but 
too confused and involved, like some pictures, which appear 
so confused that they must be only the representation of the 
sky covered with clouds, in which case also we could not say 
that there is confusion any more than if it were another pic- 
ture made to imitate that one ; but when we say that this 



ch. xxix] ON HUMAN UNDERSTANDING 269 

picture should make us see a portrait, we shall haye reason 
to say that it is confused because we cannot say whether 
it is that of a man, or of a moukey, or of a fish, but it may be 
that when we look at it in a cylindrical mirror, the confusion 
will disappear, and that we shall see that it is a Julius Caesar. 
Thus some mental paintings (if I may so express myself) can- 
not be called confused from any way in which the parts are 
joined together ; for whatever these paintings are, they can 
obviously be distinguished from every other, until they are 
ranked under some ordinary name, to which we cannot see 
that they belong any more than to some other name of a 
different signification. 

Th. [This picture whose parts we see distinctly, without 
noticing the result to which they in a certain way point, 
resembles the idea of a heap of stones, which is truly confused 
not only in your sense, but also in mine, so far as we have 
distinctly conceived their number and other properties. If 
there were thirty-six of them (for example), we would not 
know, looking at them heaped together without arrangement, 
that they may produce a triangle or indeed a square, as in 
fact they can, because thirty-six is a square as well as a tri- 
angular number. Thus it is that, in looking at a figure of a 
thousand sides, we shall have only a confused idea of it, until 
we know the number of the sides which is the cube of ten. 
The question, then, is not of names but of the distinct proper- 
ties which are to be found in the idea when we have cleared 
up its confusion. And it is sometimes difficult to find the 
key, or the manner of looking at it from a certain point, either 
by the intervention of a certain mirror or glass in order to see 
the purpose of him who has caused the thing.] 

§ 9. Ph. It cannot be denied that there is yet a third defect 
in ideas, which depends in truth upon the bad use of names ; 
it is when our ideas are uncertain or undetermined. Thus 
we may see every day men who, making no difficulty of 
availing themselves of the ordinary words of their mother 
tongue, before they have learned their precise meaning, change 
the idea which they attach to them almost as often as they 
use them in their discourse. § 10. Thus we see how much 
names contribute to this denomination of ideas distinct and 
confused, and, without the consideration of distinct names 



270 LEIBNITZ'S CRITIQUE OE LOCKE [bk. ii 

understood as signs of distinct things, it will be very difficult 
to say what a confused idea is. 

Til. [I have, however, just explained it without considering 
the names, whether in the case where the confusion is under- 
stood with you as what I call obscurity, or in that where it is 
understood in my sense as the defect in the analysis of the 
notion we have. And I have also shown that every obscure 
idea is in fact indeterminate or uncertain, as in the example 
of the spotted animal we have seen, where we know that some- 
thing further must be added to this general notion, without 
clearly remembering it ; so that the first and third defect 
which you have specified come to the same thing. It is, how- 
ever, very true that the abuse of words is a great source 
of errors, for a kind of error in calculating occurs therefrom, 
as if in calculating we did not notice carefully the place of 
the counter, or if we wrote the figures so badly that we could 
not distinguish a 2 from a 7, or if we omitted or changed 
them through inadvertence. This abuse of words consists 
either in not connecting ideas with the whole or in connecting 
them with an imperfect one, of which a part is empty and 
abides so to speak in blank ; and in these two cases there is a 
certain void and surd in the thought which is filled only 
by the name. Or, finally, the defect is in attaching to the 
word different ideas, whether we are uncertain which should 
be chosen, which makes the idea obscure as well as when a 
part of it is surd ; or whether we select them by turns, and 
avail ourselves sometimes of one, sometimes of the other as 
the sense of the same word in one and the same course of 
reasoning in a way capable of causing error, without consider- 
ing that the ideas do not agree. Thus the uncertain thought 
is either void and without idea, or fluctuates between several 
ideas. This does harm whether 1 we wish to designate some 
definite thing or whether we wish to give a word a certain 
sense corresponding either to that of which we have already 
availed ourselves, or to that which others have used, above 
all in ordinary language, common to all, or to the artisans. 
And from this arise an infinite number of vague and vain dis- 
putes in conversation, in lecture-rooms, and in books, which we 

1 Erdmann and Jacques omit: " soit qu'on veuille designer quelque chose 
determined, " the reading of Gerhardt. — Tr. 



ch. xxix] ON HUMAN UNDEKSTANDING 271 

may sometimes avoid by distinctions, but which most fre- 
quently serve only to confuse the more, by putting in the 
place of a vague and obscure term other terms still more 
vague and obscure, as those often are which the philosophers 
employ in their distinctions, without having good definitions 
of them.] 

§ 12. Ph. If there is any other confusion in ideas, than this 
which has a secret relation to names, this at least casts more 
disorder than any other into the thoughts and discourse of 
men. 

Th. [I agree, but most frequently some notion of the thing 
and the purpose which we have in availing ourselves of 
the name is mixed with it ; as, for example, when Ave speak 
of the church, many have in view a government, while others 
think of the truth of the doctrine.] 

Ph. The way to prevent this confusion is constantly to 
apply the same name to a certain mass of simple ideas united 
in a fixed number and into a determined order. But as that 
suits neither the laziness nor the vanity of men, and as it can 
be used only in the discovery and the defence of the truth, 
which is not always the end they propose to themselves, such 
precision is one of the things that is rather to be wished than 
hoped for. The vague application of names to ideas inde- 
terminate, variable, and almost wholly empty (in the surd 
thoughts) is on one side a covering of our ignorance and 
on the other a confusing and embarrassing of others, which 
passes as true learning and as a mark of superiority in point 
of knowledge. 

Tli. [The affectation of elegance and wit has further con- 
tributed much to this intricacy of language ; for in order to 
express thoughts beautifully and agreeably we make no diffi- 
culty of giving words in a tropical manner a sense different 
from the ordinary, sometimes more general or more limited, 
which is called synecdoche, sometimes transferred according to 
the relations of things whose names we change, either by 
concurrence in metonymy, or by comparison in metaphor, not 
to speak of irony, which makes use of a term in a sense 
directly opposite to its real meaning. Thus these changes are 
named when recognized ; but they are recognized only rarely. 
And in this indeterminateness of language, in which there is 



272 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

lacking a kind of law which regulates the meaning of words, 
as there is something in the title of the digests of the Koman 
Law, De Verborum Significationibits, persons the most judic- 
ious, when they write for ordinary readers, would be deprived 
of that which gives charm and force to their expression if 
they should confine themselves rigorously to the fixed mean- 
ings of terms. They need only take care that their variation 
does not cause any error or false reasoning to spring up. The 
distinction of the ancients between the exoteric, 1 i.e. popular, 
and the acroamatic 1 mode of writing, which belongs to those 
who are occupied in the discovery of truth, has place here. 
And if any one wished to write in mathematical fashion in 
metaphysics or ethics, nothing would prevent him from so 
doing with rigor. Some have professed to do this, and we 
have a promise of mathematical demonstrations outside of 
mathematics ; but it is very rare that they have been success- 
ful. This is, I believe, because they are disgusted with the 
trouble it is necessary to take for a small number of readers 
where they could ask as in Persius : Quis leget haec, and 
reply : Vel duo vel nemo. 2 I believe, however, that if they 
would undertake it in the proper way they would not be 
likely to repent it. And I have been tempted to try it.] 

§ 13. Ph. You will agree with me, however, that complex 
ideas may be very clear and distinct in one aspect, and very 
obscure and confused in another. 

Th. [There is no reason to doubt it ; for example, we have 
very distinct ideas of a good part of the solid visible parts 
of the human body, but we have but few of the liquids which 
enter therein.] 

Ph. If a man speaks of a figure of a thousand sides, the 

1 Of. Leibnitz, De Stilo philos. Nizolii, Gerhardt, Vol. 4, p. 146; Erdmann, 
p. 63. " Acroamatic" {ante, p. 42), from d/cpdap-a, anything heard", the verb 
aKpoao-Oai, the regular word for hearing or attending lectures, the adjective 
a.Kpoa.jaa.TiKds, designed for hearing only, and, when used of the doctrines of 
philosophers, meaning the esoteric, i.e. the doctrines in their most rigorous 
and exact scientific form, their custom being to give these orally to their 
pupils, while treating them in a more popular, exoteric manner in their writ- 
ings. Such was the method of Plato and of Aristotle, one of whose works is 
called <f>vo-i/<r) dicpdao-i?. Schaarschmidt refers to Bernays, Die Dialogs d. Aris- 
totles, p. 30 sq. Berlin, 1863, and Madvig, Excursus VII. to his edition of 
Cicero's De Finibus. — Tr. 

2 Sat. 1, lines 2, 3. — Tr. 



ch. xxix] ON HUMAN UNDEESTANDING 273 

idea of this figure may be very obscure in his mind, although 
that of the number may be very distinct therein. 

Th. [This example is not in point here ; a regular polygon 
of a thousand sides is known as distinctly as the millenary 
number, because we may discover and demonstrate all kinds 
of truth.] 

Ph. But we do not have a precise idea of a figure of 
a thousand sides, so that we can distinguish it from another, 
which has only nine hundred ninety-nine. 

Th. [This example shows that you here confound the idea 
with the image. If any one places before me a regular poly- 
gon, sight and imagination cannot make me comprehend the 
millenary therein ; I have only a confused idea both of the 
figure and of its number, until I distinguish the number by 
counting. But having found it, I know very well the nature 
and the properties of the proposed polygon, as far as they 
are those of the chiliagon, and consequently I have this idea 
of it ; but I cannot have the image of a chiliagon, and it would 
be necessary to have senses and imagination more exquisite 
and better exercised in order to distinguish it thereby from 
a polygon which had one side less. But the knowledge of 
figures no more than that of numbers depends upon the imag- 
ination, although it is of service therein ; and a mathematician 
can know exactly the nature of a nonagon and a decagon, 
because he has the means of making and examining them, 
though he could not discern them at sight. It is true that a 
workman or an engineer, who does not perhaps know their 
nature sufficiently, can have this advantage beyond a great 
geometer that he can discern them by sight only without 
measuring them, as there are some street-porters * (faquins) or 
pedlers, who will state the weight of what they are to carry 
within a pound, in which respect they will surpass the most 
skilful statistician in the world. It is true that 2 this empiri- 
cal knowledge acquired by a long practice may be very useful 
for prompt action, such as an engineer very often needs to 
perform because of the danger to which he is exposed in 
delaying. But this clear image or this feeling which we may 

1 Erdrnann and Jacques omit: " faquins ou," the reading of Gerhardt. — Tb. 

2 Erdrnann and Jacques omit: " D est vray que," the reading of Gerhardt. 
— Tr. 



274 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

have of a regular decagon or of a weight of ninety-nine pounds 
consists only in a confused idea, since it is of no avail in dis- 
covering the nature and properties of this weight or of this 
regular decagon, which demands a distinct idea. And this 
example conduces to the better understanding of the differ- 
ence of ideas, or rather that of the idea and the image.] 

§ 15. 1 Ph. Another example : We are led to believe that we 
have a positive and complete idea of eternity, which is as 
much as to say that there is no part of that duration which 
is not clearly known in our idea ; but, however great may be 
the duration that is represented, as it is a question of an 
extension without limits, there always remains a part of the 
idea beyond what is represented which continues obscure and 
undetermined; and thence it comes that, in discussions and 
reasonings concerning eternity or any other infinite, we are 
apt to involve ourselves in manifest absurdities. 

Th. [This example does not appear to me to square with 
your design either ; but it is very appropriate to mine, which 
is to disabuse you of your notions on this point. For 
the same confusion of the image with the idea reigns here. 
We have a complete or just idea of eternity, since we have a 
definition of it, although we have no image of it. But the 
idea of the infinite is not formed by the composition of parts, 
and the errors which we meet in reasoning upon the infinite 
do not arise from the defect of the image. 2 ] 

§ 16. 3 Ph. But is it not true that when we speak of the 
infinite divisibility of matter, although we have clear ideas of 
the division, we have only very obscure and very confused 
ideas of the parts ? For I ask whether a man taking the 

1 Erdmann and Jacques have § 25. Gerhardt and Locke, Philos. Works, 
Vol. 1, p. 505 (Bonn's ed.), have § 15.— Tb. 

2 The difficulties and errors in the discussion of the infinite arise not " from 
the defect of the image" hut from the attempt to imagine or picture that 
which can only he thought. We can think the infinite and absolute, hut we 
cannot form an adequate image or picture of it. The " confusion of the image 
with the idea," which Leibnitz here speaks of, is one of the causes vitiating 

■ much of the "reasoning upon the infinite" in the history of thought, and 
lying at the basis of all theories, like those of Hamilton, Mansel, and Spencer, 
which maintain the impossibility on man's part of a knowledge of the infinite. 
Of. John Caird, An Introduction to the Philos. of Religion, p. 36. New York : 
Macmillan & Co., 1880. — Tb. 

3 So Gerhardt and Locke, Philos. Works (Bohn's ed.), Vol. 1, p. 505 ; Erd- 
mann has § 18; Jacques § 30. — Tb. 



ch. xxx] ON HUMAN UNDERSTANDING 275 

smallest atom of dust he ever saw has any distinct idea 
of the difference between the one hundred thousandth 1 and 
the millionth part of this atom ? 

Th. It is the same qui pro quo of the image for the idea, 
which I am astonished to see so confused. The possession of 
an image of so great a smallness is not at all the question. 
It is impossible according to the present constitution of 
our body, and if we could have it, it would be much the same 
as that of those things which now appear to us apperceptible ; 
but in compensation what is now the object of our imagination 
would escape us and become too great to be imagined. Size 
has no images in itself, and those which it has depend only 
upon comparison with the organs and other objects, and it is 
.useless here to employ imagination. Thus it appears by all 
that you, sir, have said to me here that you are ingenious 
in devising difficulties without reason, in demanding more 
than is necessary.] 



CHAPTEE XXX 

OP REAL AND FANTASTICAL IDEAS 

§ 1. Ph. Ideas in relation to things are real or fantastical, 
adequate or inadequate, true or false. By real ideas I under- 
stand those which have a foundation in nature, and which are 
conformed to a real being, to the existence of things, or to 
their archetypes ; otherwise they are fantastic or chimerical. 

Th. [There is a little obscurity in this explication. The 
idea may have a foundation in nature, without being con- 
formed to this foundation, as when we maintain that the per- 
ceptions we have of color and heat do not resemble any orig- 
inal or archetype. An idea is also real when it is possible, 
although no existing being corresponds thereto. Otherwise 
if all the individuals of a species were lost, the idea of the 
species would become chimerical.] 

§ 2. Ph. Simple ideas are all real, for, although [according 
to many] whiteness and coldness are no more in snow than is 
pain, yet their ideas are in us as effects of powers connected 
1 Erdmann and Jacques read : " la 10,000ine et la lOOOnie." — Tr. 



276 LEIBNITZ'S CKITIQUE OF LOCKE [bk. ii 

with external things, and these constant effects serve us in 
distinguishing things as much as if they were exact images of 
that which exists in the things themselves. 

Th. [I have examined this point above : but it appears 
thereby that you do not always demand a conformity to an 
archetype, and, according to the opinion (which, however, I do 
not approve) of those who think that God has arbitrarily 
assigned us ideas, destined to mark the qualities of objects 
without any resemblance or even natural relation, there would 
be also in that case less conformity between our ideas and 
the archetypes than there is between the words which we use 
by institution in language and the ideas, or the things them- 
selves. ] 

§ 3. Ph. The mind is passive as regards its simple ideas; 
but the combinations it makes of them to form complex ideas, 
where many simple ideas are comprised under one and the 
same name, have somewhat of the volitional element ; for one 
man admits into the complex ideas he has of gold or of 
justice simple ideas which another does not admit. 

Th. [The mind is, however, active in reference to simple 
ideas when it detaches them one from another to consider 
them separately, — an act which is voluntary as well as the 
combination of many ideas ; whether it is done to call atten- 
tion to a complex idea resulting therein, or whether it is the 
purpose to comprehend them under the name given to the 
combination. And the mind cannot be deceived therein pro- 
vided it does not unite incompatible ideas and provided this 
name is still virginal, so to speak, that is to say, a name to 
which some notion has not already been attached, which might 
cause confusion with that which is newly attached thereto, and 
make arise either impossible notions by joining together what 
cannot take place, or notions superfluous and containing some 
obreption, 1 by joining ideas, one of which may and ought to 
be derived from the other by demonstration.] 

§ 4. Ph. Mixed modes and relations having no other reality 
than that which they have in men's minds, all that is requisite 
to make these sorts of ideas real is the possibility of existence 
or of compatibility together. 

Th. [Relations have a reality dependent upon the mind 
1 I.e. Concealment of the truth. — Tk. 



ch. xxx] ON HUMAN UNDERSTANDING 277 

like truths; but not the mind of men, since there is a supreme 
intelligence which determines them all for all time. Mixed 
modes, which are distinct from relations, may be real acci- 
dents. But be they dependent or not dependent upon the 
mind, it suffices for the reality of their ideas that these modes 
be possible or, what is the same thing, distinctly intelligible. 
And for this result it is necessary that their ingredients be 
comjjossible, i.e. capable of existing together.] 

§ 5. Ph. But the complex ideas of substances, as they are 
all formed in relation to things existing outside of us, and 
as representative of substances such as really exist, are real 
only so far as they are combinations of simple ideas really 
both united and coexisting in things coexisting without us. 
On the contrary those are chimerical 1 which are composed of 
such collections of simple ideas as have never been really 
united and found together in any substance ; like those which 
form a centaur, a body resembling gold, save in weight, and 
lighter than water, a body similar in relation to the senses, 
but endowed with perception, voluntary movement, etc. 

Th. [If I take in this manner the terms real and chimeri- 
cal otherwise in relation to the ideas of the modes than in 
relation to those which form a substance, I do not see what 
common notion in each case you give to real or chimerical 
ideas ; for the modes are real to you when they are possible, 
and substances have real ideas with you only when they 
are existent. But in desiring to tally with existence, we 
can determine but little whether an idea is chimerical or 
not, because what is possible, although not found in our 
place or time, may have existed formerly or will perhaps 
some day exist, or may indeed be found already present in 
another world, or even in ours without our knowing it, like 
the idea which Democritus had of the Milky Way 2 which the 
telescopes have verified : so that it seems better to say that 
possible ideas only become chimerical when we attach to them 
without foundation the idea of effective existence, as those do 
who promise themselves the philosopher's stone or, as those 

1 Locke has: "fantastical," Philos. Works, Vol. 1, p. 510 (Bonn's ed.). — 
Tk. 

2 Of. Aristotle, Meteorologica, Bk. I., chap. 8, 345*, 25: "The Milky Way 
is the light of certain stars." Zeller, Die Philos. d. Griech., 3d ed., Vol. 1, 
p. 724, note 1 ; 5th ed., 1892, 1. 2 [Vol. 2] , p. 897, note 8. — Tr. 



278 LEIBNITZ'S CEITIQUB OF LOCKE [bk. ii 

would do who should believe that there had been a nation 
of centaurs. Otherwise in not regulating ourselves by exist- 
ence we shall deviate unnecessarily from the received language, 
which does not allow us to say that he who speaks in winter 
of roses or pinks speaks of a chimera, unless he imagines he is 
able to find them in his garden, as the story is told of Albert 
the Great 1 or of some other pretended Magician.] 



CHAPTER XXXI 

OF ADEQUATE 2 AND INADEQUATE IDEAS 

§ 1. Ph. Real ideas are complete when they represent per- 
fectly the originals whence the mind supposes them to be 
taken, which they represent, and to which it refers them. 
Incomplete ideas represent only a part of these originals. 
§ 2. All our simple ideas- are complete. The idea of white- 
ness or of sweetness, which is noticed in sugar, is complete, 
because it suffices for this, — that it corresponds entirely to the 
powers that God has put into this body to produce these 
sensations. 

Tli. [I see, sir, that you call complete or incomplete ideas 
those which your favorite author calls idem adcequataz aut 
inadcequatw ; you might call them perfect or imperfect. I 
have sometimes defined idea adazquata (a perfect idea) as that 
which is so distinct that all its ingredients are distinct, and 
such is nearly the idea of a number. But when an idea is 
distinct and contains the definition or the reciprocal marks 
of the object, it may be inadazquata or imperfect, viz. : when 

1 Albertus Magnus, 1193-1280. Schaarschmidt states that " like many other 
scholars of those dark centuries (Michael Scotus, Roger Bacon, etc.) he was 
suspected of Magic," and adds that " Trithemius in particular, who, moreover, 
takes the philosopher into his protection, gives an account thereof in his An- 
nates Hirsaugienses, Vol. 2, p. 40. Naude in his Apologia des Grands Hommes 
Soupconne's de Magie, chap. 18, Bayle in his Dictionary, see under Albert 
Le Grand, and Brucker, Hist. Philosophise, 3, 793 sq., have likewise defended 
him." On his life and philosophy, cf. Erdmann, Orundriss d. Gesch. d. 
Philos. §§ 199-202, Vol. 1, pp. 356 sq., and English translation of same ; also 
Stockl, Gesch. d. Philos. d. Mittelalters, VoL 2, pp. 352 sq., §§ 101-119. — Tr. 

2 Locke's title; the French might he rendered " complete and incomplete," 
as in the text. — Tr. 



ch. xxxi] ON HUMAN UNDERSTANDING 279 

these marks or these ingredients are not also all distinctly 
known; for example, gold is a metal which resists the cupel 
and aqua fortis ; it is a distinct idea, for it gives the marks 
or the definition of gold; but it is not perfect for the nature 
of cupellation and the working of aqua fortis is not sufficiently 
known to us. Whence it comes that, when there is only an 
imperfect idea, the same subject is susceptible of many defini- 
tions independent the one of the other, so that we cannot 
always derive one from the other nor see beforehand that they 
must belong to one and the same subject, and then experience 
alone teaches us that they all belong to it at once. Thus gold 
may still be defined as the heaviest of our bodies, or the most 
malleable, without speaking of other definitions which might 
be invented. But we shall be able to see why it belongs 
to the heaviest of metals to resist these two tests of the assay- 
ers only when men shall have penetrated farther into the 
nature of things ; whilst in geometry, where we have perfect 
ideas, the case is different, for we can prove that the sec- 
tions of the cone and of the cylinder, made by a plane, are the 
same, viz. ellipses, and this cannot be unknown to us, if we 
take notice of it, because the notions we have of them are 
perfect. 'With me the division of ideas into perfect and im- 
perfect is only a sub-division of distinct ideas, a&d it appears 
to me that only the confused ideas, like that we have of sweet- 
ness, of which you, sir, speak, deserve this name ; for although 
they express the power which produces the sensation, they 
do not express it wholly, or at least we cannot know this, for 
if Ave comprehended what is in this idea of sweetness we have 
"we could judge whether it is sufficient as a rational expression 
of all that experience causes us to notice therein.] 

§ 3. Ph. From simple ideas let us come to the complex; 
they are either of modes or of substances. Those of modes 
are the voluntary collections of simple ideas which the mind 
puts together without regard to certain archetypes or real and 
actually existing models ; they are complete and cannot be 
otherwise, because not being copies but archetypes, which the 
mind forms in order to avail itself of them in ranking things 
under certain denominations, they can lack nothing, because 
each includes such a combination of ideas as the mind has 
desired to form, and consequently such perfection as it had 



280 LEIBNITZ'S CEITIQUE OF LOCKE [bk. 11 

planned to give thereto, and we cannot conceive that the 
understanding of any one can have a more complete or more 
perfect idea of a triangle than that of a figure of three sides 
and three angles. He who put together the ideas of danger, 
of execution, of the trouble that fear produces, of a calm con- 
sideration of what it would be reasonable to do, and of an 
actual application to its execution without being frightened 
by the danger, formed the idea of courage, and had what he 
desired, viz. : a complete idea conformed to his good pleasure. 
It is otherwise in our ideas of substances in which we main- 
tain that which really exists. 

Th. [The idea of triangle or of courage has its archetype in 
the possibility of things as well as the idea of gold. And it is 
a matter of indifference, so far as the nature of the idea 
is concerned, whether it was invented in advance of experi- 
ence, or whether it was retained after the perception of a 
combination which nature had made. Combination also, 
which produces the modes, is not wholly voluntary or arbi- 
trary, for we can put together what is incompatible, as those 
do who invent machines for perpetual motion, while others 
can invent those which are good and practicable which have 
no other archetypes with us than the idea of the inventor 
which has as its archetype the possibility of things or the 
divine idea. Now these machines are substances. We can 
also invent impossible modes, as when we maintain the 
parallelism of parabolas, by imagining that we can find two 
parabolas parallel to each other, like two straight lines or 
two circles. An idea, then, whether it be that of a mode, or 
that of a substance, may be complete or incomplete according 
as we understand well or ill the partial ideas which form the 
total idea : and it is a mark of a perfect idea when it makes 
known perfectly the possibility of the object.] 



ch. xxxin] ON HUMAN UNDERSTANDING 281 



CHAPTER XXXII 

OF TRUE AND FALSE IDEAS 

§ 1. Ph. As truth 1 or falsehood belongs only to proposi- 
tions, 2 it follows that when ideas are termed true or false 
there is some tacit proposition or affirmation ; § 3. or a tacit 
assumption of their conformity to something, § 5. above all 
with what others designate by this name (as when they speak 
of justice) item to what really exists (as man exists but not 
the centaur) item to the essence, upon which depend the prop- 
erties of the thing ; and in this sense our ordinary ideas of 
substances are false when we think of certain substantial 
forms. Besides, ideas deserve rather to be called accurate 
or faulty, than true or false. 

Th. I believe that true or false ideas might be so under- 
stood, but as these different senses do not agree between them- 
selves and cannot be conveniently ranked under a common 
notion, I prefer to call the ideas true or false in relation to 
another tacit affirmation which they all include, which is that 
of possibility. Thus possible ideas are true, impossible false.'] 



CHAPTER XXXIII 

OF THE ASSOCIATION OF IDEAS 

§ 1. Ph. We often notice something odd in the reasonings 
of people, and everybody is subject to this. § 2. It is not 
alone obstinacy or self-love ; for often people who are well 
disposed are guilty of this fault. It does not indeed suffice to 

1 Of. New Essays, Bk. IV., chap. 5. — Tr. 

2 Of. Aristotle De Anima, III. 6,430 a , 27, and E. Wallace, Aristotle's Psychol- 
ogy in Greek and English, with Introduction and Notes, pp. 160, 161, Cam- 
bridge: University Press, 1882; also De Interpret. 1, 16 a , 12, and E. Wallace, 
Outlines of the Philos. of Aristotle, 3d ed., § 11, p. 27. For Leibnitz, the trne 
is the thinkable, i.e. that which is free from contradiction in itself and of 
other truth. Thought-necessity is his criterion of possibility and of truth. — 



282 LEIBNITZ'S CRITIQUE OF LOCKE [bk. 11 

attribute it to education and to prejudice. § 4. It is rather 
a kind of madness, and we should be foolish if we should 
always act thus. § 5. This fault arises from a non-natural 
connection of ideas, which has its origin in chance or custom. 
§ 6. Inclination and interest enter into it. Certain tracts of 
the repeated course of animal spirits become beaten roads ; 
when we know 1 a certain air, we find it as soon as we begin 
it. § 7. Thence arise the sympathies or antipathies which 
are not born with us. A child has eaten too much honey and 
has been surfeited by it, and then having become a full-grown 
man, he cannot hear the name honey without a rising of the 
stomach. § 8. Children are very susceptible to these impres- 
sions, and it is well to be careful of them. § 9. This irregu- 
lar association of ideas has a great influence in all our actions 
and passions natural and moral. § 10. Darkness revives the 
idea of ghosts in children because of the stories told them 
about them. § 11. You do not think of a man whom yon 
hate without thinking of the evil he has done or may do. 
§ 12. You shun the room in which you have seen a friend die. 
§ 13. A mother who has lost a very dear child sometimes 
loses with it all her joy, until time effaces the impression 
of this idea, which sometimes never 2 happens. § 14. A man 
perfectly cured of madness by an extremely painful operation 
acknowledged all his life his obligation to the one who per- 
formed this operation ; but it was impossible for him to 
endure the sight of the operator. § 15. Some hate books all 
their life because of the bad treatment they received in school. 
Some one having once gotten the upper hand of another upon 
some occasion keeps it always. § 16. A man was found 
who had learned to dance finely, but could not execute the 
dance unless there was in the room a trunk like the one 
which had been in the room where he had learned. § 17. 
The same non-natural bond is found in the intellectual habits ; 
you bind matter to being, as if there were nothing immaterial. 
§ 18. The sectarian party in philosophy, religion, and the 
state is attached to its opinions. 

Th. [This remark is important and wholly to my taste, and 
can be fortified by an infinite number of examples. Descartes 

1 Gerhard t reads: "sait"; Erdmann and Jacques: "suit," follow. — Tr. 

2 Gerhardt reads : " jamais " ; Erdmann and Jacques : " pas." — Tr. 



ch. xxxm] ON HUMAN UNDERSTANDING 283 

having had in his youth some affection for a squint-eyed per- 
son could not prevent himself from having all his life an incli- 
nation towards those who had this defect. Hobbes, another 
great philosopher, could not (they say) remain alone in a 
dark place, without having his mind frightened by images of 
ghosts, although he did not believe in them, this impression 
having remained from the stories told to children. Many 
persons well informed and sensible, and who are decidedly 
superior to superstition, cannot bring themselves to be thir- 
teen at a repast without being extremely disconcerted, having 
sometime been impressed by the' fancy that one of them must 
die during the year. There was a gentleman who, having 
been injured, perhaps in his infancy, by a badly fastened pin, 
could not see one in this condition without being ready to fall 
into a swoon. A prime minister, who bore in the court of his 
master the name of President, was offended by the title of the 
book of Ottavio Pisani, called Lymrgus, and wrote against this 
book, because the author, in speaking of the officers of justice 
whom he thought superfluous, had named also the Presidents, 
and although this term in the person of this minister meant a 
totally different thing, he had so attached the word to his 
person that he was wounded in this word. And this is a case 
of the most usual of the non-natural associations, capable of 
misleading, as those of words to things, when indeed there is 
any ambiguity. In order the better to understand the source 
of the non-natural bond of ideas, you must consider what I 
have already said above (Chap. 11, § ll 1 ), in speaking of the 
reasonings of animals, that man as well as the animal is 
inclined to put together in his memory and imagination what 
he has observed united in his perceptions and experience. It 
is in this that all the reasoning, if so it may be called, of 
animals consists, and often that of men, so far as they are 
empirical and govern themselves only by the senses and 
examples, without examining whether the same reason still 
has force. And as often the reasons are unknown to us, we must 
have regard to the examples in proportion to their frequency, 
for then the expectation or the reminiscence of one perception 

1 Cf. ante, p. 145. Gerhardt has § 1 ; Erdmanu and Jacques § 11 ; the latter 
reference is the correct one, and has therefore been placed in the text of the 
translation. — Tr. 



284 LEIBNITZ'S CRITIQUE OF LOCKE [bk. ii 

on the occasion 1 of another perception which is ordinary 
connected therewith is reasonable ; particularly when the 
question is about taking precautions. But as the vehemence 
of a very strong impression often produces as much effect 
at once as the frequency and repetition of many moderate 
impressions would be able to make in a long time, it happens 
that this vehemence engraves upon the fancy an image as 
profound and as vivid as long experience. 2 Whence it comes 
that a chance but violent impression unites in our imagination 
and memory two ideas, at that time together there, 3 altogether 
as strongly and durably and gives us the same inclination to 
connect them and to attend to them one after the other, as if a 
long usage had verified the connection ; thus the same result 
of association is found, although the same reason does not 
exist. Authority, party, 4 custom, produce also the same effect 
as experience and reason, and it is not easy to deliver one's 
self from these inclinations. But it would not be very 
difficult to keep one's self from being deceived in these judg- 
ments, if men would attach themselves seriously enough to 
the search for truth, or proceed methodically, when they 
recognize that it is important to them to find it.] 

1 Gerhardt reads: "d'une perception a l'occasion," which Erdmann and 
Jacques omit. — Tr. 

2 Erdmann and Jacques add : " auroit pu le faire," could have done. — Tr. 

3 Gerhardt reads : " qui y estoient ensemhle alors, tout aussi fortement et 
durahlement; et nous donne," etc. Erdmann and Jacques, " qui deja y 
e'taient ensemble, et nous donne," etc. — Tr. 

4 Erdmann and Jacques omit: "le parti." — Tr. 



NEW ESSAYS ON HUMAN UNDERSTANDING 



Book III. — Woeds 
CHAPTER I 

OF WORDS OB LANGUAGE IN" GENERAL 

§ 1. Ph. God having made man to be a social being, has not 
only inspired him with the desire, and placed him under the 
necessity of living with those of his species, but has given 
him also the faculty of speech which is to be the great instru- 
ment and common bond of this society. Hence it is that 
words arise, which serve to represent and also to explain 
ideas. 

Th. [I rejoice to see that you are averse to the view of 
Hobbes, 1 who did not admit that man was made for society, 

i Thomas Hobbes, 1588-1679, in bis De Cive, 1642, and Leviathan, 1651, 
maintained tbat man, being by nature a selfish and solitary animal, had no 
natural impulse for society, and that social union sprang simply from fear 
and from motives of gain, the natural condition being that of universal war. 
Leibnitz maintains, in agreement with Aristotle and Hugo Grotius, 1583-1645, 
that Nature herself has destined man for society in order not only that he 
may the better and more easily realize his highest being, but that he may 
realize it at all, such realization being impossible in isolation and solitude. 

Of. Aristotle, Polit. I., 2, 1253 a , 2: on ribv tpvasi ^ n-dAis lorri, koX oti <Jtv0pw7ros <pv<rei 
Tro\tTt.K.bv fuioc; HI. j 6, 1278 b , 19." (^uVci fjiev icmv aVflpcoTros £u>Of noXiriKOV, Sib Kal 
p.T)Sku Se6fJ.evoi ttj; nap' aWr/Kcov /3o->j0eia? ovk HXclttov bpeyovTai toS eru^jji', English trans- 
lation by B. Jowett, Vol. 1, pp. 4, 78, Oxford: Clarendon Press, 1885; also Eth. 

NlC. IX., 9, 1169 b , 3 Sq., espec. 16-19: aron-oi' 5' lo-ws Kal to ixovutt)V noteiv TOt> 
IJ.aKa.piov • oiiOei? yap cAoit' av Kad' avrbv to. ttolvt' ex* lv ayada ' no\iTiKbv yap 6 aV0pw7ros 

K al o-vfiv Tre^uKck, I., l, l094 h , 6 sq., English translation by F. H. Peters, pp. 307 
sq., 3 ; cf. also Zeller, Philos. d. GHeeh., II., 2 [Vol. 4], pp. 680, 662, 3d ed., 1879. 
Grotius, De Jure Belli et Pads, 1625, Preliminary Discourse, § 6: "Amongst 
the things peculiar to man, is his desire of society, that is, a certain inclination 
tcr live with those of his own kind, not in any manner whatever, but peace- 

285 



286 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

conceiving that lie has been forced into it by necessity and by 
the wickedness of those of his species. - But he did not con- 
sider that the best men, free from all wickedness, united them- 
selves the better to obtain their purposes, as the birds flock 
together the better to travel in company, and the beavers unite 
in large numbers to make great dams, in which work a small 
number of these animals could not succeed ; and these dams 
are necessary to them, to provide reservoirs of water or little 
lakes, in which they build their huts and catch the fish upon 
which they feed. This then is the foundation of the society 
of the animals which are adapted to it, and nowise,, the fear of 
their kind, which is rarely found among animals.] 

Ph. Very true, and it is the better to cultivate this society 
that man by nature has his organs so fashioned that they are 
adapted to the formation of the articulate sounds which we 
call words. 

Tli. [As for organs, monkeys have them apparently as suit- 
able as ours for the formation of words, but they do not take 
the least step in this direction. 1 Thus it must be that they 
lack an invisible something. We must also consider that we 

ably, and in a community regulated according to the best of his understand- 
ing, which disposition the Stoicks termed ouceiWis " ; quoted from Euglish 
translation with "all the large notes of Mr. J. Barbeyrac," etc., London: 
Printed for W. Innys and B. Manby, and others, 1738. A French translation 
by Jean Barbeyrac, professor of law at Groningen, "with the author's notes 
which had not yet appeared in French, and new notes by the translator," 

2 vols., 4to, Amsterdam, 1724; a later translation into English by Whewell, 

3 vols., 8vo, Cambridge, 1853 ; a German translation in J. H. v. Kirchmann's 
PJiilos. Bibliothek, 3 vols., 12mo, Leipzig, 1879. 

In the formation of society, language — Adyos, rational speech — plays an 
important part, serving as a special means of communication between men. 
Cf. Aristotle, Polit. I., 2-18, 1253* ; Grotius, De Jure Belli et Pads, Prelim. 
Disc. § 7: "A man grown up . . . has besides an exquisite desire of society, 
for the satisfaction of which he alone of all animals has received from nature 
a peculiar instrument, viz. the use of speech." — Tr. 

1 Schaarschmidt states that "this earlier generally diffused view, that the 
apes had organs of speech — an opinion still at the present day firmly held by 
the negroes — has already been refuted by Peter Camper," 1722-1789, a dis- 
tinguished Dutch anatomist and naturalist, in his Natuurkundige Verhand- 
elingen over den Orang-Outang an eenige andere Aapsoorten ; cf. p. 147 sq., 
of the German translation by J. F. M. Herbell. Diisseldorf, 1791, 4to. The 
most important of Camper's works bearing on comparative anatomy, trans- 
lated into French by H. C. Jansen, were published in (Euvres de P. Camper 
qui ont pour objet I histoire naturelle, la physiologie, et I'anatomie comparee. 
Paris, 1803, 3 vols., 8vo. The piece referred to in this note is found in Vol. 1 
of thised. — Tr. 



ch. i] ON HUMAN UNDERSTANDING 287 

could speak, i.e. make ourselves understood by the sounds of 
the mouth without forming articulate sounds, if we availed 
ourselves of musical tones for this effect ; but more art would 
be necessary to invent a language of tones, whilst that of 
words may have been formed and perfected gradually by per- 
sons who found themselves in a state of natural simplicity. 
There are, however, people like the Chinese, who by means of 
tones and accents vary their words, of which they have only a 
small number. Thus it was the opinion of Golius, 1 a cele- 
brated mathematician and great linguist, that their language is 
artificial, i.e. had been invented all at once by some clever man 
in order to establish verbal intercourse between the large num- 
ber of different nations inhabiting this great country which 
we call China, although this language may now be found 
altered by long use.] 

§ 2. Ph. [As orang-outangs and other monkeys have organs 
without forming words, we can say that parrots and some 
other birds have words without language], for we can train 
these birds and many others to form sounds quite distinct ; 
but they are nowise capable of language. Man only is in a 
condition to avail himself of these sounds as signs of internal 
conceptions, in order that thereby they may be manifested to 
others. 

Th. [I believe in fact that apart from the desire of making 
ourselves understood we should never have formed language ; 
but being formed, it further serves man in reasoning within 
himself, both by the means words give him of remembering 
his abstract thoughts, and the benefit he finds in availing him- 
self in reasoning of characters and surd thoughts ; for he 
would require too much time, if he were obliged to explain 
everything and always to substitute definitions in the place of 
terms.] 

§ 3. Ph. But as the multiplication of words would produce 

1 Jacob Gobi — Latin, Golius — 1596-1667, an eminent Dutch orientalist, 
who distinguished himself at Leyden University in classics, mathematics, and 
philosophy, was a pupil of Erpenius in Arabic, and in 1621 succeeded him as 
professor of Arabic at Leyden. In 1629 he returned from Asia Minor and the 
East, where he had spent four years, bringing with him a large and valuable 
collection of Mss. which he placed in the library of the university. His prin- 
cipal work, still to-day esteemed, is the Lexicon Arabico-Latinum, 1653, 
folio. — Tr. 



288 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

confusion in their use, if a distinct term were necessary to 
designate each particular thing, language has been further 
perfected by the use of general terms when they signify general 
ideas. 

Th. {General terms serve not only for the perfection of 
languages, but they are necessary even to their essential 
constitution. For if by particular things we mean individual 
things, it would be impossible to speak if there were only 
proper names and not appellatives, i.e. if there were words 
only for the individuals, since at every moment something 
now presents itself (to the mind) when individuals, accidents, 
and particularly acts, which are most frequently designated, 
are in question. But if by particular things we understand 
the lowest species (species infimm), besides the fact that it is 
difficult very often to determine them, it is manifest that they 
are already universals formed upon similitude. Then as the 
question is only of a similitude more or less extended, accord- 
ing as we speak of genera or species, it is natural to indicate 
every sort of similitude or agreement and consequently to 
employ general terms of all degrees ; and indeed the most 
general being less burdened with relation to the ideas or 
essences they include, although they are more comprehensive 
in relation to the individuals to which they apply, were very 
often the easiest to form and are the most useful. Thus you 
see that children and those who know only little of the lan- 
guage which they wish to speak, or of the matter of which 
they speak, avail themselves of general terms as thing, plant, 
animal, instead of employing the proper terms which they lack. 
And it is certain that all proper or individual names were 
originally appellative or general. 1 ] 

1 Leibnitz seems here to be in error in deciding from a logical or meta- 
physical point of view that language originated in or proceeded from general 
terms and relations rather than in those which are individual. In the order 
of experience the individual thing or relation is first, and first receives its 
name either wholly arbitrarily or by convention, or by this in combination 
with natural imitation or suggestion; the generalizing process and its result, 
the general name or term, comes afterwards. Children, it is true, use terms 
of general import, but with no consciousness that they are general. Every- 
thing is for them individual, particular, separate and by itself until continued 
observation and increasing knowledge enable them to detect similarities and 
differences and to classify and generalize accordingly. Then only do they, 
strictly speaking, possess or use general terms. — Tr. 



cn. i] ON HUMAN UNDERSTANDING 289 

§ 4. Ph. There are also words which men employ not to 
signify an idea, but the lack or absence of a certain idea, as 
nothing, ignorance, sterility. 

Tli. [I do not see why we could not say that there are 
privative ideas, as there are negative truths, for the act of 
denial is positive. I had already touched upon this.] 

§ 5. Ph. Without disputing about this point, it will be more 
useful to approach a little nearer the origin of all our notions 
and knowledge, to observe how the words employed to form 
actions and notions wholly removed from the senses, derive 
their origin from sensible ideas, whence they are transferred 
to significations more abstruse. 

Th. [The fact is our needs have compelled us to leave the 
natural order of ideas, for this order would be the same for 
angels, men, and all intelligences in general, and would have to 
be followed by us, if we had no regard for our interests. It 
has been necessary to attach thereto what the occasions and 
accidents to which our species is subject have furnished us ; 
and this order gives not the origin of the notions, but so to speak 
the history of our discoveries. 1 ^ 

Ph. [Very true, and it is the analysis of words which may 
teach us by means of the names themselves this concatenation 
which that of the notions cannot give by means of the reason, 
which you have brought forward.] Thus the following words : 
imagine, comprehend, to attach, conceive, instil, disgust, trouble, 
tranquillity, etc., are all derived from the operations of sensible 
things and applied to certain modes of thought. The word 
spirit in its primary signification is breath, 2 and angel signifies 
a messenger. Whence we can conjecture what kind of notions 

1 "The natural order of ideas," according to Leibnitz, proceeds from the 
general to the particular, from the abstract to the concrete, while language 
shows that "we have advanced from sense-impressions to abstract ideas," 
and thus " expresses not the essence of our knowledge, but only the history of 
its development. In a still broader sense the history of language is the history 
of the development of the human spirit in general." — Tr. 

2 Of. the Hebrew Pin (Spinoza, Tract. Theol. Polit., chap. 1, Opera, ed. Van 
Vloten and Land, Vol. 1, p. 384; English translation by Elwes, Vol. 1, p. 19) ; 
the Greek nvev^aL from weiv (Cremer, Bib. Theol. Lexicon of N. T. Greek, 2d 
English from 2d German ed., p. 504, Edinburgh : T. and T. Clark, 1878, says 
that as " the element of life " ..." in a physiological sense, we often find it 
(' nvevij.a ') in profane Greek, especially in the poets and in later Greek ; in a 
psychological sense, as the element of human existence and personal life, 
never") ; and the Latin spiritus from spirare. — Tii. 

U 



290 LEIBNITZ'S CRITIQUE OF LOCKE [ijk. hi 

they had who spoke these first languages and how nature will 
suggest unexpectedly to men the origin and the principle of all 
their knowledge by the terms themselves. 

Th. [I have already remarked to you that in the credo of 
the Hottentots they called the Holy Spirit by a term which 
signifies among them a breath of air benign and sweet. 1 The 
same is true as regards the majority of other words, and indeed 
the fact is not always recognized because most frequently the 
true etymologies are lost. A certain Dutchman, with little 
regard for religion, abused this truth (that the terms theology, 
ethics, and metaphysics are taken originally from gross things) 
in order to ridicule theology and the Christian faith in a little 
Flemish dictionary, in which he gave to the terms definitions 
or explications not such as usage demands, but such as the 
original force of the words seemed to bear, and put upon them 
a malicious interpretation ; and as he elsewhere had given 
indications of impiety he is said to have been punished in the 
Raspel-huys. 2 It will, however, be well to consider 'this analogy 
of sensible and non-sensible things which has served as the basis 
of tropes : a matter that you will understand the better by con- 
sidering a very extended example such as is furnished by the 
use of prepositions, like to, with, from, before, in, without, by, for, 
upon, towards (a, avec, de, devant, en, hors, par, pour, sur, vers), 
which are all derived from place, from distance, and from 
motion, and afterwards transferred to every sort of change, 
order, sequence, difference, agreement. To (a) signifies 
approach, as in the expression : I go to (a) Rome. But as in 
order to attach anything we bring it near that to which we 
wish to unite it, we say that one thing is attached to (&) 
another. And further, as there is, so to speak, an immaterial 
attachment, when one thing follows the other from moral 
reasons ; we say that what follows the movements and voli- 
tions of any one belongs to (a) that person or adheres to him 
as if it gave signs to this person to go near it or with it. A 

1 Cf. Book I., chap. 3, § 8, Th. The Apostle's Creed, the Ten Command- 
ments, and the Lord's Prayer in the Hottentot language, as sent to Leibnitz 
by N. Witsen, are given in Dutens, Leibnit. opera omnia, Vol. 6, Pt. 2, pp. 
204-206. Schaarschmidt remarks that "this observation of both philosophers, 
that the meaning of words has proceeded and still proceeds from the concrete 
to the abstract, is the guide to sound etymology and word-explanation." — Tb. 

2 Erdmann and Jacques have : " Raspel-huyss." — Is.. 



en. n] ON HUMAN UNDERSTANDING 291 

body is ivith (avec) another when they are in the same place ; 
but they say also that a thing is with (avec) that which is found 
in the same time, in the same order, or part of an order, or 
which concurs in one and the same act. When we come from 
(de) any place, the place has been our object through the 
sensible things it has furnished us, and it is still in our 
memory, which is entirely filled with it; and thence it comes, 
that the object is signified by the preposition of (de) as in the 
expression, the question is of (de) that, they speak of (de) 
that, i.e. as if it arose from it. And as what is included in 
any place or in any whole is supported by and carried away 
with it, the accidents are in the same way considered as in 
(dans) the subject, sunt in subjecto, inhcerent subjecto. The 
particle upon (sur) is also applied to the object; they say he 
is upon (sur) this matter, very much as a workman is upon 
(sur) the wood or upon (sur) the stone, that he cuts or forms; 
and as these analogies are extremely variable and do not de- 
pend on any determinate notions, it thence comes that 
languages vary much in the use of these particles and cases 
which the prepositions govern, or rather in which they are 
found as things understood and virtually included.] 



CHAPTEE II 

ON THE SIGNIFICATION OF WORDS 

§ 1. Ph. Now as words are employed by men as signs of 
their ideas, we may ask in the first place how their words have 
been determined ; and we find that it is not by any natural 
connection existing between certain articulate sounds and cer- 
tain ideas (for in this case there would be only one language 
among men), but by an arbitrary institution in virtue of which 
a given word has been purposely made a sign of a given idea. 1 

1 For early discussions of the nature and origin of language, and the ques- 
tion whether words were given by nature or convention, cf. Plato, Cratylus, 
English translation by B. Jowett, The Dialogues of Plato, 2d ed., 1875, Vol. 2, 
p. 203 sq. ; 3d ed., 1892, Vol. 1, p. 323 sq., New York : Macmillan & Co. ; Aristo- 
tle, De Interpret., 2, 16 a , 19 sq.; E. Wallace, Outlines of the Philos. of Aris- 
totle, 3d ed., § 11, p. 27. For modern discussions, cf. W. D. Whitney, Language 



292 LEIBNITZ'S CKITIQUE OF LOCKE [bk. hi 

Th. [I know it has been customary to say in the schools 
and almost everywhere else that the meanings of words are 
arbitrary {ex instituto) and it is true that they are not deter- 
mined by a natural necessity, but they are nevertheless 
determined by reasons sometimes natural, in which chance has 
some share, sometimes moral, where choice enters. There are 
perhaps some artificial languages which are wholly of choice 
and entirely arbitrary, as that of China is believed to have 
been, or as those of George Dalgarno l and the late Mr. Wil- 
kins, 1 bishop of Chester. But those which are known to have 
been coined from languages already known, are from choice 
mixed with what there is of nature and chance in the lan- 
guages they suppose. Thus it is in the case of those languages 
which thieves have coined in order to be understood only by 
those of their gang, which the Germans call Bothivelsch, 2 the 

and the Study of Language, Lect. XI., p. 395 sq., 4th ed., New York, 1869; 
B. Jowett, in his Introduction to Plato's Cratylus, op. cit., 2d ed., Vol. 2, p. 189 
sq.; 3d ed., Vol. 1, p. 281 sq. ; H. Steinthal, Einleitung in die Psychologie und 
Sprachwissenschaft ; Herm. Paul, Principien der Sprachgeschichte, Halle, 
1880; B. Delbriick, Einleitung in das Sprachstudium, Leipsic, 1880, 2d ed., 
1884. Leibnitz rightly points out that both nature and freedom of choice 
share in the formation of language. " Nature furnishes to a certain extent 
the material which the mind in its progressive self-absorption shapes within 
certain limits arbitrarily; and every human individual in the use of the 
language already formed is himself still so situated as to be able up to a 
certain point freely to appropriate and use that which is given." — Tr. 

1 George Dalgarno, c. 1626-1687, published at London in 1661, his Ars sig- 
norum, vulgo character universalis et lingua philosophica. Qua poterunt, 
homines diver sissimorum idiomatum, spatio duarum septimanarum, omnia 
animi sua sensa (in rebus familiaribus) non minus intelligibiliter, sive scri- 
bendo, sive loquendo, mutuo communicare, quam Unguis propiis vernaculis, 
from which Bishop John Wilkins, 1614-1672, derived the idea of his Essay 
toioards a real character and a philosophical language ivith an alphabetical 
dictionary. London, 1668. For Leibnitz's plan of a General Characteristic 
(Characteristic a Universalis — Specieuse ge'ne'raie) and the extent to which 
he followed Dalgarno and Wilkins, cf. Trendelenburg's paper : Ueber Leibni- 
zens Entiourf einer allgemeinen CharakteristiTc, in his Historische Beitrdge 
zur Philos., Vol. 3, p. 1 sq., Berlin, 1867 ; cf. also Gerhardt, Die philos. Schrift. 
v. G. W. Leibniz, Vol. 7, p. 3sq. ; Vol. 3, p. 216; Dutens, Leibnit. opera omnia, 
Vol. 6, p. 262. Dalgarno is credited with the invention of the first manual 
alphabet. His works were reprinted at Edinburgh, 1834, 4to. — Tr. 

2 Cf. Ave' Lallemant, Das deutsche Gaunerthum, 4 vols., Leipzig, 1858-1862, 
in which, says Schaarschmidt, " the so-called Rothwalsch, the artificial lan- 
guage of thieves in Germany, prominent already in the sixteenth and more so 
in the seventeenth century, is treated with especial thoroughness of detail. 
In this work it is shown that the Hebrew especially has contributed to the 
Gaunersprache a strong word-contingent, while its grammar is conformed to 



eh. ii] ON HUMAN UNDERSTANDING 293 

Italians Lingua Zerga, 1 the French Narquois, but which they 
usually form upon (the basis of) the languages commonly 
known to them, either by changing the received significations 
of the words by means of metaphors, or by making new words 
by means of a composition or derivation in their own fashion. 
Languages are also formed through the intercourse of different 
peoples, either by mingling indifferently neighboring lan- 
guages, or as most frequently happens, by taking the one as a 
base which is mutilated and altered, mixed and corrupted by 
neglecting and changing that which it observes, and even by 
grafting thereupon new words. The Lingua Franca, which is 
used in the commerce of the Mediterranean, is made from 
the Italian, and no regard is paid to the rules of grammar. 
An Armenian Dominican, with whom I conversed at Paris, 
had himself made, or perhaps learned from his fellows, a kind 
of Lingua Franca, made from Latin, which I found intelligible 
enough, although it had neither case, nor tense, nor other 
inflections, and he spoke it with ease, being accustomed to it. 
Father Labbe, 2 a French Jesuit, very learned, known by many 
other works, has made a language of which Latin is the base, 
which is easier and has less constraint than our Latin, but 
which is more regular than the Lingua Franca. He has made 
a book expressly of it. As for the languages which are found 
made a long time ago, there are but few which are not greatly 

the German. In Italy the Gaunersprache bears the name Gergo, which corre- 
sponds to the French Argot. To what extent in Leibnitz's time attention was 
directed to the Rothwalsch the romance literature shows ; but especially the 
Gesichte Philanders von Sittewald," a remarkable work, in which, under the 
name of Philander von Sittenwald, the author, Job. Mich. Moscherosch, 1600- 
1609, a German litterateur, whose true name was Kalbkopf , has given a series 
of satirical pictures of the caprices and the vices of society in his time, and 
which placed him among the best prose writers of his century. It was pub- 
lished at Strasburg, 1644-1650, 2 vols., 8vo. — Tr. 

1 Erdmann and Jacques read : " Gergo." — Tn. 

2 Philip Labbe, 1607-1667, a learned French chronologer, a man of vast 
memory, astonishing erudition, and great mental activity; a voluminous 
writer, and though gentle in personal character, a fierce and abusive contro- 
versialist. Leibnitz mentions him in a letter, July 15, 1709, to Geheimrath 
von Ilgen; cf. Gerhardt, Leibniz, philos. Schrift., 7, 36: "noch des P. Labbe 
(der die Lateinische mittelst einiger Veranderungen zur allgemeinen Sprach 
niachen wollen)." He was the author of Concordia chronologica, technica et 
historica, 1656 ; but is chiefly known to-day by his work on Latin pronuncia- 
tion, Erudites pronuntiationis catholici indices, enlarged by E. Leeds, and 
republished in London, 1751. — Tn. 



294 LEIBNITZ'S CRITIQUE OE LOCKE [bk. hi 

altered to-day. " This is evident by comparing them with their 
ancient books and monuments which remain. The .old French 
approached nearer the Provencal and the Italian, and we see 
the Theotisque 1 with the French or Komance rather (some- 
times called Lingua Romana rustica) as they were in the 
ninth century after Jesus Christ in the forms of the oaths of 
the sons of the Emperor Louis le Debonnaire, which Nithard, 
their kinsman, has preserved for us. 2 We find little elsewhere 
of so old French, Italian, or Spanish. But for the Theotisque, 
or ancient German, there is the gospel of Otfried, 3 a monk of 

1 Cf. Grimm, Deutsches Worterbuch, sub " Deutsch." — Tr. 

2 For the text of these famous oaths, taken at Strasburg, Feb. 14, 842, cf. 
Nithard, c. 790-c. 858, Hist., written, at the command of Charles the Bald, 
between 841 and 843, Bk. III., chap. 5, pp. 38, 39, ed. Pertz, and Pertz, Monu- 
menta Germanise Historica, Vol. 2, pp. 665, 666, where they are preserved in the 
old Romance — lingua Romana rustica — and old German — lingua Teotisca 
— languages. Cf. also Dutens, Leibnitii opera omnia, Vol. 6, Pt. II., pp. 141- 
144, where " utramque formulam (' jurarunt Ludovicus Romane, Carolus 
Teutonice ') eodem significatu, conceptis verbis ex Nithardo exhibebimus 
interlineariter colligatam, quia sibi verbotenus respondent, et ipso parallelismo 
illustrantur." The best edition for the study of the old German part of the 
oaths is in Karl Miillenhoff u. Wilhelm Scherer, Denkmdler deutscher Poesie 
u. Prosa aus VIII-XII Jahrh., Denkm. No. 67, 2 Ausg. Berlin, 1873; 3 Aufl. 
bearbeitet v. E. Steinmeyer. Vol. 2 contains notes summing up the best results 
of critical study. Explanations of the old German text have also been made 
by J. Grimm, 1785-1863, in his Kleinere Schriften, Vol. 6, pp. 403 sq., see 
also Monumenta Germanise Historica, Vol. 2, pp. 465 sq. ; and by H. F. 
Massmann, 1797-1874, in his Die kleinen Sprachdenkmale des VIII bis XII 
Jahrh. Quedliuburg u. Leipzig, 1839. Fr. Ch. Diez, 1794-1876, "the real 
founder of Scientific Romance philology and linguistics," in his Altromanische 
Sprachdenkmaler, Bonn, 1846, has explained the Romance portion of the text, 
and gives, op. cit. pp. 3-5, a good portion of the literature on this interesting 
linguistic monument. The best textual notes on the Romance or old French 
part of the oaths are in W. Foerster u. E. Koschwitz, Altfranzosisches llebungs- 
buch, Heilbronn, 1884 ; while the best facsimile of the whole fragment, both 
French and German, is the Album of the Societe des anciens textes francais 
(Les plus anciens monuments de la langue francaise), Paris, 1875. The old 
Romance text, the earliest specimen of French in existence, with a modern 
French translation, is found in Brachet, A Historical Grammar of the French 
Tongue, 6th English, from 20th French ed., pp. 17, 18, Oxford : Clarendon 
Press, 1884; while to these a Latin version is added for comparison in the 
article on the "Latin Language" prope fin., in the Encyclop. Brit., 9th ed., 
Vol. 14, pp. 340,341 (American Reprint). — Tr. 

3 The gospel of Otfrid, usually called the Life of Christ, was written in the 
South-Frankish dialect of the Old High German in 867 or 868, and dedicated 
to King Louis the German. Editions of it were published by Matthias Flacius 
Illyricus, 1520-1575, at Basle in 1571, Svo, "a book as curious as rare," and 
by Schilter-Scherz in the Thesaurus antiquitatum teutonicum., Vol. 1. Ulmae, 
1727-1728, 3 vols., f ol. These have now no critical worth, but merely an historical 



ch. n] ON HUMAN UNDERSTANDING 295 

Weissenburg of this same time, which Flacius has published 
and which Schilter * wished to edit anew. - The Saxons who 
passed into Great Britain have left us books still more ancient. 
They have a version or paraphrase of the beginning of Genesis 
and of some other parts of the Sacred History, made by a 
Cgedmon whom Bede already mentions. 2 But the most ancient 
book, not only of the Germanic languages, but of all the lan- 
guages of Europe, except Greek and Latin, is that of the 
gospel of the Goths of the Pontus Euxinus, known by the 
name of Codex Argenteus, 5 written in characters entirely pecu- 

interest and value. Cf. H. Paul, Grundriss d. germ. Philologie, II, 214, Stras- 
burg, 1889—. It has also been edited by E. Th. Graff, Konigsberg, 1831, 4to, an 
edition good in its day, but now antiquated ; and more recently by J. Kelle, 
with grammar and glossary in 3 vols., Regensburg, 1856-1881; by P. Piper, 
Paderborn, 1878, containing the fullest critical apparatus; and by Erdmann, 
Halle, 1882, the most convenient. Piper has also publisbed a student's edition, 
Freiburg, 1884; and Kelle a translation, Christi Leben vnd Lehre besungen 
von Otfrid, Prag. 1870. Cf. also W. Scherer, Gesch. d. deutschen Lit. 6th ed., 
pp. 48-51, Berlin, 1891; Eng. trans., from 3d Germ, ed., Vol. 1, pp. 44-46, 
New York, Chas. Scribner's Sons, 1886. To Otfrid is due, for the most part, 
the introduction into German poetry, in place of the earlier alliterative metre, 
of the rhymed stanza imitated from that of the Latin Church hymns. — Tr. 

1 John Schilter, 1632-1705, a distinguished German jurisconsult and archae- 
ologist, Professor of Law at Strasburg, and author of the work referred to in 
note 3, Thesaurus antiquitatum teutonicum, which was edited, after Schilter's 
death, by Job. Geor. Scherz, and is filled with documents of great value for 
the civil and literary history of Germany at the time of the Carlovingians. 
Schilter was led to linguistic studies through his legal and antiquarian investi- 
gations. Cf. Dutens, Leibnit. opera omnia, 6, Pt. II., p. 222, where Leibnitz 
remarks: "I am told that Mr. Schilter, of Strasburg, is none too well, and 
as he is an old man, I fear that his edition of Notger and Otfried will not 
appear. . . . Mr. Schilter makes use, moreover, of the Gothic Gospels of 
Ulfilas, of the Anglo-Saxon, and also of the Icelandic, as well as of other old 
books and glossaries ; for we must unite the different dialects of all the Teu- 
tonic peoples in order to explain the old books." — Tr. 

2 On Csedmon, died 680, cf. Bede, Eccles. Hist., Bk. IV., chap. 24, pp. 217- 
220, 5th ed. (Bonn's Lib.), London: Geo. Bell and Sons, 1884; H. Morley, Eng- 
lish Writers, Bk. II., chap. 4, Vol. 2, p. 71 sq., London: Cassell and Co., 1888; 
B. Ten Brink, Early Eng. Lit., trans, by H. M. Kennedy, pp. 39-48 and 371- 
386, New York : Henry Holt & Co., 1884 ; S. A. Brooke, Hist of Early Eng. Lit., 
pp. 275-340, New York: Macmillan & Co., 1892. For the text of the poems 
ascribed to him, cf. Benj. Thorpe, Csedmon's Metrical Paraphrase of Part of 
the Holy Scripture in Anglo-Saxon ; with an Eng. Trans., Notes, and a Verbal 
Index, London: 1832; C. W. M. Grein, Bibliothek der Angel-Sachsischen 
Poesie, 1857, Vol. 1 ; new ed. by R. Wiilker, Vols. 1-3, 1883-1889, still in prog- 
ress ; the vol. containing Caedtnon has not yet (1892) appeared ; T. W. Hunt, 
Csedmon's Exodus and Daniel, Boston : Ginn & Co., 4th ed., 1889. — Tr. 

8 The Codex Argeuteus — Silver Codex — so called because written in silver 
and gold letters upon purple-stained vellum and bound in silver, as was the 



296 LEIBNITZ'S CEITIQUE OF LOCKE [bk. hi 

liar, which was found in the ancient monastery of the Benedic- 
tines of Werden in Westphalia, and has been carried into 
Sweden, where it is preserved, as with reason it should be, 
with as much care as the original of the Pandects in Florence, 
although this version was made by the Eastern Goths and in a 
dialect far removed from the Scandinavian German ; but it is 
because they believe, with some probability, that the Goths 
of the Pontus Euxinus came originally from Scandinavia, or 
at least from the Baltic Sea. Now the language or the dialect 
of these ancient Goths is very different from the modern 
German, although it has the same linguistic basis. The 
ancient Gallic was still more different, to judge by the lan- 
guage most nearly approaching the true Gallic, which is that 
of the country of Wales, Cornwall, and Basse-Bretagne ; but 
the Irish differs therefrom still more and shows us traces of a 
Britannic, Gallic, and Germanic language, still more ancient. 
But all these languages come from one source, and may be 

case with costly Mss. in those days, originally consisted of 330 leaves con- 
taining the Gospels in the following order: Matt., John, Luke, Mark, trans- 
lated into the Gothic language, ahout the middle of the fourth century, by 
Bishop Ulfilas (Vulfila), 311-383. Only 177 leaves now remain. Cf. F. L. 
Stamm, Ulfilas, 1872, new ed. by M. Heyne, Paderborn, 1885, Einleitung, p. ix. 
The Ms., like all existing Gothic Mss., seems to have been written in Italy 
during the rule of the East Goths iu the first half of the sixth century, and, 
after many adventures, was at last carried in 1669 to Upsala, where it now 
is. It is one of the few sources of our knowledge of Gothic, and, as Ulfilas 
was a fine scholar, and made his translation of the New Testament from the 
Greek original, with frequent comparison of the LatiD versions, it is of some 
value in New Testament textual criticism. Editions of Ulfilas may be named 
as follows: The two earlier, by H. C. v. d. Gabelentz and J. Loebe, 3 vols., 
Altenburg u. Leipzig, 1843-1846, and H. F. Massmann, Stuttgart, 1855-1856, 
2 vols. 8vo, rest upon still older single editions with many faults. Cf. 
H. Paul, Grundriss d. germ. Philologie, II, 69, Anm. 2. The critical editions 
of A. Uppstrom : Codex Argenteus, Upsala, 1854-1855 ; Decern codicis arg. 
rediviva folia, ib. 1857; Fragmenta gothica selecta, ib. 1861; Codices gothici 
Ambrosiani, Stockh. u. Leipzig, 1864-1868, in whose work for the first time 
was laid an entirely secure foundation for Gothic text-criticism, and upon 
whom the later editions rest. Cf. H. Paul, op. cit. ; and Stamm-Heyne, 
Ulfilas, Einl. p. xi. The larger ed. of E. Bernhardt, Vulfila, oder die gotische 
Bibel, Halle, 1875, is the best for comparison with the Greek ; while his smaller 
ed., Die gotische Bibel des Vulfila, Halle, 1884, and that of Stamm-Heyne cited 
above are the most convenient. The best introduction to Gothic in English is 
J. Wright, A Primer of Gothic, London and New York, Macmillan & Co., 
1892. Cf. also W. Scherer, Gesch. d. deutschen Lit., 6th ed., pp. 33-36, Eng. 
trans., Vol. 1, pp. 28-32; Waitz, Das Leben des Ulfilas, 1840; Krafft, Kirchen- 
geschichte d. Deutschen Volker, Abth. 1, 1854, and article " Ulfilas," in Herzog, 
Realencyllopiidie, Vol. 16, 1885. — Tk. 



ch. n] ON HUMAN UNDERSTANDING 297 

taken as modifications of one and the same language, which 
may be called the Keltic. Thus the ancients called both the 
Germans and the G-auls Kelts; and in going back farther in 
order to understand the origin both of the Keltic and the 
Latin and the Greek, which have many roots in common with 
the Germanic or Keltic tongues, we may conjecture that this 
fact arises from the common origin of all these peoples de- 
scended from the Scythians, who, having come from the Black 
Sea, passed the Danube and the Vistula, and of whom one part 
may have gone into Greece, the other have filled Germany and 
the Gauls ; a consequence of the hypothesis which makes the 
Europeans come from Asia. The Sarmatian (supposing it to 
be the Sclavonic) has at least half its origin either Germanic 
or common with the Germanic. The case appears to be some- 
what similar, indeed, in the Finnish language, which is that of 
the most ancient Scandinavians, before the Germanic peoples, 
i.e. the Danes, Swedes, and Norwegians, had taken possession 
of the land which is the best and nearest the sea; and the 
language of the Finns or of the northeast of our continent, 
which is also that of the Lapps, extends from the German or 
Norwegian Ocean even to the Caspian Sea (although inter- 
rupted by the Sclavic peoples which have been thrust in 
between the two) and has some relation to the Hungarian, 
having come from the countries which are now in part under 
the Muscovites. But the Tartar language, which has filled the 
northeast of Asia, with its variations, appears to have been that 
of the Huns and Cumans as it is of the Uzbeks or Turkomans, 
of the Kalmuks and of the Mongols. Now all these languages of 
Scythia have many roots common among themselves and with 
ours, and it is found that even the Arabic (under which the 
Hebrew, the ancient Punic, the Chaldee, the Syriac, the Ethi- 
opia of the Abyssinians are to be comprised) has so great a 
number of them and an agreement so manifest with ours that 
it cannot be attributed to chance alone, nor even to commerce 
alone, but rather to the migrations of the peoples. So that 
there is nothing in this to combat and not rather to favor the 
view of the common origin of all nations, and of a primitive 
root language. 1 If the Hebrew or the Arabic approaches the 

1 Leibnitz was the first who, from the point of view of a presentiment of the 
kindred connection, first of the European, and then of the remaining Ian- 



298 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

nearest to it, it must be at least much changed, and the 
German seems to have preserved more completely the natural 
and (to use the language of Jacob Boehme) the Adamic; 1 for 
if we had the primitive language in its purity, or sufficiently 
preserved to be recognizable, the reasons of the connections 
whether natural or of an arbitrary institution would necessa- 
rily appear wise and worthy of the primitive author. But 
supposing that our languages are derivative as regards their 
foundation, they nevertheless have something primitive in 
themselves which has arisen from them in relation to new 
root words 2 since formed among them by chance but upon 
natural grounds. Those which signify the sounds of animals 
or have come from them furnish examples. Such, for exam- 
ple, is the Latin coaxare attributed to the frogs, which has 
some relation to couaquen or quaken in German. Now it 

guages, demanded and himself urged on the comparative study of languages, 
and in this, as in so many other things, was far in advance of his time. For 
his linguistic work, cf. Dutens, Leibnit. opera omnia, Vols. 5 and 6. — Tr. 

1 Jacoh Boehme, 1575-1624, a celebrated theosophist, in whom Protestant 
mysticism reached its highest point. He is called philosophus teutonicus, and 
"in reality through him, for the first time in Germany, did philosophy come 
forward with a characteristic stamp " ; Hegel, Vorlesimg. ii. d. Gesch. d. Philos., 
Vol. 3, p. 270, 2d ed., Berlin, 1833. O. Pfleiderer, Religionsphilosophie, Vol. 
1, p. 20, 2d ed., Berlin, 1883, says, "The theosophy of Boehme shows itself as 
the direct forerunner of the metaphysic of Leibnitz, 1646-1716, Schelling, 1775- 
1854, Baader, 1765-1841, Schopenhauer, 1788-1860, etc." For his philosophy, 
etc., cf. his Sammlliche Werke, hrsg. v. K. W. Schiebler, Leipzig, 1831-47, 2d 
ed., 1861 sq. ; also Hegel, op. cit., Vol. 3, pp. 270-297 ; Stockl, Gesch. d. Philos. 
d.Mittelalters,Vo].3,vp. 569-608, §§ 122-128; O. Pfleiderer, op. cit., Vol. 1, 
pp. 15-23, Eng. trans., Vol.1, pp. 13-23; B. Piinjer, Gesch. d. Christ. Religions- 
philos., 1880-83, Vol. 1, pp. 180-194; Eng. trans., Vol. 1, pp. 243-265, T. and 
T. Clark, Edinburgh, 1887. Vaughan, Hours with the Mystics, Vol.2, pp. 79-125, 
3d ed., London : 1879. According to Boehme, cf. Das dreyfache Leben, chap. 8, 
2-4; Princ, 10, 8-12; Myst. Mag., chap. 15, 1-9, etc. ; also Stockl, op. cit., §§ 
125, 126, Vol. 3, pp. 586 sg. ; Adam, who stands here in Leibnitz's text " as the 
symbol and representative of the original unity of the race," and of its lan- 
guage, " was destined to propagate his race in angel-like purity without 
endangering its integrity." Leibnitz, while acquainted with Boehme's writ- 
ings, made little use of them in his own thinking, and speaks thus of them in 
a letter to Fr. S. Loeffler, Jan. 13, 1693, cf. Dutens, op. cit., Vol. 5, p. 409 : " The 
controversies over the opinions of Boehme I consider idle, and think that he 
neither understood himself nor have others understood him." — Tr. 

2 Gerhardt's text reads: "Qui leur est survenu par rapport a des mots 
radicaux nouveaux, formes depuis chez elles," etc. Erdmann and Jacques 
read: "qui leur est survenu par rapport a des mots radicaux et nouveaux 
radicaux formes depuis chez elles," etc. ; i.e. new root words and new roots 
since formed among them, etc. — Tr. 



ch. n] ON HUMAN UNDERSTANDING 299 

seems that the noise of these animals is the primordial root of 
other words of the German language. For as these animals 
make much noise, the term is attributed to-day to idle talk and 
to babblers, who are called quakeler in the diminutive form ; 
but apparently this same word quaken was formerly under- 
stood in a good sense and signified all sorts of sounds made 
with the mouth not even excepting speech. And as these 
sounds or noises of animals are an evidence of life, and as we 
know thereby before we see it that there is life there, quek in 
old German has come to signify life or living, as may be 
observed in the most ancient books, and there are also traces 
of the same in the modern language, for QuecJcsilber is quick- 
silver (yif-argent) , and erquicJcen is to strengthen, and, as it 
were, to vivify or recreate after exhaustion or some great 
labor. Certain weeds are called also in Low German Quaken, 
alive so to speak and running, as they say in German, which 
spread and propagate themselves easily in the fields to the 
detriment of the grain; and in English quickly means promptly 
and in a wide-awake manner. Thus we may consider that as 
regards these words the German language may pass as the 
primitive, the ancients having no need to borrow elsewhere a 
sound which is the imitation of that of the frogs. And there 
are many others in which the same thing appears. For it 
seems that the ancient Germans, Kelts, and other peoples 
allied to them have employed by a natural instinct the letter R 
to signify a violent movement and a noise like that of this 
letter. 1 -It appears in piw, fluo, rinnen, riiren (fluere), rutir 
(fluxion), the Rhine, Rhone, Roer (Rhenus, Rhodanus, Erida- 
nus, Rum), rauben (rapere, ravir), Radt {rota), radere (raser), 
rauschen, a word difficult to translate into French ; it signifies 
a noise like that which the wind or a passing animal stirs up 
in the leaves or the trees, or is made by a trailing dress ; 
reckken (to stretch with violence), whence it comes that reichen 
is to reach ; that der Rick signifies a long stick or perch useful 
for suspending anything, in this kind of Plat-tiitsch or Low 
Saxon which is (spoken) near Brunswick; that Rige, Reihe, 

1 Of. Plato, Cratylus, 434 sq.; English Translation by B. Jowett; 2d ed., 
1875, Vol. 2, p. 259 sq.; 3d ed., 1892, Vol. 1, p. 381 sq., where the author has 
already made an attempt, similar to that made here and many times before 
by Leibnitz, to fix the original significance of single letters in the formation 
of words. — Tr. 



300 LEIBNITZ'S CEITIQUE OF LOCKE [bk. hi 

regula, regere, refer to length or a straight course ; and that 
Reck has signified a thing or person very extended and long, 
and in particular a giant, and then a powerful and rich man, 
as it appears in the reich of the Germans and in the riche or 
ricco of the Semi-Latins. In Spanish ricos hombres means the 
nobles or chief men ; and this makes it plain at the same time 
how metaphor, synecdoche, and metonymy have caused words 
to pass from one signification to another without our being 
able always to trace them. This noise and violent movement 
is noticed also in Riss (rupture) with which the Latin rumpo, 
the Greek pTJyw/ju, the French arracher, the Italian straccio are 
connected. Now as the letter R signifies naturally a violent 
movement, the letter L designates a gentler one. Thus we see 
that children and others who find the E. too harsh or too diffi- 
cult to pronounce substitute for it the letter L, saying, for 
example, mon levelend pele. 1 This gentle movement appears in 
leben (vivre — live), laben (conforter — comfort, faire vivre — 
make live), lind, lenis, lentus (lent — slow), Ueben (aimer — 
love), lauffen (glisser promptement comme Veau qui coule — to 
glide quickly like flowing water), labi (glisser — to touch 
lightly, labitur uncta vadis abies 2 ), legen (mettre doucement — to 
place gently), whence comes liegen (coucher — to lie down), 
lage or laye (un lit, comme un lit de pierres — a bed, as a bed of 
rocks), Lay-stein (pierre & couches, ardoise — slate), lego, icli lese 
(je remasse ce qu'on a mis — I collect what has been invested, 
it is the opposite of mettre — to place, and then je lis — I read, 
and finally among the Greeks je parle — I speak 3 ), Laub 
(feuille — leaf), a thing easy to stir, to which are related also 
lap, lid* lenken, luo, Auu> (solvo), leien 5 (in Low-Saxon) to dis- 
solve, to melt like the snow, whence the Leine has its name, 
a river of Hanover, which, rising in the mountainous coun- 
tries, is greatly enlarged by the melted snows ; not to speak 
of an infinite number of other similar appellations, which prove 
that there is something natural in the origin of words which 
indicates a relation between things and the sounds and move- 

i I.e. " Reverend pere." — Tr. 2 c/. Vergil, Mn. 8, 91. — Tb. 

3 Erdmann and Jacques omit: " Et puis je lis et enfin chez les Grecs je 
parle," the reading of Gerhardt. — Tr. 

4 Gerhardt's reading ; Erdmann and Jacques have " liel." — Tr. 

5 Gerhardt's reading; Erdmann and Jacques have "lien." — Tr. 



en. ii] ON HUMAN UNDERSTANDING 301 

rnents of the vocal organs ;- and it is furthermore for that 
reason that the letter L joined to other nouns makes their 
diminutives with the Latins, the Semi-Latins, and the High 
Germans. But it must not be pretended that this reason can 
be noticed everywhere, for the lion, the lynx, the wolf, are 
anything but gentle. But it may be attached to another acci- 
dent, the speed (lauf), which makes them feared or compels 
flight ; as if the one who sees such an animal coming should 
cry to the others : lauf (fuyez ! — fly !) ; besides by many acci- 
dents and changes the majority of words are very much 
altered and diverted from their pronunciation and original 
signification. 
Ph. Yet an example would make it better understood. 
Th. Here is one plain enough and which comprehends many 
others. The word ceil (eye) and its parentage may serve us. 
To show it I will begin a little further back. A (the first 
letter) followed by a little aspiration makes Ah, and as this 
is an emission of the air which produces a sound clear enough 
at its beginning and then vanishing, this sound naturally sig- 
nifies a light breath (sjtiritus lenis) when A and H are not 
very strong. Thence it is that aw, aer, aura, haugh, halare, 
haleine, aV/xo?, Athem, Oclem (in German) have had their origin. 
But as water is also a fluid and makes a noise, it has come 
(it seems) that ah made rougher by doubling, i.e. aha or ahha, 
has been taken as water. The Teutons and other Kelts, the 
better to indicate the motion, have placed their W before 
both. Thence wehen, Wind, vent, indicate the motion of the 
air, and ivaten, vadum, water, motion of or in the water. But 
to return to aha, it appears to be (as I have said) a kind of 
root which means water. The Icelanders, who preserve some- 
what of the Scandinavian Teutonic, have lessened the aspira- 
tion of some by saying aa; others, who say Aken (meaning 
Aix, Aquae grani 1 ), have increased it, as do also the Latins in 
their aqua, and the Germans in certain places, who say ach 
in compositions to indicate water, as when Schivarzach 2 means 
black water, Biberach water of the beavers. And instead of 
Wiser or Weser they said Wiseraha in the old titles, and 
Wisurach 2 among the ancient inhabitants, of which the Latins 

1 I.e. Aquis Granum, Aix-la-Chapelle. — Tr. 

2 Gerhardt's reading; Erdmann and Jacques read: " Schwartzach," 
" Wiserach." — Tr. 



302 LEIBNITZ'S CRITIQUE OE LOCKE [bk. m 

have made Visurgis, as from Iter, Ilerach, they have made 
Hargus. v From aqua, aigues, auue the French have finally 
made eau, which they pronounce oo, in which there no longer 
remains anything of its origin. Auwe, Auge with the Ger- 
mans is to-day a place which water often overflows, suitable 
for pasturage, locus irriguus, pascuus; but more particularly 
it signifies an island, as in the name of the monastery of 
Bekhenau {Augia dives), and many others. And this (process) 
must have gone on among many of the Teutonic and Keltic 
peoples, for thence it has come that everything which is, as 
it were, isolated in a kind of plain has been called Auge or 
Ouge, oculus. Thus it is they name spots of oil upon water 
among the Germans ; and among the Spaniards ojo is a hole. 
But Auge, Ooge, oculus, occhio, etc., have been applied more 
particularly to the ceil, as it were, pre-eminently, which makes 
this isolated brilliant foramen in the countenance ; and doubt- 
less the French ceil comes from it also, but its origin is not 
at all recognizable, unless by the concatenation I have just 
given ; and the ofifm and ctyis of the Greeks appear to come 
from the same source. Oe or Oeland is an island among the 
inhabitants of the North, and there is some trace of it in the 
Hebrew, where ^, Ai, is an island. Bochart 1 believed that 
the Phoenicians derived the name which he thinks they gave 
to the iEgean Sea, full of islands, from the same source. 
Auger e, augmentation, comes also from Auue or Auge, i.e. from 
the effusion of waters, as oohen, auken in old Saxon was to 
augment ; and Augustus, when speaking as Emperor, was trans- 
lated by Ooker. The river of Brunswick, which comes from 
the Hartz Mountains, and consequently is much subject to 
sudden accretions, is called Ocker, formerly Ouacra. And I 
mention in passing that the names of rivers, having ordinarily 

1 Samuel Bochart, 1599-1667, an eminent French scholar and Protestant 
theologian, a distinguished orientalist, and a man of profound erudition, 
thoroughly familiar with all the principal oriental languages, including 
Hebrew, Chaldaic, Syriac, and Arabic, and so enthusiastic in linguistic studies 
that even when far advanced in years he desired to learn Ethiopic. His 
favorite study was Phoenician, and though modest and candid he seeks to 
derive all languages etymologically " from the Hebrew or Phoenician," a pro- 
cedure which led him into many fanciful etymologies. Cf. Dutens, Leibnit. 
opera omnia, Vol. 6, Pt. II., pp. 223, 226. His complete works were published 
under the title, Sarn. Bochart, opera omnia. Leyden, 1675, 2 vols, fol., 1692, 
1712, 3 vols. fol. Leibnitz prized and often cited them. — Tk. 



ch. n] ON HUMAN UNDERSTANDING 303 

come from the farthest known antiquity, show best the old 
language and the ancient inhabitants ; hence they deserve 
particular investigation. And languages in general being the 
most ancient monuments of peoples, before writing and the 
arts, show best the origin of cognations and migrations. 
Hence etymologies much extended would be curious and sig- 
nificant; but it is necessary to unite the languages of many 
peoples, and not to make too many leaps from one nation to 
another far distant without having good verifications, in which 
process it is especially useful to have intervening peoples as 
guarantees. And in general credence must be given to ety- 
mologies only when there is a quantity of concurrent evidence ; 
to do differently is to goropise. 

Ph. To goropise? What does that mean? 

Th. It means that the strange and often ridiculous etymol- 
ogies of Goropius Becanus, 1 a learned physician of the sixteenth 
century, have passed into a proverb, although otherwise he 
may not have been excessively wrong in claiming that the 
German language, which he calls Cimbric, has as many, yes, 
more, marks of a primitive character than the Hebrew itself. 
I remember that the late Mr. Clauberg, 2 an excellent philoso- 

1 John Becan, 1518-1572, a Belgian physician and scholar, whose real name 
was Van Gorp — Latinized as Goropius Becanus.' He practised medicine for 
some years at Antwerp, hut finally gave himself wholly to the study of 
antiquity, belles-lettres, and ancient languages. In a public lecture at Liege, 
he attempted to demonstrate that the language of Adam was the Flemish or 
Teutonic, a view which he set forth at length in his Origines Antwerp ianse sive 
G'immeriorum Becceselana, etc., Antwerp, 1569, fol. ; and, as at that time he 
considered the Netherlands to be the site of Paradise, to derive language in 
general from the Low-German, which he calls the Cimbric, in his paper 
Hermathena, Bk. II., p. 25 sq. Cf. Joannis Goropii Becani opera hactenus in 
lucem non edita; nempe, Hermathena, etc., Antwerp, 1580, fol. — Tn. 

2 John Clauberg, 1622-1665, a German philosopher of the Cartesian school, 
who, first as a commentator merely and afterwards more independently, 
introduced and expounded the philosophy of Descartes in the universities at 
Herborn and Duisburg, where he was professor successively of theology and 
philosophy. He wrote a commentary on the Meditations of Descartes, and in 
his own speculations anticipated mucTi of the subsequent development of Car- 
tesianism. In his Be conjunctione animse et corporis liumani scriptiim, he 
maintained that bodily movements are antecedents only and not strictly causes 
of mental action, a view similar to that of Malebranche. He proposed for 
metaphysics the name Ontosophy or Ontology, a hint which Christian Wolf, 
1679-1754, afterwards followed. Cf. Erdmann, Grand, d. Gesch. d. Philos., 
§§ 268, 4, 290, 4, Vol. 2, pp. 33, 187, "3d ed., Berlin, 1878, and English trans, ad 
loc. His Ontosophia, de cognitione Bei et nostri appeared at Muhlberg, 1687, 



301 LEIBNITZ'S CRITIQUE OF LOCKE [BK.ra 

pher, has published a brief essay upon the sources of the 
German language which makes one regret the loss of that 
which he had promised upon this subject. i I have myself 
published some thoughts upon the subject, besides inducing 
the late Gerard Meier, 1 a theologian of Bremen, to work upon 
it, which he did till death interrupted him. I hope, however, 
that the public will yet one day profit from his labors as well 
as from the similar labors of Mr. Schilter, 2 a celebrated juris- 
consult at Strasburg, but who also has just died. It is certain 
at least that the Teutonic language and antiquities enter into 
the majority of the researches into European origins, customs, 
and antiquities. And I wish that learned men would make 
as much of them in the languages of the Wallachians, Bis- 
cayans, Slavonians, Finns, Turks, Persians, Armenians, Geor- 
gians, and others, the better to discover the harmony which 
would particularly be of service, as I have just said, in clearing 
up the origin of nations.] 

§ 2. Ph. [This design is important, but at present it is time 
to leave the matter of ivords, and to return to their form, i.e. to 

1 vol., 12mo; and his Opera philosophic a at Amsterdam, 1691, 2 vols., 4to. 
Leibnitz had a high regard for him, both as a philologist and philosopher, 
and in one expression apparently places him even above Descartes; " Carte- 
sius voluit qutedani emendare in physicis, displicet tamen audacia et fastns 
nimius conjunctus cum stili obscuritate, confusione, maledicentia. Longe magis 
mihi probatus Claubergius, discipulus ejus, plenus, perspicuus, brevis, method- 
icus." Cf. Otium Hanover 'anum, ed. J. F. Feller, p. 181, Lipsise, 1718; Dutens, 
Leibnit. opera omnia, Vol. 6, Pt. I., p. 311. Leibnitz frequently mentions him 
and his works, particularly the Meditationes et collectanea linguse Teutonicse, 
Duisburgi, 1663, and the booklet Ars etymologica Teutonum; cf. Dutens, 
op. cit., Vols. 5, p. 334; 6, Pt. II., pp. 28, 179, 22(X In the Ars etymol. Teuton. 
Clauberg puts it forth as a fundamental proposition that the German must be 
explained as an original language. Cf. L. Neff., G. W. Leibniz als Sprach- 
forscher mid Etymologe, Pt. I., p. 16 sq., Heidelberg, 1870. — Tr. 

1 Gerard or Gerhard Meier or Meyer, who was incited by Leibnitz to the 
study of German philology, and collected an abundance of select materials for 
a Grammatica Germanica and Glossarium Saxonicum, but was prevented 
from completing the work begun by his early and sudden death; cf. Eccard, 
Collectanea etymologica, 2 vols., 8vo, Haunoverse, 1717, Einleitung, p. 52, and 
Dutens, Leibnit. opera omnia, Vol. 6, Pt ll., p. 145, note. Leibnitz states that 
the Glossar. Saxon, was planned and undertaken with his encouragement, and 
that it will contain much erudition; cf. Dutens, op. cit., Vols. 5, p. 115; 6, 114, 
and note. For the correspondence between Meyer and Leibnitz, which exhib- 
its Meyer's method in his etymological work, cf. Dutens, op. cit., Vol. 6, Pt. 
II. , pp. 145-176. Leibnitz says : ' ' His learning and character are esteemed by 
all " — " Doctrina ejus, et virtus apud omnes in pretio habentur," Dutens, op. 
cit., Vol. 5, p. 105. — Tr. 2 Cf. ante, p. 295, note 1. — Tr. 



ch. 11] ON HUMAN UNDERSTANDING 305 

the meaning which is common to the different languages.] 
Now you will agree with me in the first place, sir, that when 
one man speaks to another it is of his own ideas that he wishes 
to give signs ; the words cannot be applied by him to things 
which he does not know. And until a man has ideas of his 
own he cannot suppose them to correspond to the qualities of 
things or to the conceptions of another. 

Th. [It is true, however, that he intends very often to 
indicate what others think rather than what he himself 
thinks, as happens only too much in the case of the laity, 
whose faith is implicit. But I admit that he always means 
something general, however hollow and destitute of intelli- 
gence the thought may be ; and he takes pains at least to 
arrange his words according to the custom of others, content- 
ing himself with the belief that their sense can be apprehended 
at need. Thus he is sometimes only the interpreter (truche- 
man) of thoughts, or the bearer of the word of another, just as 
a letter would be ; and indeed this is the case oftener than you 
think.] 

§ 3. Ph. [You are right in adding that he always means 
something general, however idiotic it may be.] A child hav- 
ing noticed in what he hears called gold only a brilliant yellow 
color, gives the name of gold to this same color which he sees 
in a peacock's tail; others will add great weight, fusibility, 
malleability. 

Th. [I admit it; but often the idea you have of the object 
of which you speak, is still more general than that of this 
child, and I doubt not that a blind person can speak pertinently 
of colors and make a speech in praise of the light which he 
does not know, because he has learned its effects and circum- 
stances.] 

§ 4. Ph. Your remark is quite true. Men often apply their 
thoughts more to words than to things, and because they have 
learned most of these words before becoming acquainted with 
the ideas which they signify, not only children, but also grown- 
up men often speak like parrots. § 5. But men ordinarily mean 
to indicate their own thoughts, and further they attribute to 
words a secret relation to the ideas of another and to things 
themselves. For if the sounds were attached to another idea 
by the one with whom we are conversing, it would be necessary 
x 



306 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

to speak two languages. It is true that one does not stop too 
much to examine what the ideas of others are, and our idea is 
supposed to be that which the common people and the scholars 
of the country attach to the same word. § 6. This is particu- 
larly the case as regards simple ideas and modes ; but as 
regards substances the belief is more particularly that the 
words signify also the reality of things. 

Th. [Substances and modes are equally represented by 
ideas; aud things, as well as ideas, in both cases are indi- 
cated by words ; thus I see but little difference, save that 
ideas of substances and of sensible qualities are more fixed. 
For the rest, it sometimes happens that our ideas and thoughts 
are the matter of our discourse and constitute the thing itself 
which we desire to signify, and that reflective notions enter 
more than we think into those of things. We speak, indeed, 
sometimes of words in a material way, without in this case 
being able to substitute with precision in the place of the 
word its signification or its relation to the ideas or things. 1 

1 Leibnitz here points out a source of manifold, far-reaching and influential 
errors, especially fatal in philosophy, viz. the hypostasizing of concepts, i.e. 
regarding and using universal thought-symbols as substances, a consequence 
of the excessive use of abstract terms. To these errors thus arising from the 
imperfection and abuse of words and their influence on the mind, Francis 
Bacon, 1561-1626, in his Nov. Org. Bk. I., Aphor. 43, 59, 60, gives the name 
of idolafori, idols of the market-place, and says they are "omnium molestis- 
sima " — " the most troublesome of all." These words are either names merely 
of non-existent things or of things supposed to exist because of these names, 
or are names obtained by "vicious and unskilful abstraction" — "mala et 
imperita abstractione " — from a few objects and indiscriminately applied to 
all other things having the faintest analogy thereto. The best ed. of Bacon's 
Works is that of Ellis, Spedding, and Heath, 2d ed., 7 vols., London: Long- 
mans, 1870-72. The Nov. Org., in Latin, is in Vol. 1, the Eng. trans, in Vol. 4 
of this ed. Editions of the Nov. Org. (Latin) have been published with Eng. 
notes, and an Eng. trans, in a separate vol., by G. W. Kitchin, Oxford: Clar- 
endon Press, 1855; aud with Iutrod., Notes, etc., by Thos. Fowler, Oxford: 
Clarendon Press, 1878. 

For Leibnitz's estimate of Bacon, whose Be Aug. Scient. he mentions 
among the writings which happily chanced to come into his hands when a 
youth, and with others helped to direct his studies in the right path, whom he 
enumerates among " the founders of modern philosophy," and whose method 
he applied in his reform of the science of language, cf. Gerhardt, Die philos. 
Schrift. v. G. W. Leibniz, Vols. 1 : 196; 3 : 7, 16; 4 : 143, Erdmann, Leibnit. 
opera philos., p. 61, b ; G. 4 : 64, E. 23, a ; G. 4 : 105, E. 45, a, also G. 7 : 325, 
E. 110, b; G. 4 : 337, 343; 7 : 52, 53, E. 91, b, 92; G. 7 : 67; 7 : 495, Dutens. 
Leibnit. opera omnia, 5 : 368; 6 : 303; G. 7 : 518, E. 421, a. Cf. also John 
Nichol, Bacon, Vol. 2, pp. 238-239 (Philos. Classics) , Edinburgh : Win. Black- 



en. in] ON HUMAN UNDERSTANDING 307 

This occurs not only in speaking as a grammarian, but also in 
speaking as a lexicographer, in giving the explication of the 
term.] 



CHAPTER III 

OF GENERAL TEEMS 

§ 1. Ph. Although particular things alone exist, the larg- 
est number of words are general terms, because it- is impossible, 
§ 2, for each particular thing to have a particular and distinct 
name ; besides the fact that in such case a prodigious memory 
would be necessary, in comparison with which that of certain 
generals who could call by name all their soldiers would be 
nothing. The matter indeed becomes infinite, if every animal, 
every plant, and even every leaf of a plant, every grain, in 
short every grain of sand, which might need a name must 
have its name. [And how name the parts of things sensibly 
uniform, as water, fire ?] § 3. Besides, these particular names 
would be useless, the principal end of language being to 
excite in the mind of him who listens to me an idea similar to 
mine. [Thus the similitude suffices, which is indicated by 
general terms.] § 4. And particular words alone would not 
serve to extend our knowledge, [nor to make us judge of 
the future by the past, or of one individual by another.] 
§ 5. But as it is often necessary to mention certain individuals, 
particularly of our species, use is made of proper names ; which 
are given also to countries, towns, mountains and other dis- 
tinctions of place. And horse-jockeys give proper names 
even to their horses, as well as Alexander to his Bucephalus, 
in order to be able to distinguish this or that particular horse 
when he is out of their sight. 

Th. [These remarks are good, and some of them agree 
with those I was about to make. But I would add, in accord- 
ance with the observation I have already made, that proper 
names have been ordinarily appellatives, that is to say, general 

wood & Sons, 1889. For a brief comparison of Leibnitz and Bacon and of 
their philosophies, cf. J. T. Merz, Leibniz, pp. 21, 71 (Blackwood's Philos. 
Classics) , Edinburgh : 1884. — Tr. 



308 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

in their origin, as Brutus, Caesar, Augustus, Capito, Lentulus, 
Piso, Cicero, Elbe, Ehine, Buhr, Leine, Ocker, Bucephalus, 
Alps, Brenner or Pyrenees ; for you know that the first 
Brutus had this name from his apparent stupidity, that 
Caesar was the name of a child drawn by incision from the 
womb of his mother, that Augustus was a name of veneration, 
that Capito is a large head as also Bucephalus, that Lentulus, 
Piso, and Cicero were names given in the beginning to those 
who cultivated in particular certain kinds of vegetables. I 
have already said what the names of these rivers signify, 
Ehine, Euhr, Leine, Ocker. And you know that all rivers are 
still called Elbe in Scandinavia. Finally Alps are mountains, 
covered with snow (with which agrees album, white) and 
Brenner or Pyrenees signifies a lofty pride, for bren was high 
or chief (as Brennus) in Keltic, as also brincJc with Low- 
Saxons is pride, and there is a Brenner between Germany and 
Italy as the Pyrenees are between Gaul and Spain. Thus I 
would venture to say that nearly all words are originally gen- 
eral terms, because it will only rarely happen that an express 
name will be invented without reason to indicate one such 
individual. We can say then that the names of individuals 
were names of a species which was given par excellence or 
otherwise to some individual, as the name large head to that 
one of the whole city who had the largest or who was the 
most important of the large heads which were known. Thus 
it is indeed that we give names of genera to the species, i.e. 
that we shall content ourselves with a term more general or 
more vague to designate more particular species, when we 
have no concern for their differences. For example, we are 
contented with the general name, wormwood, although there 
are so many species of it that one of the Bauhins * has filled a 
book expressly with them.] 

1 Jean Bauhin, 1541-1613, a Swiss physician and naturalist, who devoted 
himself chiefly to botany, and with his brother Gaspard, 1560-1624, also a 
physician and botanist, was born at Basel, whither his father, an eminent 
French physician, had fled in exile because of his conversion to Protestant- 
ism. He studied with the celebrated botanist Fuchs at Tiibingen, and after 
travelling and collecting plants in the Alps, in France, and in Italy, became, 
in 1570, physician to Duke Uirich of Wiirteniberg at Montbeliard, where he 
remained till his death. The work of bis to which Leibnitz here alludes is 
entitled De plantis absinthii nomen habentibus. It appeared at Montbeliard 



en. in] ON HUMAN UNDEKSTANDING 309 

§ G. Ph. Your reflections upon the origin of proper names 
are very just ; but to come to that of appellative names or 
general terms, you will doubtless agree, sir, that words 
become general when they are signs of general ideas, and 
ideas become general when separated by abstraction from 
time, place, or such other circumstances as may determine them 
to this or that particular existence. 

Th. [I do not deny this use of abstraction, but it is rather 
in ascending from species to genera than from individuals 
to species. For (paradoxical as it may appear) it is impos- 
sible for us to have the knowledge of individuals, and to 
obtain the means of determining exactly the individuality of 
anything, at least of keeping it by itself ; for all the circum- 
stances may reappear ; the smallest differences are to us insen- 
sible ; place or time, far from determining themselves, need 
themselves to be determined by the things they contain. The 
most important factor in the problem is the fact that individu- 
ality includes infinity, and only he who is capable of com- 
prehending it can have the knowledge of the principle of 
individuation of this or that thing. This arises from the 
influence (understanding it healthfully) of all things in the 
universe upon each other. It is true that this would be 
the case, if the atoms of Democritus existed, but in that case 
also there would be no difference between two different individ- 
uals of the same form and size.] 

§ 7. Ph. It is, however, wholly evident that the ideas which 
children frame of persons with whom they converse (to con- 
fine ourselves to this example) are similar to the persons 
themselves, and particular only. The ideas they have of 
their nurse and their mother are very well traced in their 
minds, and the names nurse and mamma, which children use, 
relate only to these persons. Afterwards when time has 
shown them that there are many other beings resembling 

in 1593. His most important work, composed with the assistance of his fellow- 
countryman and son-in-law Cherler, and containing descriptions of about 5000 
plants with 3577 figures, is the Historia universalis plantarum nova et absolu- 
tissima, Yverdun, 1650-1651, 3 vols., fol. An abridgment of this great work 
was published by Chabree, of Geneva, with the title Sciagraphia, 1666, con- 
taining in one volume all the figures, together with all of importance on the 
nomenclature and number of species in the great work. He was one of the 
founders of modern botany. — Tr. 



310 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

their father or mother, they form an idea in which they find 
that all these particular beings equally share, and they, as 
others, give it the name of man. § 8. They acquire in the 
same way names and notions more general ; for example, the 
new idea of animal is not produced by any addition, but only 
by removing the figure or the particular properties of man, 
and retaining a body accompanied by life, feeling, and spon- 
taneous movement. 

Th. [Very well ; but that shows only what I just said ; for 
as the child advances by abstraction from the observation of 
the idea of man to that of the idea of animal, he has come 
from the more specific idea observed in his mother or father 
and in other persons to that of human nature. For in order 
to discern that he had not the precise idea of the individual, 
it is sufficient to consider that an ordinary resemblance would 
deceive him easily and make him take as his mother another 
woman. You know the story of the false Martin Guerre, 1 who 
deceived even the wife of the true, and the near relatives, by 
resemblance united with skill, and embarrassed for a long 
time the judges, even when the true Martin had arrived.] 

§ 9. Ph. Thus this whole mystery of genus and species, 
which makes so much noise in the schools, but which outside 
of them is with reason so little regarded, this whole mystery, 
I say, reduces itself solely to the formation of abstract ideas 
more or less extended, to which certain names are given. 2 

1 Gf. Essais de Thdodice'e, Discours preliminaire, § 42, Gerhardt, 6, 74, 
Erdmann, 491, b, Jacques, 2, 48. In the sixteenth century, Martin Guerre, a 
gentleman of Gascony, disappeared from home. After a long absence, a man 
by the name of Arnaud du Thil suddenly appeared, claiming to be Martin 
Guerre, and was acknowledged by the wife of Guerre as her husband. She 
had by him two children. Learning, afterwards, that her true husband was 
in Flanders, she angrily delivered the impostor into the hands of justice. The 
long trial, one of the most celebrated cases of the century, was brought to an 
end by the sudden and unexpected arrival of the true Martin Guerre, and 
Du Thil was sentenced to death. For further details, and the sentence in full, 
cf. P. Larousse, Grand Diet. Universel de XIX e Steele, Vol. 8, p. 1603, b, c. 
A parallel case in recent times was the Tichborne trial in England. — Tk. 

2 The philosophies of Locke and Leibnitz present a sharp contrast on the 
question of genera and species, and the real existence of the universal. Accord- 
ing to Locke, the question is a wholly empty one, an inheritance from the 
unprofitable discussions of scholasticism. The general term, the universal, is 
a purely subjective product of the more or less arbitrary activity of man in 
abstraction, and has nothing whatever to do with reality. Leibnitz maintains 
that the universal is the inner essence of things, and that the formation of 



en. in] ON HUMAN UNDEKSTANDING 311 

- Th. [The art of classifying tilings into genera and species 
is of no little importance and of much use both to the judg- 
ment and the memory. You know how important this is in 
botany, not to speak of animals and other substances, and 
without mentioning also beings moral and notional, 1 as some 
call them. Order largely depends upon it, and many good 
authors so write that their entire discourse can be reduced to 
divisions and subdivisions, according to a method which has 
some relation to genera and species, and is of use not only in 
retaining things, but also in finding them. 2 And they who 
have arranged all sorts of notions under certain titles or pre- 
dicaments subdivided have done a very useful thing.] 

§ 10. Ph. In defining words, we avail ourselves of the genus 

general terms is not a mere thought-expedient, but a legitimate and proper 
apprehension of the true and the real. Cf. G. Hartenstein, Locke's Lehre v. d. 
menschl. Erkenntniss in Vergleichung m. Leibniz's Kritik derselben, V., 
pp. 52 sq. , also in his Histor. Philos. Abhandl., Leipzig, 1870, pp. 162 sq. — Tr. 

1 Notional or conceptional beings, begri.fliche Wesen, entia rationis, are 
those which, as Sehaarschmidt says, " serve to indicate that which without 
being in the ordinary sense of the word substantial (first substance in the 
language of Aristotle," cf. Ccdegor. 5, 2 a , 11 ; Wallace, Outlines of the Philos. 
of Aristotle, § 10, p. 25 ; Zeller, Philos. d. Griech., II., 2 [Vol. 4], p. 304 sq., 3d ed., 
1879; but cf. also, Metaphys. VII., 7, 1032k, 2; Wallace, op. cit. § 34, p. 67, 
Zeller, op. cit. II. 2 [Vol. 4], p. 344 sq.) " can still lay claim to an ideal reality." 
For further discussion of the subjects of this and the note next preceding, 
cf. Neiu Essays, Bk. III., chaps. 5, 6, Bk. IV., chaps. 4, 6. — Tr. 

2 Cf. Gerhardt, Leibniz, philos. Schrift. 7, 67: " Fuere tameu autores non 
contemnendi, qui methodum rebus junxere ut Theodoras Zwingerus, Joh. 
Thomas Freigius, Barthol. Kechermannus, et diligentissimus Joh. Henr. 
Alstedius, cujus Encyclopaedia mini pro captu illorum temporum laudanda 
videtur." Alsted, 1588-1638, was Professor of Philosophy and Theology at 
Herborn in Nassau, but applied himself chiefly to systemizing the several 
branches of art and science. His Encyclopaedia, Herbornise, 1630, 7 vols., fol., 
reprinted Lugduni, 1649, 4 vols., fol. Leibnitz often mentions it (cf. G. 4, 62, 
74, E. 22, a, 28, b; Dutens, Leibnit. opera omnia, 5, 405, 567), and wrote down 
some thoughts — cogitata qusedam — for its enlargement and improvement; 
cf. Dutens, 5, 183-185. The classified contents of the work are given in the 
article "Encyclopaedia," in the Encyclop. Brit. 9th ed., Vol. 8, p. 176, b 
(American Reprint). Sehaarschmidt states that the different works of R. 
Goclen, as well as those of Alsted, are of the kind alluded to in the text. 
Goclen, 1547-1626, was Professor of Philosophy at Marburg, and published a 
Lexicon philosophicum, Marburg, 1613, 1 vol., 4to, which, though of little 
value, enjoyed from its novelty considerable celebrity at the time of its appear- 
ance. Leibnitz refers to this work in his third letter to Clarke; cf. G. 7, 365, 
E. 752, b, J. 2, 426, D. 2, 122. Goclen was the ' discoverer and signalizer ' of 
the Inverse, Regressive, or Goclenian Sorites, in comprehension ; cf. Hamilton, 
Lects. on Logic, XIX., p. 273, Amer. ed., and Goclenii Isagoge in Organum 
Aristotelis, p. 255, Francof. 1598. — Tr. 



312 LEIBNITZ'S CRITIQUE OE LOCKE [bk. hi 

or the next general term ; and this is for the purpose of spar- 
ing ourselves the trouble of counting the different simple ideas 
which this genus signifies, or sometimes perhaps for the pur- 
pose of sparing ourselves the disgrace of being unable to make 
this enumeration. But although the shortest way of defining 
is by means of genus and difference, as the logicians say, it may 
be doubted, in my opinion, whether it is the best ; at least it 
is not the only way. In the definition which states that man 
is a rational animal (a definition which is perhaps not the 
most exact, but which serves well enough the present pur- 
pose), instead of the word animal you might put its definition. 
And this shows the little necessity of the rule which requires 
that a definition must be composed of genus and difference, 1 and 
the little advantage there is in its strict observance. Thus 
languages are not always made according to the rules of logic, 
so that the meaning of each term may be exactly and clearly 
expressed by two others. And those who made this rule have 
done ill in giving us so few definitions conformable to it. 

Th. [I agree with your remarks ; it would be advantageous, 
however, for many reasons, if definitions might consist of two 
terms : it would without doubt greatly shorten them, and all 
divisions could be reduced to dichotomies which are the best 
species of divisions, and are particularly useful for invention, 
judgment, and memory. I do not, however, think logicians 
always demand that the genus or the difference be expressed 
in a single word ; for example, the term regular polygon may 
pass as the genus of the square, and in the figure of the circle 
the genus might be a plane curvilinear figure, and the dif- 
ference might consist in the fact that all points of the circum- 
ference are equally distant from a certain point as centre. 2 

1 Cf. Aristotle, Topica, VI., 4, 141 b , 26 : Set fxev Sia tou yeVous Ktii t£>v Sia<popui> 
bpi^ecrQai tov k<xAw; opi^d/ievov, also I., 8, 103^, 15 : e'reicSi) 6 6pi<rp.b<; e« yeVovs Ka\ Siaifiopwv 

eo-nV, and Wallace, Outlines, §§ 14, 15, 25; Zeller, Philos. d. Griech., II., 2 
[Vol.4], p. 255.— Tr. 

2 Leibnitz rightly takes exception to Locke's censure of Aristotle's rule 
regarding definition, given in the preceding note, viz. : that it must consist of 
the genus and the species-forming difference, remarking that genus and dif- 
ference may very often he interchanged, the possibility of this interchange 
depending upon the principle on which, or the point of view from which, the 
classification is made, or upon the closeness with which the genus and the 
species-forming difference approach each other, it being essential to valid 
interchange that they be actually alike, or so nearly so that the difference is 



ch. in] ON HUMAN UNDERSTANDING 313 

For the rest, it is also well to remark that very often the genus 
may be changed into a difference and the difference into a 
genus. For example, the square is a regular quadrilateral, or 
rather a four-sided figure that is regular, so that the genus 
or the difference seems to differ only as the substantive and 
adjective ; as if, instead of saying that man is a rational living 
being (animal raisonnable) , language allowed the statement 
that man is a living rational being (rational animable), i.e. 
a rational substance endowed with an animal nature ; while 
genii : are rational substances whose nature is not animal or 
common with the animals. And this interchange of genera 
and differentia depends upon the variation of the order of the 
sub-divisions.] 

§ 11. Ph. It follows from what I have just said, that what 
is called general and universal belongs not to the being (exist- 
ence) 2 of things, but that it is a work of the understanding, 
§ 12, and the essences of each species are only abstract ideas. 

Th. [I do not quite see this consequence. For generality 
consists in the resemblance of separate things among them- 
selves, and this resemblance is a reality.] 

§ 13. Ph. I was going myself to say to you that these species 
are founded upon resemblances. 

Th. [Why, then, not seek therein also the essence of genera 
and species ?] 

§ 14. Ph. You will be less surprised to hear me say that 
these essences are the work of the understanding, if you con- 
sider that there are at least complex ideas which in the minds 
of different persons are often different collections of simple 
ideas, and thus what is avarice in the mind of one man is not 
so in the mind of another. 

practically of no account. Cf. Neiv Essays, Bk. III., chap. 3, ante, p. 308. 
Such definitions, while not strictly logical or scientific in the full sense of these 
terms, hut tentative rather, and, as it were, popular, are nevertheless useful, 
and indeed necessary, in ordinary life and in science, where we must classify 
to a certain extent for the sake of relative clearness, hut where strict logical 
definition is not essential, or is impossihle because of the insufficiency of our 
knowledge. Logically exhaustive definition, save in the realm of pure thought 
and in such sciences as the pure mathematics, is possible only to an infinite 
mind who possesses exhaustive knowledge of all principles and facts involved. 
Exhaustive knowledge of an individual demands an exhaustive knowledge of 
all other individuals. Cf. N. E., Bk. III., chap. 3, § 6, Th., ante, p. 309. — Tb. 

1 I.e. angels and archangels. — Tr. 

2 Locke has : " real existence," Philos. Wks., Vol. 2, p. 14 (Bonn's Ed.).— Tk. 



314 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

Th. [I admit, sir, that there are few cases in which I have 
less understood the force of your inferences than here, and 
this troubles rne. If men differ in the name, does it change 
the things or their resemblances ? If one applies the name 
avarice to one resemblance, and another to another, there will 
be two different species designated by the same name.] 

Ph. In that species of substance which is most familiar to 
us and with which we are most intimately acquainted, it has 
many times been doubted whether the offspring brought into 
the world by a woman was a man, 1 even to discussing whether 
he should be fed and baptized. This could not be if the ab- 
stract idea or the essence, to which the name man belongs, 
were the work of nature, and not a diverse, uncertain collection 
of simple ideas which the understanding put together, and to 
which it attached a name, after having made it general by 
way of abstraction. So that at bottom each distinct idea, 
formed by abstraction, is a distinct essence. 

Th. [Pardon me for telling you, sir, that your language 
perplexes me, for I do not see its connection. If we cannot 
always discern by the outside the internal resemblances, are 
there less of them in nature ? When we doubt whether a 
monster is a man, we doubt whether it has reason. When we 
know it has, the theologians will order it to be baptized, and 
the jurisconsults, to be fed. It is true that we may dispute 
about the lowest species logically considered, which vary by 
accidents in one and the same physical species, or species by 
direct descent (tribu de generation*)? but we do not need to 
determine these ; we may, indeed, vary them infinitely, as is 
seen in the great variety of oranges, lemons, and citrons, which 
experts know how to name and distinguish. The same thing 
was seen in tulips and pinks when these flowers were in 
fashion. For the rest, the fact that men unite these or those 
ideas, or even that nature actually unites them or not, makes 
no difference as regards essences, genera, or species, since the 
question only concerns possibilities, which are independent of 
our thought.] 

1 Of. Locke, Philos. Works, Vol. 2, p. 17, and note (Bonn's Ed.). — Tr. 

2 Cf. New Essays, Bk. III., chap. 6, § 14, Gerhardt, 5, 288, line 14; Erdrnann, 
313, a; Jacques, 1, 234. The term "species," in Leibnitz's day, denoted not 
merely similarity of external form and characteristics, but more essentially 
the genetic relationship of common descent. — Tr. 



ch. m] ON HUMAN UNDERSTANDING 315 

§ 15. Ph. The species of each thing is ordinarily supposed 
to have a real constitution, and it is beyond doubt that some 
real constitution must exist upon which every collection of 
simple ideas or qualities co-existing in this thing must depend. 
But as it is evident that things are ranked in sorts or spiecies 
under certain names only as they agree with certain abstract 
ideas to which we have attached these names, the essence of 
each genus or species comes thus to be nothing else than the 
abstract idea signified by the general or specific name, and we 
shall find this to be the import of the word essence, according 
to its most ordinary use. It would not be a bad thing, in my- 
opinion, to designate these two kinds of essences by two 
different names, and to call the one real, and the other, nominal 
essence. 

Th. [It seems to me that our language makes extreme inno- 
vations in the method of expression. We have indeed spoken 
hitherto of nominal and causal or real definitions, but not 
within my knowledge of essences other than real, at least by 
nominal essences have not been understood false and impos- 
sible essences, which appear to be essences, but are not; as, 
for example, would be that of a regular decahedron, i.e. of a 
regular body comprised within ten planes. 1 Essence is at 
bottom nothing less than the possibility of that which we 
think. What we assume as possible is expressed by the defi- 
nition ; but this definition is only nominal when it does not 
express at the same time, possibility ; for then we may doubt 
whether this definition expresses anything real, i.e. possible, 
until experience comes to our aid to make us know this reality 
a posteriori, 2 when the thing is actually found in the world : 
and this suffices for the defect of the reason, which made us 
know the reality a priori 2 by exposing the cause or the possible 
generation of the definite thing. It does not then depend on 
us to unite ideas as seems good to us ; at least, this combination 
is not justified either by reason which shows it as possible, or 
by experience which shows it as actual, and consequently, also 
possible. In order the better to distinguish, also, essence and 

1 This figure is impossible, the only possible regular polyhedrons being 
the tetrahedron, hexahedron, octohedron, dodecahedron, and icosahedron. — 
Tr. 

2 Cf. ante, p. 227, note 2. — Tr. 



316 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

definition, you must consider that there is only one essence of 
the thing, but that there are many definitions which express 
one and the same essence, as the same structure or the same 
city may be represented by different scenographies according 
to the different sides from which it is regarded.] 

§ 18. 1 Ph. You will, I think, agree with me that the real 
and the nominal are always the same in simple ideas and in 
the ideas of the modes ; but in the ideas of substances, they 
are always entirely different. A figure which bounds a space 
by three lines is the real as well as the nominal essence of 
the triangle ; for it is not only the abstract idea to which the 
general name is annexed, but the essence or proper being of 
the thing, or the foundation whence proceed its properties, 
and to which they are annexed. But it is wholly otherwise 
as regards gold. The real constitution of its parts, upon which 
its color, weight, fusibility, firmness, etc., depend, is unknown 
to us ; and, having no idea of it, we have no name that is its 
sign. Yet these are the qualities which cause the matter to 
be called gold, and are its nominal essence, i.e. which give it a 
right to the name. 

Th. [I should prefer to say, in accord with received usage, 
that the essence of gold is that which constitutes it and which 
gives it these sensible qualities, which make it known and 
which make its nominal definition, while we should have the 
real and causal definition if we could explain this contexture 
or internal constitution. But the nominal definition is here 
found real also, not by itself (for it does not make known 
a priori the possibility or the genesis of bodies), but by experi- 
ence, because we have experience of a body in which these 
qualities are found together : but without this we might doubt 
whether so much weight would be compatible with so much 
malleability, as it may be doubted, even at present, whether a 
glass malleable by cold is possible in nature. 2 I am not, for 
the rest, of your opinion, sir, that there is here the difference 

1 § 18, in Locke, Philos. Works, 2, p. 19 (Bonn's ed.) ; so Gerhardt : Erdmann, 
Jacques, and Sckaarsclimidt in his German translation, have § 19. — Tk. 

2 Gf. Pliny the Elder, 23-79, Histor. Natur., Bk. 36, chap. 66; Eng. trans. 
(Bohn's Class. Lib.), Vol. 6, p. 381, London, 1857. " In the reign of Tiberius, 
it is said, a combination was devised which produced a flexible glass. . . . This 
story, however, was, for a long time, more widely spread than well authenti- 
cated " — " fama crebrior quam certior." — Tk. 



en. in] ON HUMAN UNDERSTANDING 317 

between the ideas of substances and the ideas of predicates, as 
if the definitions of predicates (i.e. of the modes and the 
objects of simple ideas) were always real and nominal at 
the same time, and that those of substances were only nominal. 
I quite agree that it is more difficult to have real definitions 
of bodies, which are substantial existences because their con- 
texture is less sensible. But it is not the same with all sub- 
stances ; for we have a knowledge of true substances or unities 
(as God and the soul) as intimate as we have of the most of 
the modes. Besides, there are some predicates as little known 
as the contexture of bodies ; yellow or bitter, for example, 
are objects of simple ideas or notions (phantasies 1 ), and yet we 
have only a confused knowledge of them. 2 The case is the 
same in mathematics, where one and the same mode may have 
a nominal as well as a real definition. Few people have 
clearly explained in what consists the difference between these 
two definitions which must distinguish, also, essence and prop- 
erty. In my opinion, this difference is that the real shows 
the possibility of the thing defined, and the nominal does not. 3 

1 Schaarschmidt translates : " die Gegenstande einfacher Vorstelhmgen oder 
Phantasiebilder." — Tr. 

2 Of. New Essays, Preface, ante, p. 48, ad fin, and Bk. IV., chap. 6, § 7, Th. 
(2) , infra, p. 458. According to Leibnitz, sense-knowledge is confused, and needs 
to be developed into clearness and consistency by the discriminative analysis 
and unifying power of thought. Phenomena such as colors, sounds, etc., the 
subjective counterpart or resultant of specific sense-energies, resist all further 
analysis, and while clear as wholes, are composite, insoluble, and so confused 
as regards their single elements. Such wholes admit only descriptive, not, 
strictly speaking, logical definition. Of. Med. de Cog., Ver., et Id. ad init., 
Gerhardt, 4. 422, Erdmann, 78, a, trans. Duncau, Philos. Works of Leibnitz, 27. 
— Tr. 

3 Of. ante, pp. 17, 201, and Med. de Cog., Ver., et Id., Gerhardt, 4, 424, 
Erdmann, 80, b, trans. Duncan, Philos. Works of Leibnitz, 30; also G. 6, 
405, E. 637, a, Dutens, Leibnit. opera omnia, 1, 439 ; 6, 44 ; G. 7. 194 and note. 
As the nominal definition explains a thing according to the name, we may have 
nominal definitions of objectively non-existent or of impossible things, as 
centaurs, griffins, or any of the creatures of the fancy or the imagination, or 
the decahedron mentioned in § 15, Th., of this chapter, ante p. 315. The real 
definition explains the thing to be defined by exhibiting its cause or generation, 
its rise out of its conditions, i.e., its possibility; it is thus identical with the 
genetic definition, and Leibnitz accordingly calls it the causal definition, ante 
p. 316. Of. also Dewey, Leibniz's New Essays, 210; Hamilton, Logic, 343; 
Trendelenburg, Ueber d. Element d. Definition in Leibniz. Philosophie in 
Histor. Beitr. z. Philos., Berlin, 1867, Vol. 3, pp. 48-62. Trendelenburg calls 
special attention to the fact that Leibnitz, in definition, has in mind especially 
the analytical element, explaining definition as an unfolding of the concept, 



318 LEIBNITZ'S CEITIQUE OF LOCKE [bk. hi 

The definition of two parallel straight lines, which states that 
they are in one and the same plane and will not meet although 
continued to infinity, is only nominal, for we could at once 
doubt whether that is possible. But when we have under- 
stood that we can draw a straight line in a plane parallel to 
a given straight line provided we take care that the point of 
the style describing the parallel remains always equally distant 
from the given line, we see at once that the thing is possible, 
and why they have this property of never meeting, which con- 
stitutes their nominal definition, but which is the sign of the 
parallelism only when the two lines are straight, while if one 
at least were curved, they might be by nature unable ever to 
meet, and yet not on that account be parallel. 

§ 19. Ph. If essence was something else than the abstract 
idea it would not be ingenerable 1 and incorruptible. A uni- 
corn, a mermaid, a perfect circle, perhaps do not exist in the 
world. 

Tli. [I have already told you, sir, that essences are perpetual, 
because here the question concerns only the possible.] 



CHAPTER IV 

OF THE NAMES OF SIMPLE IDEAS 

§ 2. Ph. I confess I have always believed that the forma- 
tion of the modes was arbitrary ; but as regards simple ideas 
and those of substances, I have been persuaded that, besides 
possibility, these ideas should signify a real existence. 

Tli. [I see no necessity for it. God has ideas before creating 
the objects of these ideas, and nothing prevents Him from 
being able also to communicate such ideas to intelligent creat- 
ures : there is also no exact demonstration proving that the 
objects of our senses and of the simple ideas which the senses 

or its resolution into several concepts equivalent to the one concept — " definire 
est explicare notionem, resolvere in plures notiones uni aequivalentes ; " cf. 
Dutens, op. cit.,i, 68 : " definitio nihil aliud, quam accurata nominis explicatio 
est"; G. 4, 140, E. 60, h : "definitio enim nihil aliud est, quam significatio 
verhis expressa, sive brevius, significatio significata." — Tr. 

1 Locke's word, Philos. Works, Vol. 2, p. 20 (Bohn's ed.). — Tr. 



ch. iv] ON HUMAN UNDERSTANDING 319 

present to us are outside us. 1 This fact has especial weight 
in the case of those who believe with the Cartesians and with 
our distinguished author, that our simple ideas of sensible 
qualities have no resemblance to that which is outside us in 
the objects ; there would then be nothing requiring these ideas 
to be grounded in any real existence. 2 ] 

§§ 4, 5, 6, 7. Ph. You will grant me at least this other 
difference between simple and complex ideas, that the names 
of single ideas cannot be defined, while those of complex ideas 
can be. For definitions should contain more than one term, 
each of which signifies one idea. Thus you see what can or 
cannot be defined, and why definitions cannot go on to infinity ; 
a remark which no one, so far as I know, has up to this time 
made. 

Th. [I have also made the statement in the brief Essay 
upon Ideas* inserted in the " Actes de Leipzic " about twenty 
years since, that simple terms cannot have nominal definitions ; 
but I have there added at the same time the statement that 
terms, when they are simple only as regards us (because we 
have no means of analyzing them so as to reach the elementary 

1 The demonstrability of the reality of that which lies at the hasis of the 
phenomena of the senses is one of the most difficult prohlenis in the theory of 
knowledge — Erkenntnisslehre. Leibnitz seems nowhere to have discussed the 
question, at least in this form, nor to have asked himself how, agreeably to 
his philosophical system, a knowledge of the reality of the external world 
could he demonstrated or a belief therein justified. So far as his system sug- 
gests any answer consistent with itself, that answer is found in his doctrine of 
pre-established harmony, in the consciousness of which we pass immediately 
from our inner representative world of ideas to belief in the reality of the 
external things thus ideally represented. This, however, like Descartes' 
attempt to bridge the chasm from the subjective to the objective by his doctrine 
of God's veracity, is mere assumption, not " exact demonstration." The 
problem belongs to both psychology and metaphysics, and is satisfactorily 
discussed and solved only when considered in these two aspects. Leibnitz was 
an idealist in psychology, and a realist in metaphysics, and never really har- 
monized or united these two points of view. For him, therefore, there could 
be "no exact demonstration" of tbe external reality of "the objects of our 
senses and of the simple ideas which the senses present to us." Of. Discours 
de Metaphysique, §§ 26 sq., Gerhardt, Leibniz, philos. Schrift., 4. 451 sq., E. 
Caird, The Crit. Philos. of Immanuel Kant, 1, 86-95. New York, Macmillan 
&Co., 1889. — Tb. 

2 Of. New Essays, Bk. II., chap. 8, §§ 21, 24, ante, pp. 133-135 ; also Bk. IV., 
chap. 11. The constancy of sense-phenomena is the constraining reason for 
referring them to something real. Cf. Dewey, Leibniz's Neio Essays, 173 sq.; 
Gerhardt, Leibniz, philos. Schrift. 7, 319 sq. — Tu. 

3 Cf. ante, p. 14, note 2 ; p. 227, note 3. — Tr. 



320 LEIBNITZ'S CKITIQUE OF LOCKE [bk. hi 

perceptions of which they are composed), as heat, cold, yellow, 
green, can receive a real definition which would explain their 
cause. Thus, the real definition of green is that of an entity 
composed of "blue and yellow thoroughly mixed, 1 although 
green is no more susceptible of a nominal definition by which 
we may recognize it than blue or yellow. Terms on the other 
hand which are simple in themselves, i.e. whose conception is 
clear and distinct, cannot receive any definition, whether 
nominal or real. You will find in this little Essay, placed in 
the "Actes de Leipzic," the foundations of a large part of 
the doctrine concerning the understanding, briefly explained.] 

§§ 7, 8. Ph. It were well to explain this point and to indi- 
cate what can be defined, what not. And I am tempted to 
believe that often great disputes are raised and much nonsense 
introduced into men's discourse from a failure to consider this 
matter. These celebrated trifles about which so much stir is 
made in the schools have arisen from the fact that no attention 
has been paid to this difference which is found in ideas. The 
greatest masters in the art have been constrained to leave 
the majority of simple ideas without defining them, and when 
they have undertaken to define them, they have not succeeded. 
"What more superfine nonsense, for example, could the mind of 
man invent than that which is contained in this definition 
of Aristotle : Motion is the realization of that which is possible 
so far as it is possible ? 2 § 9. And the moderns who define 
motion as passage from one place into another, merely put one 
synonymous word in the place of another. 

Th. [I have already remarked in one of our past conferences 
that you consider many ideas as simple which are not so. 
Motion is of this number which I believe to be definable ; and 
the definition which states that it is a change of place is not 
to be despised. Aristotle's definition is not so absurd as you 

1 This is true of pigments, but not of lights. Blue and yellow lights when 
mixed produce white light. — Tk. 

2 Cf.Neio Essays, Bk. II., chap. 21, § 1, Th. ante,?. 174. For Aristotle's 

definition, cf. PhyS. AcrOUS., III., 1, 201b, 4 : i, tov Swarov, 77 Swarov, ivTe\ix eia 
(fravzpbv on kiVijcti's eo-riJ', 201% 11 : V no Swa^ei ovto? evTeAe'xeia, 77 toioutoj', Klvricrls 
iariv, MetaphyS. K, 9, 1065 15 , 16 : tt)v toO Svvajiti 77 tolovtov eo-nv ivepyiav Ae'yto 
KtVrja-iv, 23 • V &*l T0 " ovva/uei ovtos, brav evreAe^et'a ov evepyrj 17 avrb rj 0.W0 77 kivt\t6v, 

KLvritrk ecrTLv, also 33 ; Wallace, Outlines of the Philos. of Aristotle, § 42, p. 77; 
Zeller, Philos. d. Griec, 3d ed., 1879, II., 2 [Vol. 4], p. 350 sq., with the notes. 
— Ta. 



ch. iv] ON HUMAN UNDERSTANDING 321 

think., this supposed absurdity arising from the failure to 
understand that the Greek klvvo-l's with him did not signify 
what we call motion, but what we would express by the word 
change, whence it comes that he gives it a definition so abstract 
and metaphysical, while what we call motion is called by him 
cjiopd, latio, and is found among the species of change (t^s 

Ktvrjaews : ).] 

§ 10. Ph. But you will not apologize, at least, for the same 
author's definition of light as the action of the transparent. 2 

Th. [I find it, as you do, very useless ; 3 and he makes too 
frequent use of his action, which does not tell us much. 
Diaphanous is for him a medium across which we can see; 
and light is, according to him, that which consists in the 
actual passage. Well and good.] 

§ 11. Ph. We agree, then, that our simple ideas cannot 
have nominal definitions, as we cannot know the taste of pine- 
apples by the accounts of travellers, unless able to taste things 
by the ears, as Sancho Panza had the power to see Dulcinea by 
hearsay, 4 or as that blind man who, having been heard to speak 
boldly of the brilliancy of scarlet, thought it must resemble 
the sound of the trumpet. 

Th. [You are right; and all the travellers in the world 



1 Cf. PhyS. AcrOCiS., VII. 2, 243 a , G Sq. : errel Si rpets eio-l Kti/rjcrety, iq re Kara tottov 
koX Kara to ttolov /cat Kara, rb ttoo~6v , dp ayKT] /cat Ta Kivovfxeva Tpt'a. y) ju.ep ovv Kara tottov 
(j>opa, r) Si Kara to ttolov aAAot'tdcris, 17 Se Kara to 7too-6p av|i)o-t; /cat c/>St'cri?, Eth. Nic. X., 

3, 1174 a , 30: « ydp la-nv 17 <popa /ainjcris jr69ei> Trot (Alex. Grant, The Ethics of 
Aristotle, Vol. 2, p. 324, line 17, 3d ed., London: Longmans, Green, & Co., 
1874); Wallace, Outlines, § 42; Zeller, Philos. d. Griec., 3d ed., 1879, II., 2 
[Vol.4], p. 389 s<?. — Tk. 

2 Cf. De Anima, II., 7, 418 b , 9: <pws Se io-nv ^ tou'tou evepyeia tov Sta^otpous y 
Stcupave's, 419 a , 11 : h 5' evTeAexeta tou Siafyavovs (^cls ecrTtV. E. Wallace, Aristotle's 

Psychology in Greek and English w. Introd. and Notes, Cambridge : Univ. 
Press, 1882, pp. 95, 97, translates the two passages : " Light then is the expres- 
sion of the pellucid qua pellucid," "The full play of this pellucid constitutes 
light," and, in his Introd., p. lxxi., combines them thus : " Light therefore may 
itself be defined as the actual expression or full play of the pellucid as pellucid." 
Cf. also Zeller, Philos. d. Griec:, 3d ed., 1879, II., 2 [Vol. 4], p. 477, note 2. 

3 Schaarschmidt calls attention to " a bad typographical error" in the text 
of Raspe's edition of the Nouveaux Essais at this point. Raspe reads "fort 
uMle," for which Schaarschmidt proposes " futile." Gerhardt, Erdmann, and 
Jacques all read " fort inutile," which gives the requisite sense, and is accord- 
ingly followed in the translation. — Tr. 

4 Cf. Cervantes, 1547-1616, Don Quixote, Pt. 2, chap. 9, ad med. ; also, Pt. 1, 
chap. 31. — Tr. 

Y 



322 LEIBNITZ'S CRITIQUE OE LOCKE [bk. in 

could not give by their words what we owe to a gentleman 
of this country who cultivates successfully pine-apples three 
leagues from Hannover, almost upon the bank of the Weser, 
and who has found means of multiplying them to such an 
extent that some day we can perhaps have them of our own 
growing in as great abundance as the oranges of Portugal, 
though there would apparently be some loss in the flavor.] 

§§ 12, 13. Ph. It is wholly otherwise with complex ideas. 
A blind man can understand what a statue is ; and a man who 
had never seen the rainbow could understand what it is, pro- 
vided he had seen the colors which compose it. § 15. But 
though simple ideas are inexplicable, they are the least doubt- 
ful. [For experience accomplishes more than definition.] 

Th. [There is, however, some difficulty as to the ideas which 
are only simple as regards us. For example, it would be diffi- 
cult to indicate precisely the limits of blue and of green, and in 
general to discriminate colors closely approaching one another, 
while we can have precise notions of the terms used in arith- 
metic and geometry.] 

§ 16. Ph. Simple ideas have further this peculiarity that 
they have very little subordination in what the logicians call 
the line of predication {ligne prklkamentale) , l from the lowest 

1 Leibnitz here refers to the Tabula logica, in which Porphyry, 233-304, and 
after him the Scholastic logicians, such as Lambert of Auxerre, c. 1250, Petrus 
Hispanus, c. 1226-1277, Raimund Lulli, 1234-1315, the Pseudo-Thomas, and 
Johannes Majoris Scotus, 1478-1540, sought, in connection with the live pre- 
dicables, to arrange in strict logical subordination by the process of dicho- 
tomic or bifurcate division, all genera and species from the highest genera to 
the lowest species, between which is found the scale of subordinate notions 
which are at the same time both genus and species. This Tabula logica was 
called by the later commentators, who added the diagram illustrating it, not 
found in Porphyry, the arbor Porphyriana or the arbor praedicamentalis, and 
the line of subordination from the highest genus to the lowest species was called 
the linea praedicamentalis or praedicabilis, or the ordo praedicamentalis. Cf. 
Porphyry, Eio-aywyi? chap. 2, 1 b. 40 sq. (in Aristotle, ed. Berl. Acad., Vol. 4, 
p. 1) ; 'E£ij 7 r,o- t 9, f. 18 b., Paris, 1543, 4to ; Prantl, Gesch. d. Logik im Abend- 
lande, Leipzig, 1855-1870, Vol. 1, pp. 627-8, note 41, 633-4, note 67, Vol. 3, pp. 
28, note 14: " Praedicamentum autem nihil aliud est, quam ordinatio prae- 
dicabilium in linea praedicabile secundum sub et supra et a latere et in linea 
recta, . . . unde ilia tota ordinatio, quae est inter genus generalissimum et 
speciem specialissimam et genera subalterna et differentias collaterales, voca- 
tur unum praedicamentum, sicut patet in arbore Porphyrii in tractatu Prae- 
dicabilium." (Lambert of Auxerre, Summa logicae, Paris, MS., Cod. Sorbonn. 
1797), 46, note 168, 151, note 42, 252, note 315, cf. n. 311, Vol. 4, p. 249, note 
434 ; also, Jevons, Elementary Lessons in Logic, p. 103 sq. — Tr. 



ch. iv] ON HUMAN UNDEKSTANDING 323 

species to the highest genus. The reason is that the lowest 
species being only a simple idea, nothing can be taken from 
it ; for example, nothing can be taken from the ideas of white 
and red in order to retain the common appearance in which 
they agree. For this reason, they are included with yellow 
and others, under the genus or the name, color. And when 
men wish to frame a still more general term, comprising, also, 
sounds, tastes, and tangible qualities, they avail themselves of 
the general term, quality, in the sense ordinarily given it to 
distinguish these qualities of extension, number, motion, pleas- 
ure, and pain, which act upon the mind and introduce into it 
their ideas by more than one sense. 

Th. [I have something more to say upon this remark. I 
hope that here and elsewhere you will do me the justice, sir, 
to believe that this is not from a spirit of contradiction, 
and that the subject seems to demand it. It is not an advan- 
tage that the ideas of sensible qualities have so little subordina- 
tion and are capable of so few subdivisions ; for it arises only 
from the fact that we know little of them. But the fact itself 
that all colors have the common property of being seen by 
the eyes, of all passing into bodies from which one or more 
of them reappear, and of being reflected from the polished 
surfaces of bodies which do not allow them to pass, shows us 
that something can be taken from the ideas we have of them. 
Colors may indeed be divided with good reason into extremes 
(one of which is positive, viz. white ; and the other privative, 
viz. black) ; and into means, which are called colors, 1 however, 
in a particular sense, and which spring from light by refrac- 
tion ; which furthermore may be subdivided into those of the 
convex side, and those of the concave side of the broken ray. 
And these divisions and subdivisions are of not a little conse- 
quence.] 

Ph. But how can you find genera in simple ideas ? 

Th. [As they are simple only in appearance, they are 
accompanied by circumstances which are bound up with them, 

1 Gerhardt reads: "et en moyens qu'on appelle encor couleurs dans un 
sens particulier et qui naissent de la lumiere par la refraction ; qu'on peut 
encor," etc. ; Erdmann and Jacques read: " et en moyens qu'on appelle encore 
sous-diviser," etc. ; i.e. and into means which you are further called upon to 
subdivide, etc. — Tr. 



324 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

although this bond is not understood by us, and these circum- 
stances furnish somewhat that is explicable and susceptible 
of analysis, which gives also some hope that hereafter the 
reasons of these phenomena may be discovered. Thus it 
happens that there is a kind of pleonasm in our perceptions of 
sensible qualities, as well as sensible masses ; and this pleonasm 
is, that we have more than one notion of the same subject. 
Gold may be defined nominally in several ways ; you may say 
that it is the heaviest of our bodies, that it is the most malle- 
able, that it is a fusible body which resists the cupel and aqua 
fortis, etc. Each of these marks is good and is sufficient for 
the recognition of gold, at least provisionally and in the present 
state of our bodies, until a heavier body is found, as some 
chemists maintain is the case in their philosopher's stone, or 
until that Luna fixa x is shown, which is a metal said to have 
the color of silver, and almost all the other qualities of gold, 
and which Chevalier Boyle 2 seems to say he has produced. 
Thus you may say that in matters which we - know only 
empirically, all our definitions are merely provisional, as I 
believe I have already remarked above. It is then true that 
we do not know demonstratively whether a color may not pos- 

1 Cf Fratris Basilii Valentini Benedictiner Ordens Chymische Schrift., 
Hamburg, 1700, Pt. I., p. 272: "Werm das Gold seiner Anima auch verlustig 
wird / giebt es ein weiss Corpus und einen fixen weissen Gold-Leib / der von 
den sucbenden Studenten / und von den Jiingern der Kunst eiue Luna fixa 
getaufft und genannt wird ; " Pt. II., p. 381, Schluss-Reden Fr. Basilii Valentini, 
Tract. 1, Sectio in., De Magneta vulgi, § 3: "Mit dem Magnet und Antimonio 
wird aucb eine Luna fixa gemacbt / welcbe alsdann durcb das Oleum Martis 
& Veneris gradirt [sic] , und zu Gold gemacht wird : Jedocb kan mans mit 
Antimonio und Eisen aucb verricbten." Martin Ruland, lexicon alchemize, 
Francofurti, 1612, p. 308: "Luna compacta est argentum fixum vel aurum 
album: Silber fix oder weiss Gold." Robert Boyle, Works, ed. Bircb, 5 vols., 
fol. : London, 1744, Vol. 1, p. 215 ; 2d ed., 6 vols., 4to : London, 1772, Vol. 1, p. 
335, Vol.3, p. 28. — Tr. 

2 Robert Boyle, 1627-1691, a distinguished natural philosopher and chemist, 
the discoverer of the law of the compressibility of gases, which, confirmed by 
its independent discovery by Mariotte in 1676, has since been known as 
" Boyle and Mariotte's Law." He was one of the founders of the Royal Society 
of London, and by his will established the " Boyle Lectures." Leibnitz often 
refers to him, cf. New Essays, Preface, ante, p. 47. — The title of Boyle's work 
there referred to is, Of Absolute Rest in Bodies, Works, ed., Birch, 6 vols., 
4to, London, 1772, Vol. 1, pp. 443-457, in which he opposes the doctrine with 
convincing reasons; — Bk. IV., chap. 12, § 13, Th., infra, p. 526; Gerhardt, 
Leib.niz philos. Schrift., 7, 342 ; Dutens, Leibnit op. om., 5, 98; 6, 107; Leib- 
nitz's estimate of his experiments, 6, 318; Eulogy, 6, Pt. II., 217. — Tr. 



ch. v] ON HUMAN UNDERSTANDING 325 

sibly be produced by reflection alone without refraction, and 
whether the colors we have hitherto noticed in the concavity 
of the angle of ordinary refraction are not found in the con- 
vexity of a kind of refraction hitherto unknown, and vice versa. 
Thus the simple idea of blue would be stripped of the genus 
which we have assigned it in our experiences. But it is well 
to stop at the blue we have and at the circumstances attending 
it. And it is something that they furnish us the means of 
making genera and species.] 

§ 17. Ph. But what say you of the remark that has been 
made that simple ideas, since they are taken from the existence 
of things, are nowise arbitrary, while those of the mixed modes 
are wholly so, and those of substances to some extent ? 

Th. [I believe that the arbitrary quality is found only in 
the words, and not at all in the ideas. For they express 
only possibilities. Thus, if there had never been a parricide, 
and if all the legislators had been as cautious as Solon in 
speaking of it, parricide would be a possible crime, and its 
idea would be real. For ideas are in God from all eternity ; 
and indeed they are in us before we actually think of them, 
as I have shown in our previous conversations. 1 If any one 
wishes to take them as the actual thoughts of men, it is per- 
mitted him to do so, but he will oppose himself without reason 
to the accepted language. 



CHAPTEB V 

OF THE NAMES OF MIXED MODES AND RELATIONS 

§§ 2, 3, seq. Ph. But does not the mind form mixed ideas 
by bringing together simple ideas as suits its purpose, without 
the need of a real model; while simple ideas arise for it 

1 Of. Nero Essays, Preface, ante, p. 42, sq., Bk. I., chap. 1, § 1, sq., ante, 
p. 70, sq., where Leibnitz develops more fully the thought repeated here. 
Leibnitz assumes that ideas — the pure truths of reason— exist in man, and 
come into consciousness by the self-development of the spirit. These ideas 
contain in themselves the potential representation of all possible reality, the 
realization of which is directly proportional to the measure of man's self- 
development. In God this realization is complete, since in his thought all 
real possibility is always actually represented. — Tr. 



326 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

without choice, through the real existence of things ? Is not 
the mixed idea often seen before the existing thing ? 

Th. If you take the ideas as actual thoughts, you are right. 
But I do not see that it is necessary to apply your distinction 
to that which concerns the form itself, or the possibility of 
these thoughts, and yet this is the question in the ideal world 
which is distinguished from the existing world. The real 
existence of beings which are not at all necessary is a matter 
of fact or of history ; but the knowledge of possibilities and 
necessities (for necessary is that the opposite of which is not 
at all possible) constitutes the demonstrative sciences. 1 ] 

Ph. But is there more connection between the ideas of 
killing and of man than between the ideas of killing and of a 
sheep ? Is parricide composed of more connected notions than 
infanticide ? And is it more natural that what the English 
call stabbing, i.e., murder by a thrust, or by striking with the 
point, which is a greater wrong with them than killing by 
striking with the edge of the sword, should have deserved a 
name and an idea which is not accorded, for example, to the 
act of killing a sheep, or of killing a man by cutting ? 

Th. [If the question concerns only possibilities, all these 
ideas are equally natural. Those who have seen sheep killed 
have had an idea of this act in thought, although they have 
not deigned to give it their attention. 2 Why, then, limit our- 
selves to names, when the question concerns ideas themselves, 
and why occupy ourselves with the worth of the ideas of 
the mixed modes, when the question concerns these ideas in 
general ?] 

§ 8. Ph. Men form arbitrarily different kinds of mixed 
modes, so that words are found in one language for which 
there are no corresponding words in another. There are no 
words in other languages corresponding to the word Versura 3 

1 C'f. New Essays, Preface, ante, p. 43. — Tr. 

2 Erdmann reads : " quoiqu'ils ne lui aient point donne de nom et ne l'aient 
point daigne de leur attention;" Jacques reads, after "daigne'," "honorer," 
otherwise like Erdmann. The rendering then is: although they have not 
given it a name, nor have they vouchsafed (to honor — Jacques) it (with) 
their attention. — Tr. 

3 "Versura," literally "a turning round," means, in classical usage, "the 
borrowing of money to pay a debt," a process which resulted simply in 
changing one's creditor, not in extinguishing the obligation. Cf. Cicero, Epist. 



ch. v] ON HUMAN UNDEKSTANDING 327 

used among the Romans, nor to Corban, 1 used by the Jews. 
We boldly translate the Latin words hora, pes, and libra, by 
hour, foot, and pound ; but the ideas of the Romans were very 
different from ours. 

Th. I see that many things which we discussed when the 
question was that of ideas themselves and their kinds, come 
back now, under cover of the names of these ideas. The 
statement is true as regards the names and the customs of 
men, but it changes nothing in the sciences and in the nature 
of things. It is true that he who would write a universal 
grammar would do well to pass from the essence of languages 
to their existence, and compare the grammars of many lan- 
guages. In like manner, an author who should write a univer- 
sal jurisprudence drawn from reason, would do well to unite 
with it the parallel laws and customs of peoples, which would 
be of service not only in practical life, but also in his reflec- 
tions, and would give him occasion to consider many points 
which would otherwise escape him. But in science itself, 
apart from its history or existence, it is of no consequence 
whether people are or are not conformed to the dictates of 
reason.] 

§ 9. Ph. The doubtful signification of the word species makes 
the statement that the species of mixed modes are made by 
the understanding offensive to some people. But I leave it to 
others to consider who fixes the limits of each sort or species, 
for these two words are for me wholly synonymous. 

ad Atticum, 5, 15, 2; Tacitus, Ann., 6, 16. As a proverb, the word means 
"to get out of one difficulty by getting into another." Cf. Terence, Phormio, 
5, 2, 15; Lactantius, 2, 8, 24. — Tk. 

1 "Corban," Hebrew JS"1^, N.T. Kopfiav, i.e. SS>pov ) originally an offering to 
God of any kind, particularly in fulfilment of a vow. The original use was 
in course of time altered by the traditionalists, and the offerer of the gift 
interdicted from usiug it for himself, or giving it to others. The " corban" 
furnished a ready means to any one who wished to relieve himself from any 
inconvenient obligation, as of assisting his parents in poverty or distress ; he 
simply brought his gift to the temple and offered it to God, saying, "Let it 
be coi-ban," and departed free, as he said, from any further responsibility in 
the matter. It was this utter perversion of the spirit of the law, with its 
resultant positive wrong-doing, that Christ so severely rebuked. Cf. Mark 
7:11-13; Matt. 15:5, 6; and H. A. W. Meyer, Krit. JExeg. Kommentar u. d. 
N.T., 6th ed., Gottingen, 1876— I., 2 [Vol. 2], p. 101; I., 1 [Vol. 1], p. 333; 
Smith's Diet, of the ^Bible, ed. Hackett and Abbot, New York, 1877, Vol. 1, 
p. 491.— Tr. 



LEIBNITZ'S CRITIQUE OE LOCKE 



Th. [The nature of things ordinarily fixes the limits of 
species ; for example, of man and beast, of cut and thrust. I 
admit, however, that there are some notions in which the limit 
is truly arbitrary ; for example, the question of determining a 
foot, for, the straight line being uniform and indefinite, nature 
indicates therein no limits. There are also essences, vague 
and imperfect, into which opinion enters ; as when you ask 
how little hair must be allowed a man in order that he be not 
bald. This was one of the sophisms of the ancients, when one 
pressed upon his adversary : 

Dum cadat elusus ratione ruentis acervi. 1 

But the true answer is that nature has not determined this 
notion, and that the opinion has its share therein that there 
are some persons regarding whom it may be questioned whether 
they are bald or not, and that there are some doubtful persons 
who will pass as bald with some and not with others, as you 
remarked that a horse which will be considered small in 
Holland, will pass as a large one in the country of the Gauls. 
There is indeed something of this nature in simple ideas, for 
I just observed that the final limits of colors are doubtful. 
There are also essences truly half-nominal, in which the name 
enters into the definition of the thing ; for example, the degree 
or quality of doctor, chevalier, ambassador, king, is recognized 
when a person has acquired the recognized right to avail him- 
self of this name. And a foreign minister, however complete 
his power and however extended his train, will not pass as 
an ambassador unless his letter of credence gives him the 
name. But these essences and ideas are vague, doubtful, arbi- 
trary, nomincd, in a sense a little different from those which 
you have mentioned.] 

. § 10. Ph. But it seems that the name often conserves the 
essences of the mixed modes which you think are not arbitrary ; 
for example, without the name triumph, we should have but 
little idea of what took place among the Romans upon that 
occasion. 

Th. [I agree that the name serves to call attention to things 
and to conserve the memory and the actual knowledge of them ; 

i Horace, Epist. 2, 1, 47. — Tr. 



CH. v] ON HUMAN UNDERSTANDING 329 

but that accomplishes nothing as regards the point in question, 
nor does it render the essences nominal ; and I do not under- 
stand why you gentlemen absolutely require that the essences 
themselves should depend upon the choice of names. It would 
have been desirable that your distinguished author, instead of 
insisting upon that, had preferred to enter into a much more 
detailed account of ideas and of modes, and to have set them 
in order and developed the varieties. I would have followed 
him on this road with pleasure and with profit. For he would 
doubtless have given us much light.] 

§ 12. Ph. When we speak of a horse, or of iron, we regard 
them as the things which furnish us the original patterns of 
our ideas ; but when we speak of mixed modes or, at least, 
of the most important of these modes, which are moral entities, 
— for example, justice, gratitude, — we consider their original 
modes as existing in the mind. Therefore we say the notion 
of justice, of temperance ; but we do not say the notion of a 
horse, of a stone. 

Th. [The patterns of the ideas of the one are as real as 
those of the ideas of the other. The qualities of the mind 
are not less real than those of the body. It is true you do 
not see justice as you see a horse, but you understand it no 
less, or rather you understand it better ; it is no less in acts 
than directness or obliqueness is in motions, whether you 
consider it or not. And to show you that men are of my 
opinion, and men, indeed, the most capable and most experi- 
enced in human affairs, I have only to avail myself of the 
authority of the Eoman jurisconsults, followed by all others, 
who call these mixed modes or these moral entities, things, 
and in particular, incorporeal things. For servitudes, 1 for ex- 
ample (like that of the passage through the ground of one's 
neighbor), are with them res incorporates, in which there is a 
property which may be acquired by long use, and may be 
possessed and reclaimed. As for the word notion, many clever 
people have considered it as large as that of idea ; Latin usage 

1 Cf. Sandars, Institutes of Justinian, Lib. II., Tit. III., p. 118, 8th ed., 
London: Longmans, Green, & Co., 1888; Poste, Gaius, .Elements of Roman 
Law, Bk. II., 29, 31, pp. 165-6, 3d ed., Oxford, 1890; Mommsen, Digest, Lib. 
VIII., 1, Vol. 1, p. 250, Berlin: Weidmann, 1870; Hadley, Introd. to Roman 
Law, pp. 158-161, 180-196, New York, D. Appleton & Co., 1881. — Tr. 



330 LEIBNITZ'S CRITIQUE OE LOCKE [bk. in 

is not opposed thereto, nor do I know whether that of the 
English or the French is contrary to it. 1 ] 

§ 15. Ph. It is further to be remarked that men learn the 
names before the ideas of the mixed modes ; the name showing 
them that this idea deserves to be observed. 

Th. [This remark is a good one, although it is true that 
now-a-days children, with the aid of nomenclators, ordinarily 
learn the names not only of the modes, but also of substances, 
before the things, and indeed rather the names of substances 
than of the modes; for it is a defect in these same nomen- 
clators that they employ nouns only, and not verbs ; not con- 
sidering that verbs, although signifying the modes, are more 
essential in conversation than the majority of nouns, which 
indicate particular substances. 2 ] 



CHAPTER VI 

OF THE NAMES OF SUBSTANCES 

§ 1. Ph. The genera and species of substances, as of other 
beings, are only sorts. For example, suns are a sort of stars, 
i.e. they are fixed stars, for it is not without reason that we 
think each fixed star would make itself known as a sun to 
a person placed at a proper distance. § 2. Now that which 
limits each sort is its essence. It is known either by its 
interior structure, or by external indications which make us 
recognize it and call it by a certain name : and thus it is that 
we may recognize the clock of Strasburg either as the clock- 
maker who made it, or as a spectator who sees its effects. 

Th. [If this is your statement, I have nothing to oppose 
to it.] 

1 Of. Neiv Essays, Bk. II., chap. 22, § 2, Th. ante, p. 222; Discours de Meta- 
physique, 1686, § 29, Gerhardt, 4, 452. For the meaning and use of these terms : 
in Latin, idea, notio, conceptus or conceptio ; in French, idee, notion, concep- 
tion ; in German, Idee, Vorstellung, Begriff; in English, idea, notion, con- 
ception or concept, which varies according to the period in the history of 
thought in which they are employed, and according to the theory of knowledge 
implicitly or consciously held by the author using them, cf. Krauth-Flemming, 
Vocab.ofthe Philos. Sciences, ed. of 1877, sub voc. — Tr. 

2 "For," as Schaarschmidt says, "the activity is first perceived, and by its 
means the substance recognized and formulated." — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 331 

Ph. I express myself in a way suited uot at all to renew 
our discussions. But I add tliat the essence is. related only 
to sorts, and that nothing is essential to individuals. An 
accident or a disease may change my color or shape ; a fever 
or a fall may take away my reason or memory; apoplexy 
may leave me neither feeling, understanding, nor life. If 
you ask me if it is essential to me to have reason, I reply : 
no. 

Th. [I think that there is something essential to individuals 
and more than you suppose. It is essential to substances to 
act, to created substances to suffer, to minds to think, to bodies 
to have extension and motion. That is, there are some sorts 
or species to which an individual cannot (naturally at least) 
cease to belong, when it has once been of their number, what- 
ever revolutions may happen in nature. But there are some 
sorts or species, which are accidental (I admit) to the indi- 
viduals, which may cease to belong to them. Thus you 
may cease to be healthy, beautiful, wise, and indeed to be 
visible and palpable, but you cannot cease to have life and 
organs and perception. I have stated sufficiently, above, why 
it appears to men that life and thought sometimes cease, 
although they cease not to endure and to have their effects.] 

§ 8. Ph. Many individuals ranked under a common name, 
considered as belonging to one species only, have nevertheless 
very different qualities depending upon their real (particular) 
constitutions. This is easily observed by all those who ex- 
amine natural bodies ; and chemists often are convinced of it 
by sad experience, when they vainly seek in one portion of 
antimony, sulphur, and vitriol for the qualities which they 
have found in other portions of these minerals. 

Th. [No statement has more truth, and I could myself even 
furnish intelligence concerning it. Books have also been written 
expressly de infido experimentorum chymicorum successu. But 
the error consists in taking these bodies as similar or uniform, 
while they are more mixed than we suppose ; for in dissimilar 
bodies we are not surprised to remark differences between 
individuals, and physicians do not know how much the tem- 
peraments and natural dispositions of human bodies differ. 
In a word, we shall never find the final logical species, as I 
have already remarked above, and two real or complete indi- 



332 LEIBNITZ'S CEITIQUE OF LOCKE [bk. hi 

viduals of one and the same species are never perfectly 
alike. 1 ] 

Ph. We do not notice all these differences, because Ave do 
not know the little parts, nor consequently the interior struct- 
ure of tilings. Thus we do not avail ourselves of them in 
order to determine the sorts or species of things, and if we 
wished to do so by means of these essences, or by what the 
schools call substantial forms, we should be like a blind man 
who desired to arrange bodies according to colors. § 11. We 
do not indeed know the essences of spirits, we know not how 
to form distinct specific ideas of angels, although we well 
know that there must be many kinds of spirits. Thus it 
seems that in our ideas we put no difference between God and 
the spirits by any number of simple ideas, save that we attribute 
infinity to God. 

Th. [There is, however, another difference in my system 
between God and created spirits, viz. that in my view all 
created spirits must have bodies, just as our soul has one. 2 ] 

§ 12. Ph. I think at least that there is this analogy between 
bodies and spirits, that as there is no gap in the varieties of 
the corporeal world, so there will be no less variety in intelli- 
gent creatures. Commencing from ourselves and proceeding 
even to the lowest things, a descent is made by very small 

1 Cf. Neto Essays, Preface, ante, p. 51, Bk. II., chap. 27, ante, p. 238 sq. ; 
Be ipsa natura, § 13, Gerhardt, 4, 512, Erclmarm, 158, b, Jacques, 1, 464 (in 
French), trans. Duncan, Philos. Works of Leibnitz, 122, 123 ; Monadologie, § 9, 
G-. 6, 608, E. 705, J. 2, 392, trans. D. 219, F. H. Hedge, "Jour. Spec. Philos.," 

1, 129 ; 4th letter to Clarke, §§ 4 sq., G. 7, 372, E. 755, b, J. 2, 432, trans. D. 247, 
5th letter to Clarke, § 21, G. 7, 393, E. 765, J. 2, 449, trans. D. 258. This is the 
principle of the identity of indiscernibles, principium identitatis indiscerni- 
bilium — i.e. that " things qualitatively undistinguishable are absolutely identi- 
cal." According to Leibnitz, there are no such things, there being in the 
universe no two objects perfectly alike ; though abstractly possible, they are 
inconsistent with the order of things, and with the divine wisdom, which 
admits nothing therein without reason. Cf. also Kant's development and 
criticism of Leibnitz's principles in his Dilucidatio nova, 1755. Werke, ed. 
Rosenkranz & Schubert, Leipzig, 1838-42, Vol. 1, p. 1; ed. Hartenstein, Leipzig, 
1867-68, Vol. 1, p. 365, Krit. d. r. Vernunft, V. d. Amphibolie d. Reflexions- 
bec/riffe, ed. R. & S. 2, 214, ed. H. 3, 225, 4th ed., J. H. v. Kirchmanu, Leipzig, 
1877, p. 268 sq., E. Caird, The Grit. Philos. of Immanvel Kant, 1, 106- sq., 445 
sq., 500 sq., New York, Macmillan & Co., 1889; Ueberweg, Hist, of Philos., 

2, 144, 173, Ueberweg-Heinze, Geseh. d. Philos., 7th ed., 3, 215, 259. — Tr. 

2 Cf. New Essaijs, Preface, ante, p. 52, Bk. II., chap. 1, § 12, Th. ante, p. 113, 
chap. 15, § 4, Th. ante, p. 159, and note. — Tr. 



en. yi] ON HUMAN UNDERSTANDING 333 

degrees, and by a continued series of tilings, which in each 
remove differ very little one from the other. There are fishes 
that have wings, and to whom the air is not strange, and there 
are birds inhabiting the water whose blood is cold like that of 
the fishes, and whose flesh so strongly resembles theirs in 
taste that the scrupulous are allowed to eat them on fish- 
days. There are animals so closely approaching the species 
of birds and of beasts that they hold the middle ground between 
them. The amphibia contain both terrestrial and aquatic ani- 
mals. Seals live upon the land and in the sea; and porpoises 
(whose name signifies sea-hog) have the warm blood and the 
entrails of a hog. Not to speak of that which is reported of 
sea-men, 1 there are some animals who seem to have as much 
knowledge and reason as some that are called men ; and there 
is so close a relation between animals and vegetables, that 
if you take the most imperfect of the one and the most perfect 
of the other, you will scarcely perceive any considerable dif- 
ference between them. Thus, until we reach the lowest and 
least organized parts of matter, we shall find everywhere species 
bound together, and differing only by degrees almost impercept- 
ible. And when we consider the wisdom and infinite power of 
the Author of all things, we have reason to think that it is con- 
formed to the magnificent harmony of the universe and to the 
great design as well as to the infinite goodness of this sovereign 
architect, that the different species of creatures ascend, also, 
little by little from us towards his infinite perfection. Thus 
we have reason to be persuaded that there are many more 
species of creatures above us than below us, because we are 
much more distant in degrees of perfection from the infinite 
being of God than from that which approaches nearest to 
nothing. Yet we have no clear and distinct idea of all these 
different species. 

Th. [I had intended in another place to say something not 
unlike what you, sir, have just set forth ; but I am glad to 
have been anticipated when I see that you state things better 
than I could hope to have done. Clever philosophers 2 have 

1 I.e. mermaids; so Locke, "mermaids or sea-men," Philos. Works, Vol. 2, 
p. 49 (Bonn's ed.). — Tr. 

2 Cf. Theudicee, Pt. I., § 14, Gerhardt, 6, 110, Erdmann, 507, b, Jacques, 
2, 80, Dutens, 1, 131 (in Latin) ; Reply to Bayle, ad Jin., G. 4, 570, E. 190, b, 



334 LEIBNITZ'S CRITIQUE OE LOCKE [bk. in 

discussed this question : utrum detur vacuum formarum, I.e. 
whether there are possible species, which, however, do not 
exist, and which nature may seem to have forgotten. I have 
reason to believe that all possible species are not compossible 
in the universe, great as it is, and that, too, not only in rela- 
tion to things which exist contemporaneously, but also in 
relation to the whole series of things. That is to say, I believe 
that there are of necessity species which have never existed 
and never will exist, not being compatible with this series of 
creatures which God has chosen. But I believe that all things, 
which the perfect harmony of the universe can receive, exist 
therein. That there may be intermediate creatures between 
those which are far apart is in conformity with this same 
harmony, although this is not always in one and the same 
globe or system, arid that which is between two species is 
sometimes so in relation to certain circumstances and not in 
relation to others. Birds, so different from man in other 
things, approach him in speech ; but if monkeys could speak 
like parrots, they would go farther. The law of continuity 1 
declares that nature leaves no gap in the order she follows ; 
but every form or species is not the whole order. As for 
spirits or genii, as I hold that all created intelligences have 
organized bodies, whose perfection corresponds to that of the 
intelligence, or the mind, which is in this body in virtue of 
the pre-established harmony, I hold that in order to gain any 
conception of the perfections of spirits above us, it will be of 
great service to imagine these perfections also in bodily organs 
which surpass our own. It is a case in which the liveliest 

D. 2, 93: "II sepeut cependant, que ce Chevalier ait encor eu quelque bon en- 
thousiasme, qui Fait transports dans ce monde invisible, et dans cette e'tendue 
infinie, dont il parle, et que je crois estre celle des idees ou des formes, dont ont 
parle encor quelques Scholastiques en mettant en question, utrum detur 
vacuum formarum." — Tr. 

1 Cf. New Essaijs, Preface, ante, p. 50, Bk. IV., chap. 16, § 12, Th., infra, 
p. 552; The'odicee, III., § 348, Gerhardt, 6, 321, Erdmann, 605, h, Jacques, 2, 
270; Letter to Bayle, in the " Nouvelles de la Bepublique des Lettres," July, 
1687, G. 3, 52, E. 104, trans. Duncan, Philos. Works of Leibnitz, 33; Letter to 
Arnauld, 1690, G. 2, 136, E. 107, b, J. 1, 444, trans. D. 38. Animadversiones in 
partem generalem Principiorum Gartesianorum, Pt. II., ad Art. 45, G. 4, 375, 
Duncan, 61; Guhrauer, G. W. Freiherr v. Leibniz, eine Biographie, 1, 264, 
and notes, pp. 31-33, a letter to an unknown person, Oct. 16, 1707, containing 
a very clear statement of the principle or law of continuity; translation, 
Appendix, pp. 712-714.— Tr. 



ch. vi] ON HUMAN UNDEKSTANDING 335 

and richest imagination, and, to avail myself of an Italian 
term which I cannot well express otherwise, the invenzione la 
piu vaga, will be most timely in raising ns above ourselves. 
And what I have said in justification of my system of harmony, 
which exalts the divine perfections beyond what we had dared 
to think, will assist us also in having ideas of creatures in- 
comparably grander than we have had hitherto. 

§ 14. 1 Ph. To return for a little to the reality of species 
even in substances, I ask you if water and ice are different 
species ? 

Th. [I, in my turn, ask you if gold melted in the crucible 
and gold cooled in bullion are of one and the same species ?] 

Ph. He does not reply to the question, who proposes an- 
other, 

Qui litem lite resolvit. 2 

But you thereby admit that the reduction of things to species 
relates solely to the ideas we have of them, which suffice to 
distinguish them by names ; but if we suppose that this dis- 
tinction is founded upon their real and internal constitution, 
and that nature distinguishes existing things into so many 
species by their real essences, in the same manner as we 
ourselves distinguish them into species by these or those 
names, we shall be liable to great mistakes. 

Th. There is some ambiguity in the term species, or a being 
of a different species, which causes all this confusion ; and 
when we have removed it, there will no longer be discussion 
save perhaps as regards the name. We may take species 
mathematically and physically. In mathematical strictness 
the least difference making two things in any respect dissimilar, 
makes them different in species. Thus, in geometry, all circles 
are of one and the same species, for they are all perfectly alike, 
and for the same reason all parabolas are also of the same 
species ; but it is not the same with ellipses and hyperbolas, for 
of these there is an infinite number of sorts or species, as 
well as an infinite number of each species. All the numberless 

1 Locke has § 13, Philos. Works, Vol. 2, p. 50. The numbering § 14 in the 
French text of all the editions is an error, as will be seen upon comparing 
the numbering of the next §, also 14, with Locke's text. Here also the texts 
coincide with Locke's. — Tr. 

2 Cf. Horace, Satires, 2, 3, 103. — Tr. 



336 LEIBNITZ'S CRITIQUE OE LOCKE [bk. hi 

ellipses, in which the distance of the foci has the same ratio to 
the distance of the apices, are of-one and the same species ; but 
as the ratios of these distances vary only in size, it follows that 
all these infinite species of ellipses make only one genus, and that 
there are no subdivisions. On the other hand, an oval of three 
foci would have indeed an infinite number of such genera, and. 
would have an infinitely infinite number of species, each genus 
having a number of them simply infinite. In this sense two 
physical individuals will never be perfectly similar, and what is 
more, the same individual will pass from species to species, for it 
is never wholly similar to itself even for more than a moment. 
But the men who establish physical species do not adhere, to 
this strictness, and it depends upon them to say that a mass 
which they can make return to themselves under its first form 
continues to be one and the same species in their view. Thus 
we say that water, gold, quicksilver, common salt, continue 
the same, and are only disguised in ordinary changes ; but 
in organized bodies, or in species of plants and of animals, we 
define species by generation, so that this similarity, which 
comes or may have come from one and the same origin or 
seed, would be of one and the same species. 1 In man, besides 
human generation, we fasten upon the attribute rational animal ; 
and, although there are men who live like beasts all their 
lives, we presume that it is not for want of faculty or principle, 
but that it is through impediments which stand in the way 
of this faculty. But it is not yet determined as regards all 
the external conditions which we wish to regard as sufficient 
to give this presumption. But whatever regulations men 
make for their denominations and for the rights attached to 
names, provided that their regulation is followed or made fast 
and intelligible, it will be founded in reality, and they will 
not be able to imagine species which nature, which includes 
even possibilities, has not produced or distinguished before 
them. As for the interior, although there is no external ap- 
pearance which is not based upon the internal constitution, it 
is nevertheless true that one and the same appearance may 
sometimes result from two different constitutions. But in 



i Cf. New Essays, Bk. III., chap. 3, § 14, Th. (2), ante, p. 314; Dewey, Leib- 
niz's New Essays, p. 215 sq. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 337 

that case there will be something in common, and this is what 
we philosophers call the proximate formal cause. But although 
this should not be, as if according to Mariotte 1 the blue of 
the rainbow had an entirely different origin from the blue 
of the turquoise, unless there were a common formal cause (in 
which opinion I do not at all agree with him), and although 
we should agree that certain apparent natures which make us 
give names have nothing internal in common, our definitions 
would not cease to be grounded in real species ; for the 
phenomena themselves are realities. We can say, then, that 
all which we truthfully distinguish or compare, nature dis- 
tinguishes or makes agree also, although she has distinctions 
and comparisons which we do not know and which may per- 
haps be better than ours. Thus much care and experience is 
yet necessary in order to assign genera and species in a manner 
sufficiently like nature. Modern botanists think that the dis- 
tinctions taken from the forms of flowers most resemble the 
natural order. 2 But they find therein, however, still much 
difficulty, and it would be advantageous to make comparisons 
and arrangements not only upon a single character, like that 
of which I have just spoken, which is taken from flowers, 
and is perhaps the most suitable up to this time for a possible 
system and convenient for learners, but also upon characters 
taken from other parts and relationships of plants : each 
basis of comparison deserving tables of its own ; 3 without 
which we shall allow many subaltern genera, and many com- 
parisons, distinctions, and useful observations to escape. But 
the more thoroughly we examine the generation of species, 
and the more we follow in the classifications the conditions 
which are there requisite, the closer we shall approach the 
natural order. Therefore, if the conjecture of some intelligent 
persons were found true, that there is in the plant besides the 

1 Of. ante, p. 121, note 4. — Tr. 

2 Cf. Dutens, Leibnit. opera omnia, Vol. 2, Pt. II., p. 169 sq., Epistola G. G. 
Leibnitii ad A. C. Gackenholtzium, M. D. De Methodo Botanica, April 23, 
1701. — Tr. 

3 Cf. Mor. Willi. Drobisch, Neue Darstg. d. Logik, 3d ed., Leipzig, 1863, 
p. 141 sq., where the so-called Collateral Distributions or Co-divisions, which 
Leibnitz here calls to mind, and " which are of especial importance in Statis- 
tics," are discussed. Drobisch's work is considered " one of the most perfect 
presentations of the subject-matter from the point of view of formal logic." 
— Tr. 



338 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

seed (la graine) or the recognized seed (la semence) correspond- 
ing to the egg of the animal, another seed which would deserve 
the name masculine, i.e. a powder (pollen, visible very often, 
though sometimes, perhaps, invisible, as the seed (la graine) 
itself is in certain plants) which the wind or other ordinary 
accidents scatter in order to unite it with the seed which comes 
sometimes from one and the same plant, and sometimes, also 
(as in the hemp), from another neighboring plant of the same 
species, which plant consequently will be analogous to the 
male, though perhaps the female is never wholly destitute of 
this same pollen; if this conjecture, I say, were found true, 
and if the mode of generation of plants became better known, 
I do not doubt that the varieties which would be noticed would 
furnish a basis for very natural divisions. And if we had the 
penetration of some superior geniuses and knew enough about 
things, perhaps we should find therein fixed attributes for 
each species, common to all the individuals and always sub- 
sisting in the same living organism, whatever alterations or 
transformations may happen to it, as in the best known of the 
physical species, the human, reason is such a fixed attribute, 
granted to each individual, and never to be lost, although 
it cannot always be perceived. But in default of this knowl- 
edge we avail ourselves of the attributes which appear to us 
most convenient for distinguishing and comparing things, and 
in a word, for recognizing in them species or sorts ; and these 
attributes have always their real grounds.] 

§ 14. Ph. In order to distinguish substantial beings accord- 
ing to the usual supposition, that there are certain essences or 
precise forms of things, whereby all existing individuals are 
naturally distinguished into species, it would be necessary to 
be assured, § 15. first, that nature always proposes, in the 
production of things, to make them participate in certain 
regular and established essences, as models ; and, § 16. sec- 
ondly, that nature always attains this end. But monsters 
give us reason to doubt both. § 17. It would be necessary 
to determine, in the third place, whether these monsters are 
really a distinct and new species, for we find that some of 
these monsters have few or none of those qualities which are 
supposed to result from the essence of that species whence 
they derive their origin, and to which they seem to belong in 
virtue of their birth. 



ch. vi] ON HUMAN UNDERSTANDING 339 

Th. When it is a question of determining whether monsters 
belong to a certain species, we are often reduced to conjecture. 
This shows us that we are not, then, limited to external con- 
siderations, since we should divine whether the internal nature 
(as, for example, reason in man) common to the individuals of 
such a species, still suits (as birth makes us conjecture) these 
individuals, in whom a portion of the external characteristics, 
ordinarily found in this species, is lacking. But our incerti- 
tude nowise affects the nature of things, and if there is such 
a common internal nature, it will or will not be found in 
the monster, whether we know it or not. And if the internal 
nature of any species is not found therein, the monster will be 
of its own species. .But if there were no such internal nature 
in the species under discussion, and if the question was not 
decided by birth either, then the external marks alone would 
determine the species, and monsters would not belong to that 
species from which they deviate, unless taken in a manner a 
little vague and with some latitude ; and in this case, also, 
our trouble in desiring to divine the species would be in vain. 
This is perhaps what you mean by all the objections you make 
to species taken as real internal essences. You ought then to 
prove, sir, that no common internal specific mark exists, since 
the external is wholly missing. But the contrary is found in 
the human species in which sometimes children who have 
some monstrosity reach an age in which they exhibit reason. 
Why, then, could there not be something similar in other 
species ? It is true that for want of knowledge of them we 
cannot avail ourselves of it to define them, but the exterior 
takes its place, although we recognize the fact that it is insuffi- 
cient for an exact definition, and that the nominal definitions 
themselves in these instances are only conjectural ; and I 
have already stated above how sometimes they are only pro- 
visioned. For example, we might find a way to counterfeit 
gold so that it might satisfy all the tests which we have up to 
the present time ; but we might also then discover a new method 
of testing which would give the means of distinguishing natural 
gold from this which is artificially made. . The old journals at- 
tribute both (discoveries) to Augustus, Elector of Saxony ; 1 

1 Augustus I., the brother of Maurice, was Elector 1553-1586, and, according to 
Schaarschmidt, " shared with his wife, Anna of Denmark, the love for alchemy." 
— Tr. 



340 LEIBNITZ'S CEITIQUE OF LOCKE [bk. in 

but I am not the man to guarantee this fact. But if it 
were true, we could have a more perfect definition of gold 
than we have at present, and if artificial gold could be made 
in quantity and cheap, as the alchemists claim, this new proof 
would be important ; for by its means we could preserve for 
the human race the advantage which natural gold gives us in 
commerce by its rarity, while furnishing ourselves with a 
substance which is durable, uniform, easy to divide and to 
recognize, and precious in small volume. I wish to avail 
myself of this occasion to remove a difficulty (see § 50 of the 
chapter, " On the Names of Substances,'' in the author of 
the Essay on Understanding). The objection is made that in 
saying : All gold is fixed, if we understand by the idea of gold 
the mass of certain qualities in which fixedness is comprised, 
we make only an identical and useless proposition, as if we 
said : Fixedness is fixedness ; but if we understand thereby a 
substance given a certain internal essence, of which fixedness 
is a result, we shall not speak intelligibly, for this real essence 
is wholly unknown. I reply that the body given this internal 
constitution is designated by other external marks in which 
fixedness is not comprised, as if any one said : the heaviest 
of all bodies is also one of the most fixed. But all that is 
only provisional, for we might some day find a volatile body, 
as a new mercury, which would be heavier than gold, and upon 
which gold would float, as lead floats upon our mercury. 

§ 19. Ph. It is true that in this way we can never know 
precisely the number of properties depending on the real 
essence of gold unless we know the essence of gold itself. 
§ 21. [But if we limit ourselves precisely to certain properties, 
that will be sufficient to enable us to have exact nominal 
definitions which will serve us for the present, reserving to 
ourselves the privilege of changing the signification of names, 
if any new useful distinction is discovered.] But it is neces- 
sary at least that this definition correspond to the use of the 
name, and be capable of being put in its place. This serves 
to refute those who maintain that extension constitutes the 
essence of body, for when it is said that one body gives an 
impulse to another, the absurdity would be manifest, if substi- 
tuting extension (for body) we should say that one extension 
puts in motion another extension by means of an impulse, for 



ch. vi] ON HUMAN UNDERSTANDING 341 

in addition solidity is necessary. In like manner no one will 
say that reason, or that which makes man rational, makes 
conversation ; for reason does not constitute the entire essence 
of man; there are rational animals who converse with each 
other. 

Th. I think yon are right : for the objects of abstract and 
incomplete ideas are not sufficient to give the subjects of all 
the actions of things. But I think that conversation agrees 
with all minds who can interchange their thoughts. The 
scholastics are greatly troubled regarding the angelic method 
of communication ; but if they would accord the angels subtile 
bodies, as I do, following the ancients, they would experience 
no further difficulty in that regard. 1 

§ 22. Ph. There are some creatures in the world which 
have forms similar to ours, but are hairy and use neither 
language nor reason. There are imbeciles 2 among us who 
have exactly the same form as ourselves, but who are destitute 
of reason, and some of them make no use of language. There 
are some creatures, as it is said, which, with the use of lan- 
guage and of reason and a form similar in every other respect 
to ours, have hairy tails ; at least, it is not impossible that 
there are such creatures. 3 There are others, where the males 
have no beard, and others, where the females have. If you 
ask whether all these creatures are men or not, whether they 

1 Of. New Essaijs, Preface, ante, p. 52, Bk. III., chap. 6, ante, p. 332, note 
2 ; also letters to Des Bosses, Sept. 20, Oct. 4, 1706, Gerhardt, 2, 316, 319, 
Erdmann, 439, 440. — Tr. 

2 Locke has: "naturals," Philos. Works, Vol. 2, p. 53 (Bohn's ed.). — Tr. 

3 The myth of men with tails, here mentioned and accepted as credible by 
Locke, arose either from the superficial observation of African travellers, or 
from their uncritical acceptance and rehearsal of the stories of such Negroes 
as claimed to have seen such beings, assumed by them to be endowed with 
reason, although covered with hair and furnished with tails — stories which 
seem to rest upon a confusion of men with man-like apes, a confusion the 
more naturally suggested as many tribes of negroes regard the apes as rational 
but uncivilized human beings. The myth has been exploded in our day by the 
knowledge furnished by scientific explorers into the interior of Africa (the 
assumed abode of these beings), such as Dr. Georg August Schweinfurth, who 
states that among the tribes of Central Africa the Dyoor, the Niam-niam, and 
the Bongo, 'fasten upon themselves behind, as a part of their dress, the tails 
of animals, as, for example, that of "the quereza monkey (Colobus)," or tails 
"composed of the bast of the Sauseviera." Cf . his Im Herzen von Afrika, 
English trans, by Ellen E. Frewer, 2 vols., New York : Harper & Bros., 1874, 
Vol. 1, pp. 201, 294-6, Vol. 2, pp. 2, 6, 11, 137. —Tr. 



342 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

belong to the human species, it is plain that the question 
refers only to the nominal definition, or to the complex idea 
we have made for ourselves in order to indicate it by this 
name; for the internal essence is absolutely unknown to us, 
although we have reason to think that where the faculties, or 
rather the external figure, are so different, the internal consti- 
tution is not the same. 

. Th. I think we have in the case of man a definition at once 
real and nominal. For nothing can be more internal to man 
than reason, and ordinarily it makes itself well known. There- 
fore the beard and the tail will not be considered in comparison 
with it. A man of the forest, though hairy, will make himself 
recognized ; and it is not the hair of a magot 1 which excludes 
him. Imbeciles lack the use of reason; but as we know by 
experience that reason is often bound and cannot appear, and 
as this happens in the case of men who have exhibited and 
will exhibit reason, we make, probably, the same judgment 
regarding these imbeciles upon other indications, i.e. upon 
their bodily figure. It is only by these signs, united with 
their birth, that we presume that infants are men, and will 
manifest reason ; and we are seldom deceived. But if there 
were rational animals with an external form a little different 
from ours, we should be embarrassed. This shows that our 
definitions, when dependent upon the exterior of bodies, are 
imperfect and provisional. If any one called himself an 
angel, and knew, or knew how to do, things much above us, he 
might be believed. If some one else, like Gonzales, 2 came 
from the moon by means of some extraordinary machine, and 
told us credible things about his native country, he would pass 

1 The Barbary ape. — Tr. 

2 Cf. L' Homme clans la lime, ou le voyage chimCrique fait au monde de la 
lune, nouvellement decouvert par Dominique Gonzales, avanturier Espagnol, 
autrement dit le courier volant, mis en nostre langue par J. B. D. (Jean Bau- 
doin), Paris, 1648, 8vo, pp. 176; reprinted Paris, 16G6, with illustrations, and 
also Paris, 1731, 12mo. Brunet states that this is the French translation of 
Franc. Godwin, The Man in the Moon, or a discourse of a voyage thither by 
Domingo Gonsales, London, 1638, also 1657, etc., 12mo; that it had some suc- 
cess, and that it is supposed that Swift borrowed some passages from it for his 
Gidliver's Travels. Cf. E. A. Poe, Works, New York, 1867, Vol. 1, p. 49, who 
gives, in a note at the end of the story of " The unparalleled adventure of one 
Hans Pfaall," the full title of the French book, together with some account of 
its contents, including the machine of Gonzales. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 343 

as a lunar being, and yet we might accord hirn indigineity and 
the rights of citizenship, with the title of man, entire stranger as 
he would be to our globe ; but if he asked for baptism and 
wished to be received as a proselyte of our law, I think that 
we should see great discussions arise among the theologians. 
And if communication were opened with these planetary men, 
sufficiently approaching ourselves according to Huygens, 1 the 
question would require a universal council in order to know 
whether we ought to extend the care of the propagation of the 
faith even beyond our globe. Many would doubtless maintain 
that the rational animals of these countries, not being of the 
race of Adam, have no part in the redemption of Jesus Christ ; 
but others would perhaps say that we have not sufficient 
knowledge either of the place where Adam has always been, 
or of what has been done with all his posterity, since there 
have been theologians, indeed, who believed that the moon 
was the place of paradise ; and perhaps that with the plurality 
we should conclude for the surest thing, viz., to baptize these 
men upon condition that they be susceptible of baptism; but 
I doubt whether we should ever wish to make them priests 
in the Roman Church, because their consecration would always 
be doubtful, and we should expose the people to the danger 
of a material idolatry, according to the hypothesis of this 
church. Happily the nature of things exempts us from all 
these embarrassments ; but these bizarre fictions are useful in 
speculation, in order rightly to know the nature of our ideas. 

§ 23. Ph. Not only in theological questions, but also on 
other occasions some would perhaps wish to regulate them- 
selves by the race, and to say that in animals propagation by 
the copulation of the male and the female, and in plants by 
means of the seeds, keeps the supposed real species distinct and 
entire. But this would serve only to fix the species of animals 
and vegetables. What must be done about the rest ? And 
even as regards these it is not sufficient, for if history is to be 
believed, women have been gotten with children by magots. 
And here is a new question : Of what species must such a 
production be ? You often see mules and jumarts (see Diction- 

1 Of. ante, p. 150, note 3. Leibnizens u. Huyghen's Briefwechseln, v. E. 
GerlancL Berlin, 1881. — Tr 



344 LEIBNITZ'S CRITIQUE OE LOCKE [bk. hi 

naire Ety mologique de M. Menage a ) , the first begotten by an 
ass and a mare, tlie last by a bnll and a mare. I have seen an 
animal begotten of a cat and a rat, which had visible marks of 
these two animals. 2 Whoever will add thereto the monstrous 
productions, will find that it is very hard to determine species 
by generation ; and if it can only be done by that means, must 
I go to the Indies to see the father and mother of a tiger, and 
the seed of the tea-plant, and could I not otherwise decide 
whether the individuals which come to us are of these species ? 
Th. Generation or race gives at least a strong presumption 
(i. e. a provisional proof) and I have already said that very 
often our signs are only conjectural. The race has sometimes 
been contradicted by the figure, as when the child is unlike 
the father and mother, and the mixture of figures is not 
always the sign of the mixture of races ; for it may happen 
that a female gives birth to an animal which seems to belong 
to another species and that the mother's imagination alone 
has caused this irregularity : to say nothing of what is called 
mola. z But as meanwhile we judge provisionally the species 
by the race, we also judge the race by the species. For when 
a forest child, 4 taken from among the bears, who had many of 
their ways, but who made himself known at last as a rational 
animal, was presented to John Casimir, 5 king of Poland, he 
did not scruple to believe him of the race of Adam, and to 
baptize him under the name of Joseph, although perhaps upon 
the condition, si bajjtizatus non es, according to the usage of 
the Roman church, because he might have been carried off by 
a bear after baptism. We have not as yet sufficient knowledge 

i Cf. Dutens, Leibnit. op. om., 5, 350, 543; 6, Pt. II., 21, Gerhardt, 2, 530, 
539. Gilles Menage, 1613-1692. The first ed. was entitled Origines de la langue 
francoise, Paris, 1650, 4to. A new ed. appeared at Paris, 1694, fol., under the 
name, Dictionnaire Etymologique de la langue francoise, etc.; and this was 
afterwards enlarged and edited hy A. F. Jault, Paris, 1750, 2 vols., fol. — Tr. 

2 An instance of superficial observation and hasty inference, like that of 
the men with tails above mentioned, ante, p. 341, note 3. — Tr. 

3 An amorphous fleshy mass in the uterus. — Tr. 

4 Schaarschrnidt states that J. H. F. Ulrich, in his German trans., with ad- 
ditions and notes, Halle, 1778-80, of Raspe's (Euvres philosoph. latines et fran- 
chises de feu Mr. Leibniz, "gives in a note, p. 139-140, information concerning 
the child of the bears found in the forest, without, however, quoting the source 
of his communications." — Tr. 

5 John II., Casimir V., 1609-1672. He was elected king of Poland in 1614, 
and abdicated in 1688. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 345 

of the effects of the intermixture of animals : and often mon- 
sters are destroyed, instead of being brought up, whilst they 
are seldom long lived. The belief is that mixed animals do 
not multiply ; but Strabo 1 attributes propagation to the mules 
of Cappadocia, and letters from China tell me that in neigh- 
boring Tartary there are race-mules. We see also that the 
mixtures of plants are capable of preserving their new spe- 
cies. 2 We do not always indeed know in the case of animals 
whether it is the male or the female, or both, or neither, 
which determines the species. The doctrine concerning the 
eggs of females which the late Mr. Kerkring 3 made famous, 
seemed to reduce the males to the condition of moist air as 
related to plants, which furnishes seeds with the means of 
pushing and raising themselves from the earth ; following the 
verses of Vergil which the Priscillianists 4 were wont to repeat : 

1 Cf. Geographica, p. 212, ed. Casaubon, 1620; Bk. V., chap. 1, § 4, ed. by 
Gustav Kramer, Berlin, 1844-52, 3 vols., 8vo; English trans. Vol. 1, p. 316 
(Bonn's Class. Lib.), London, 1887. — Tr. 

2 Cf. C. Darwin, 1809-1882, Origin of Species, and the new inquiries and 
investigations consequent upon it. — Tr. 

3 Theodore Kerkkrinck, 1640-1693, a Dutch physician, born at Amsterdam, 
died at Hamburg, a fellow-pupil with Spinoza, 1632-1677, of a physician, 
Francis Van der Ende, and author of works on medicine, anatomy, and chem- 
istry, among which was the one here referred to by Leibnitz : Anthropogenic 
ichnographia sive conformatio fostus ab ovo usque ad ossificationis principia, 
in supplernentum osteogenic foztuum, 4to, Amstelodami, 1671. His Opera 
omnia anatomica, 2d ed., 4to, Lugd. Bat., 1717. Of. Dutens, Leibnit. op. om., 
5, 173, 199; F. Pollock, Spinoza: His Life and Philosophy, p. 13. — Tr. 

4 The Priscillianists were an heretical sect which appeared in Spain toward 
the close of the fourth century, and continued till about the middle of the 
sixth. Their speculative doctrines are a combination of Christianity with 
Gnosticism and Manichseism. Their moral system was rigidly ascetic, and 
celibacy was required. The charges of immorality and licentiousness so fre- 
quently brought against them by their adversaries, "are, to say the least, not 
sufficiently well authenticated." The information that they made use of these 
verses of Vergil, to which they attached a religious dogma, as a foundation 
for their heresy and alleged sexual license comes from a letter of Jerome, 
c. 346-420, to Ctesiphon, Epist. 133 ad Ctesiphontem, Opera, ed. Vallarsi, 
Verona?, 1734-42, Vol. 1, p. 1029, a; 2d ed., Venetiis, 1766-72; J. P. Migne, 
Patrol, s. Lat., Vol. 22, p. 1150-51, Paris, 1845, latest ed., Paris, 1864-66. Cf. 
also Sulpicius Severus, 363-406, or 410, Histor. Sacra, or Chronica, Bk. II., 
chaps. 46-51, and Dialog., III., 11-13, ed. C. Halm, Vienna, 1866 (Vol. 1 of the 
Corpus Script. Eccles. Latinorum), and J. Bernays, Die Chronik des Sulp. 
Severus, Berlin, 1861; A. Neander, Hist, of the Christ. Relig. and Church, 2, 
771-779, Boston, Houghton, Mifflin & Co. ; Gibbon, Decline and Fall, Milman's 
ed., chap. 27 ; Smith and Wace, Diet, of Christ. Biog., 4, 470-478, London, John 
Murray, 1887.— Tr. 



346 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

Cum pater omnipotens fcecundis imbribus aether. 
Conjugis in lsetse gremium descendit et oumes 
Magnus alit rnagno commistus corpore foetus. 1 

In a word according to this hypothesis the male would no 
longer be more than the rain. But Leeuwenhoek 2 has reha- 
bilitated the masculine genus, and the other sex is in its turn 
degraded, as if it performed only the earth's function as 
regards seeds, by furnishing them place and nourishment; a 
view which might obtain even if we still maintained the 
theory of the eggs. But this does not prevent the imagination 
of the female from having a great influence upon the form 
of the foetus, even if we supposed that the animal has already 
come from the male. For this is a condition destined ordi- 
narily to a great change, and much more susceptible also to 
extraordinary changes. It is asserted that the imagination of 
a woman in this condition, who was shocked by the sight of a 
cripple, caused the separation of the hand of the foetus very 
near its term, and that this hand was subsequently found in 
the after-birth; a statement, however, which requires confir- 

i Georg., 2, 325-327. — Tb. 

2 Antoon van Leeuwenhoek, 1632-1723, a distinguished Dutch naturalist, 
"the father of scientific microscopy," who shares with Malpighi, 1628-1694, 
the discovery of the capillary circulation of the blood, thus completing the 
doctrine of Harvey, 1598-1657, and with his own pupil, Ludwig Hamm, the 
discovery of the active moving constituents of the seminal fluid, which he called 
"animalcula spermatica," or "spermatozoa." Leeuwenhoek communicated 
his discovery, 1677, of the spermatozoa in a letter to Sir Christopher Wren, 
1631-1723, President of the Royal Society, 1681, " De ovario, et imaginovis ejus 
ovis; homo ex animalculo oritur." The letter is found in Leeuwenhoek's 
Arcana naturse detecta sive epistolai ad societatem Regiam Angliam scriptse, 
Delft, 1695, 4to, p. 28 sq. Leeuwenhoek strenuously opposed the doctrine of 
"spontaneous generation," and did more than any other naturalist to over- 
throw it. Cf. Dutens, Leibnit. op. om., 5, 173, 174, 319, 337; 6, Pt. I., 211, 213, 
218, Gerhardt, Leibniz. pJiilos. Schrift., 3, 562, 565, 571, 579, 580, Dutens, 2, 
Pt. I., 329, 330; Pt. II., 214, Protogsea, § 17; Systems nouveau, § 6, Ger- 
hardt, 4, 480, Erdmanu, 125, b, Jacques, 1, 471, trans. Duncan, Philos. Wks. of 
Leibnitz, 73; Principes de la Nature et de la Grace, § 6, G., 6, 601, E., 715, b, 
trans. D., 212; G., 7, 568. He puhlished the greater part of his discussions and 
investigations in 112 papers in the Philos. Transactions of the Royal Society, 
and in 26 papers in the Memoirs of the Paris Academy of Sciences, of both 
of which bodies he was a member. The most complete collection of his works 
is the Opera omnia sen arcanse naturse ope micro scopiorum detecta, Leyden, 
1719-22, 4 vols., 4to ; from this, Select Works, trans, by Samuel Hoole, London, 
1800-1807, 2 vols, 4to, does not contain the letter to Wren. There is a Life in 
Dutch by Haaxman, Leyden, 1875. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 347 

mation. ' Perhaps some one will arise who will maintain that, 
although the soul can come only from one sex, both sexes 
furnish something of the organism, and that from the two 
bodies one is made, just as we see that the silk-worm is as it 
were a double animal, and encloses a flying insect under the 
form of the caterpillar : in such darkness are we still upon so 
important a point. Some day perhaps the analogy of plants 
will give us some light, but at present we have but little in- 
formation regarding the generation of plants themselves, the 
surmise concerning the pollen which has been remarked, as 
that which might correspond to the masculine semen, not 
yet being very clear. Besides a slip of a plant is very often 
capable of giving a new and complete plant, to which no 
analogy is as yet seen in animals ; also we cannot say that 
the foot of an animal is an animal, as each branch of the tree 
seems to be a plant capable of fruit-bearing by itself. Fur- 
thermore the intermixture of species, and even the changes 
in one and the same species often go on with much success 
in plants. Perhaps at some time or place in the universe 
the species of animals are, or were, or will be more subject 
to change than they are at present with us, and many animals 
who have somewhat of the cat, as the lion, the tiger, and the 
lynx, might have been of one and the same race and may now 
be as it were new subdivisions of the ancient species of cats. 
Thus I always return to what I have more than once said that 
our determinations of physical species are provisional and 
proportional to our knowledge. 1 

§ 24. Ph. Men at least in making their divisions of species 
have never thought of substantial forms, save those who, in 
this single corner of the world where we are, have learned the 
language of our schools. 

Th. It seems that lately the term substantial forms has 
come into disrepute with certain classes and that they are 
ashamed to speak of them. Meanwhile there is perhaps in 
that circumstance more of fashion than of reason. The scho- 
lastics employed inaptly a general notion, when they used it 
to explain particular phenomena ; but this abuse does not de- 
stroy the thing. The soul of man is a little disconcerting to 

Leibnitz here touches upon the theory of evolution, or development, but 
himself within very moderate limits in the statement of his views. — Tk. 



348 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

the dogmatism of some of our moderns. There are some who 
admit that it is the form of man ; but they also affirm that it 
is the only substantial form of known nature. Descartes thus 
speaks of it, and he censures Regius 1 because he contested this 
quality of a substantial form of the soul and denied that man 
was a unum per se, a being endowed with a veritable unity. 2 
Some think that this excellent man did this as a matter of 
policy. I doubt this a little because I think he had reason 
for so doing. But this privilege is not given to man only, as if 
nature were made of broken sticks. There is room for the 
judgment that there is an infinite number of souls, or, to speak 
more generally, of primitive entelechies, which have something 
analogous to perception and appetite, and which are all, and 
remain always, substantial forms of bodies. It is true that 
species apparently exist which are not truly a unum per se {i.e. 
bodies endowed with a veritable unity, or with an invisible 
essence which makes their entire active principle), any more 
than a mill or watch might be. The salts, the minerals, and 
the metals may be of this nature, i.e. simple contextures or 
masses in which there is a certain regularity. But the bodies 
of both, i.e. animate bodies as well as the contextures without 
life will be specified by their internal structure, since in those 
indeed which are animate, the soul and the machine, 3 each by 



i Pierre Sylvain Regis — Latin, Regius — 1632-1707, a celebrated Cartesian, 
at first destined for the church, but who, on going to Paris to study theology 
at the Sorbonne, heard Rohault (cf. ante, p. 233, note 2) on Cartesianism, 
became a zealous adherent of the doctrine, renounced the priesthood, and gave 
himself up to teaching the new philosophy. His enormous success aroused the 
opposition of Harlay, the Archbishop of Paris, who forbade his teaching. He 
therefore turned to composition, expounding his philosophical ideas "in his 
Cours entier de philosophic, or Systeme general selon les principes de Des- 
cartes, 4 vols., 4to, Paris, 1690, 2d ed., 3 vols., Amsterdam, 1691. He inter- 
preted Descartes in the sense of empiricism, and thus drew upon himself the 
philosopher's censure, cf. Descartes, Remarks on the Programme of Regius, 
Works, ed. Cousin, Paris, 1824-26, Vol. 10, pp. 70-111; see also Veitcb, The 
Method, Meditations and Selections from the Principles of Descartes, 8th ed., 
Edinburgh, 1881, pp. 278, 287. His doctrines were a reaction against the ultra 
idealism of Malebranche. Other works of his are Response a la censura 
philosophise cartesianx, 12rno, Paris, 1691; L' Usage de la Raison et de la Foi, 
4to, Paris, 1704. — Tr. 

2 Cf. Descartes, 1596-1650, Epist., I., 89, pp. 292-293, ed. of 1668, p. 261, ed. 
of 1692, Cousin's ed., Vol. 8, pp. 579-583; Gerhardt, Leibniz, philos. Schrift., 
6, 547, 550 sq.— Tr. 

3 I.e. body, according to the linguistic usage of the Cartesians. — Tr. 



en. vi] ON HUMAN UNDERSTANDING 349 

itself, suffice for the determination ; for they agree perfectly, 
and although having no immediate influence the one upon the 
other, they are mutually expressive, the one having concen- 
trated into a perfect unity all that the other has dispersed in 
the manifold. Thus, when the arrangement of species is the 
question, it is useless to dispute about the substantial forms, 
although it may be well for other reasons to know if there are 
any and what their nature is ; for without this one would be a 
stranger in the intellectual world. For the rest the Greeks 
and the Arabians have spoken of these forms as well as the 
Europeans, and if the common people do not speak of them, 
no more do they speak of algebra or of surds. 1 

§ 25. Ph. Languages were formed before the sciences, and 
ignorant and unlettered people reduced things to certain 
species. 

1 The doctrine of the substantial forms, of which the Mediaeval schoolmen 
made so much use, finds its origin and point of departure in the elSos and ova-Ca 
of Plato and Aristotle. Aristotle used ovtria in two senses ; in its primary and 
proper signification, as a concrete and individual substance, a compound 
(<rvvo\ov) of matter (ii\ v ) and the determining principle, form (elSo?), in which 
sense individual things were called "first substances" (n-pwrai owiai ) ; sec- 
ondly, as applied to the genus, in which sense species were called " second 
substances" (SevVepai ouo-i'ai). According as they were nominalists or realists, 
the Schoolmen, in their interpretation of Aristotle, regarded the substantial 
forms as mere concepts of genus and species, the product of the abstraction- 
power of the mind, which might correspond to, though they did not constitute, 
the reality of things ; or, as real universals existing in concrete things, consti- 
tuting their inmost essence and determining its nature. Locke adopts the 
nominalistic view of these forms as piirely subjective having no corresponding 
reality in nature. Leibnitz maintains them in the realistic sense as expres- 
sions of the reality of the "first substances," and in direct connection with 
them develops his doctrine of monads. Cf. JDiscours de Metaphys., 1686, § 10 
sq., Gerhardt, 4, 443; Systbne nouveau, 1695, §§ 3, 4, 11, G. 4, 478 sq. (also 
ibid, first draft, G. 4, 473), Erdmann, 124, Jacques, 1, 470, trans. Duncan, 
Philos. Whs. of Leibnitz, 72 ; De ipsa natura, 1698, §§ 11, 12, G. 4, 510, E. 157, 
J. 1, 462, D. 120; also G. Hartenstein, Ueber Leibniz's Lehre v. d. Verhaltniss 
d. Monaden z. Eorperwelt, in his Histor. philos. Abhandl., Leipzig, 1870, 469 
sq., Stein, Leibniz u. Spinoza, Berlin, 1890, 158 sq., Dillmann, Eine n. Darstg. 
d. Leibniz. Menadenlehre, Leipzig, 1891, 225 sq. For Leibnitz's theological 
use of Aristotle's forms — dSri — cf. The'odicee, Pt. III., §§ 335-6, and J. H. v. 
Kirchmann's note 246 thereto, Band 80, p. 133, and note 62 f., Bd. 82, p. 87, of 
his Philos. Bibliothek. Leipzig, 1879. On the elSos and ova-U of Plato and Aris- 
totle, cf. Wallace, Outlines of the Philos. of Aristotle, §§ 10, 31, 32, 34, 37, and 
Zeller, Philos. d. Griech., II., 1 [Vol. 3], 658 sq., 4th ed. 1889, II. 2 [Vol. 4] , 304 
sq., 3d ed., 1879. For the Scholastic doctrine, cf. B. Haure'au, Histoire de la 
philos. scholastique, 2d ed., Paris, 1872-80; A. Stockl, Gesch. d. Philos. d. 
Mittelalters, Mainz, 1862-66 ; C. Prantl, Gesch. d. Logik im Abendlande, Leip- 
zig, 1855-1870, passim. Cf. also G. 1, 16, 22 sq., 4, 208. — Te;, 



850 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

Th. True, but persons who study these matters rectify the 
popular notions. Assayers have found exact means of dis- 
cerning and separating the metals ; botanists have enriched 
wonderfully the doctrine of plants, and the experiments made 
upon insects have opened for us a new path in the knowledge 
of animals, but we are still very far distant from the half of 
our course. 

§ 26. Ph. If species were a work of nature they could not 
be conceived so differently by different persons. Man appears 
to one person an animal without feathers, with two feet and 
with large nails, and another after a more profound exami- 
nation adds to these reason. Many people, however, deter- 
mine the species of animals by their external form rather than 
by their birth, since the question has been put more than once 
whether certain human foetuses should be admitted to baptism or 
not, for the sole reason that their external configuration differed 
from the ordinary form of infants, without knowing whether 
they were not as capable of reason as infants cast in another 
mould, some of whom are found, who, although of an approved 
form, are never able to exhibit during their entire life as much 
reason as appears in an ape or elephant, and who never give 
any indication of being governed by a rational soul. Whence 
it appears evident that the external form which alone has 
found mention, and not the faculty of reasoning which no one 
could know would be wanting in its time, has been regarded 
essential to the human species. And in these circumstances 
theologians and jurisconsults the most learned have been 
compelled to renounce their sacred definition of rational 
animal, and to put in its place some other essence of the 
human species. " Mr. Menage," (Menagiana Tom. I. p. 278, 
of the Dutch edition of 1694,) l " furnishes us the example of a 
certain abbot of St. Martin, which deserves to be related. 
When this abbot of St. Martin, he says, came into the world, 
he had so little the figure of a man, that he resembled rather 
a monster. For some time they deliberated whether he 
should be baptized. He was baptized however, and declared a 
man provisionally, i.e. till time should show what he was. He 

1 Menagiana sive excerpta ex ore JEgidii Menagii, 1st ed., 1 vol., 12mo, 
Paris, 1693, 3d ed., enlarged arid corrected by La Monnoye, Paris, 1715. Erd- 
mann, Jacques, and Schaarschmidt in his German trans, erroneously read 1649. 
— Tr. 



ch. vi] ON HUMAN UNDERSTANDING 351 

was so disfigured by nature, that they called him all his life 
the Abbot Malotru. He was of Caen." There was a child 
who came very near being excluded from the human species 
simply because of his shape. He narrowly escaped as it was, 
and it is certain that a figure a little more deformed would 
have deprived him of it for ever and have caused him to 
perish as a being who ought not to pass for a man. Yet no 
reason can be given why a rational soul could not have been 
lodged in him, if the lineaments of his face had been a little 
more altered ; why a visage a little longer, or a flatter nose, or 
a wider mouth could not have subsisted as well as the rest of 
the irregular figure with a soul and with qualities which made 
him capable, wholly disfigured as he was, of being clothed 
with dignity in the church. 

Th. Up to the present time, no rational animal has been 
found with an external figure very different from ours, there- 
fore, when the question arose of baptizing a child, race and 
figure have always been considered only as marks by which to 
judge whether it was a rational animal or not. Thus theo- 
logians and jurisconsults have never needed to renounce for 
that reason their sacred definition. 

§ 27. Ph. But if that monster, of which Licetus, 1 Bk. I., 
chap. 3, speaks, with a man's head and a hog's body, or other 
monsters, with the heads of dogs and of horses, etc., upon the 
bodies of men had lived and could have spoken, the difficulty 
would be much greater. 

1 Fortunio Liceti, 1577-1657, a celebrated Italian physician and scholar, who 
taught logic at Pisa, 1600-1609 ; philosophy at Padua till 1631 ; then philosophy 
at Bologna ; and finally, theoretic medicine at Padua from 1645 till his death. 
He was a great admirer of Aristotle, and wished to admit nothing beyond his 
doctrines, and thus contributed to render both philosophy and medicine sta- 
tionary. For the matter to which Leibnitz here refers, ef. Licetus, De spontaneo 
viventium ortu, lib. quat., fob, Vicentise, 1618, Bk. I., chap. 28, pp. 34-36, Sexta 
coufirmatio spontanei ortus hominum petita ex humanis figuris in belluis, ac 
lapidibus enodatur aperiendo talium figurarum caussas, in which chapter 
Licetus treats of various monsters, referring to his De monstrontm mentioned 
below, and to his father's, Giuseppe Liceti, an Italian physician, died 1599, 
Dialogus de genitalium usu et dignitate, or II Ceva, dell' ouvero eccellenza ed 
uso de' genitali, 1598, De monstrorum caussis, natura, et differentiis lib. duo, 
2d ed., 4to, Petavii, 1634, pp. 13, 183, 194 : " De monstrorum humanorum reale 
existential " ; the same, with additions by Gerard Blasius, 4to, Amstelodami, 
1665, pp. 13, 183, 194 ; the same, in the French trans., Traite' des monsires, by 
Jean Palfyn, 1650-1730, in his Desertion anatomique des parties de lafemme 
qui servent a la generation, etc., 4to, Leyden, 1708, pp. 13, 197, 208. — Tr. 



352 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

Th. I admit it, and if that occurred and if any one had done, 
as a certain writer, a monk of the olden time, named Hans 
Kalb (Jean le veau — John the calf) who 1 painted himself 
with a calf's head, the pen in his hand, in a book he had 
written, which procedure caused some foolishly to think that 
this writer had in reality a calf's head, — if, I say, that hap- 
pened, we should be more cautious hereafter in getting rid of 
monsters. For there is some probability that reason would 
maintain it with theologians and with jurisconsults in spite of 
the figure and even in spite of the differences which the 
anatomy would furnish to the physicians, which would as 
little injure the quality of man as the reversal of the viscera 
in that man whose anatomy some persons of my acquaintance 
have seen at Paris, which has made some stir, in which nature 

" Peu sage et sans derate en debauche 
Placa le foye au coste gauche 
Et de meine vice versa 
Le cceur a la droite placa," 

i.e. "unwise and doubtless in debauch placed the liver upon the 
left side and likewise vice versa the heart upon the right," 
if I rightly remember some of the verses which the late Mr. 
Alliot 2 the father (a famous physician because he passed as 
skilful in the treatment of cancers) showed me of his own 
making upon this prodigy. It is a matter of course, provided 
the variety of conformation does not go too far in the case 
of rational animals and that no return is made to the times 
when animals spoke, for then we should lose our especially 
peculiar advantage of reason 3 and should henceforth be more 
attentive to birth and the external in order to be able to dis- 

1 Erdmann and Jacques add " qui " after " le veau." — Tr. 

2 Pierre Alliot, a French physician of the seventeenth century, horn at 
Bar-le-Dnc, reputed to have great skill in the treatment of cancer and other 
malignant ulcers. His most distinguished patient was Anne of Austria, the 
mother of Louis XIV., whom he treated unsuccessfully in Paris in 1665. Not- 
withstanding his failure, he was appointed physician to the king. His published 
works include Theses medicse de motu sanguinis circulate) et de morbis ex sere, 
Pont-a-Mousson, 1663, 8vo ; Epistola de cancro apparente, and Nuntius profii- 
gati sine ferro et igne carcinomatis, both Bar-le-Duc, 1664, 12mo. His son, 
Jean Baptiste Alliot, was physician to Louis XIV., and published Traite du 
cancer oil Von explique sa nature et on Von propose les moyens les plus surs 
pour le guerir methodiquement, Paris, 1698, 12mo. — Tr. 

3 The French text is: " nostre privilege de la raison en preciput," etc. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 353 

cern those of Adam's race from those who may descend from 
a king or patriarch of some canton of apes in Africa ; and our 
learned author was right in his remark (§ 29) that if Balaam's 
ass had all her life discoursed as rationally as she did once 
with her master (supposing it was a prophetic vision), she 
would always have had difficulty in obtaining rank and a seat 
among women. 

Ph. You laugh, I see, and perhaps the author laughed also ; 
but, to speak seriously, you see that you cannot always assign 
fixed limits to species. 

Th. I have already agreed to this ; for when the question 
concerns fictions and the possibility of things, the passage 
from species to species may be insensible, and to discern them 
would sometimes be about as impossible as to decide how 
much hair a man must be allowed that he may not be bald. 
This indeterniinateness would be true even when we knew 
perfectly the internal nature of the creatures under discussion. 
But I do not see that it can prevent things from having real 
essences independent of the understanding, and us from know- 
ing them. It is true that the names and limits of species 
would sometimes be like the names of measures and weights, 
where choice is necessary in order to have fixed limits. But 
ordinarily there is nothing of the kind to fear, species too 
much alike seldom occurring together. 

§ 28. Ph. It seems we agree here at bottom, although we 
differ somewhat in terms. I also admit that there is less 
arbitrariness in the denomination of substances than in the 
names of the mixed modes. For few venture to unite the 
bleating of a sheep with the figure of a horse, or the color of 
lead with the weight and fixedness of gold, and we prefer to 
draw copies after nature. 1 

Th. This is not so much because in substances regard is 
had only to that which exists effectively, as because there is no 
certainty in the case of physical ideas (which are not very 
thoroughly understood) that their union is possible and useful, 
if there is no actual existence to guarantee it. But this also 
takes place in the modes, not only when their obscurity is 
impenetrable by us, as sometimes happens in physics, but also 

1 That is, to follow experience in the formation of our ideas, and to conform 
our inner world iu general to that furnished by nature. — Te. 

2a 



354 LEIBNITZ'S CEITIQUE OF LOCKE [mc. in 

when it is difficult of penetration, enough examples of which 
occur in geometry. For in both of these sciences it is not 
within our power to make combinations according to our fancy, 
otherwise we should be right in speaking of regular decahedrons, 
and should seek in the semicircle 1 a centre of magnitude, as 
there is in it a centre of gravity. For it is in fact surprising 
that the first is there, and that the second cannot be. Now 
while in the modes the combinations are not always arbitrary, 
we find on the other hand that in substances they sometimes 
are so ; and it often depends on ourselves to make combina- 
tions of qualities in order further to define substantial beings 
in advance of experience, when we understand enough of these 
qualities to judge of the possibility of the combination. Thus 
it is that expert gardeners in the orangery can rationally and 
successfully propose to produce some new species and give it 
a name in advance. 

§ 29. Ph. You will always agree with me that when the 
question arises of defining species, the number of ideas com- 
bined depends upon the different application, industry, or fancy 
of the one forming this combination, as it is the figure which 
regulates most frequently the determination of the species of 
vegetables or animals, and likewise as regards the majority of 
natural bodies which are not produced by seeds, it is the color 
which is most strongly adhered to. § 30. In truth these are 
often only confused conceptions, gross and inexact, and it is 
very essential that men agree as to the precise number of 
simple ideas or qualities which belong to a given species or a 
given name, for pains, skill, and time are needed to find simple 
ideas which are constantly united. However a few of the 
qualities composing these inexact definitions are ordinarily 
sufficient in conversation ; but in spite of the stir about gen- 
era and species, the forms, of which so much has been said in 
the schools, are only chimeras which avail us nothing in fur- 
nishing an entrance into the knowledge of specific natures. 

Th. Whoever makes a possible combination, is not at all 
mistaken therein, nor in giving it a name ; but he is mistaken 

1 Such combinations of essentially self-contradictory ideas may easily be 
united in a complex term, and be apparently clear and possible, until analyzed 
and compared with reality, when their confusion and impossibility is at once 
made evident. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 355 

if he thinks that his conception is altogether that which others 
more expert have conceived under the same name or in the 
same body. He perhaps conceives a genus too common instead 
of another more specific. There is nothing in all this contrary 
to the schools, and I do not see why you return here to the 
charge against genera, species, and forms, since it is necessary 
for you to recognize indeed the genera, species, and even the 
internal essences or forms, which we do not pretend to employ 
in order to know the specific nature of the thing, although we 
admit we are still ignorant of them. 

§ 30. Ph. It is at least evident that the limits we assign to 
species are not exactly conformed to those established by nature. 
For in our need of general names for present use, we do not 
put ourselves to the trouble of discovering the qualities which 
would give us superior knowledge of their most essential dif- 
ferences and agreements, but we ourselves distinguish them 
into species in virtue of certain appearances which are mani- 
fest to everybody, that we may more easily communicate with 
others. 

Th. If we combine compatible ideas, the limits we assign to 
species are always exactly conformed to nature ; and if we are 
careful to combine ideas actually found together, our notions 
are also conformed to experience ; and if we consider them 
as provisional only for actual bodies, without excluding ex- 
periment made or to be made for further discovery therein, 
and if we have recourse to experts, when a definite question 
arises with reference to what is openly understood by the 
name, we shall not err in the matter. Thus nature may 
furnish ideas the most perfect and most convenient, but she 
will not give the lie to those we have which are good and 
natural, although not perhaps the best and most natural. 

§ 32. Ph. Our generic ideas of substances, as that of metal, 
for example, do not follow exactly the models set them by 
nature, since you cannot find any body including simply malle- 
ability and fusibility without other qualities. 

Th. No one asks for such models and it would not be reason- 
able to ask for them ; furthermore they do not occur in the 
most distinct notions. We never find a number in which there 
is nothing to notice but multitude in general, an extension in 
which there is only extension, a body in which there is only 



356 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

solidity, and no other qualities ; and when the specific differ- 
ences are positive and contrary it is very essential that the 
genus share in them. 

Ph. If, then, any one thinks that a man, a horse, an animal, 
a plant, etc., are distinguished by real essences made by nature, 
he must think that nature is very liberal with these real essences, 
if she produces one of them for the body, another for the 
animal, and still another for the horse, and that she bestows 
freely all these essences upon Bucephalus ; whilst genera and 
species are only signs more or less comprehensive. 

Th. If you take real essences as these substantial models, 
which exist as a body and nothing more, an animal and nothing 
more specific, a horse without individual qualities, you are 
right in treating them as chimeras. And no one has main- 
tained, I think, not even the greatest Realists of former times, 
that there are as many substances confining themselves to the 
generic as there are genera. But it does not follow that if 
general essences are not this, they are merely signs ; for I have 
many times remarked to you that there are possibilities in the 
resemblances. In like manner from the fact that colors are not 
always substances or extracted dyes, it does not follow that 
they are imaginary. For the rest you cannot think nature too 
liberal; she is so beyond all that we can invent, and all advan- 
tageous compatible possibilities are found realized upon the 
grand theatre of her representations. There were formerly 
two axioms among philosophers : that of the Realists seemed 
to make nature prodigal, and that of the Nominalists seemed 
to declare her stingy. The one says that nature suffers no 
vacuum, and the other that she does nothing in vain. These 
two axioms are good provided you understand them ; for nature 
is like a good economist, who saves where it is necessary in 
order to be grand at times and places. She is grand in effects, 
and sparing in the causes she employs. 

§ 34. Ph. Without amusing ourselves longer with this dis- 
cussion upon real essences, it is enough that we obtain the pur- 
pose of language and the usage of words which is to indicate 
our thoughts in an abridged form. If I wish to speak to any 
one of a species of birds three or four feet in height, whose 
skin is covered with something between feathers and hair, of a 
dark brown color, without wings, but in their place two or 



en. vi] ON HUMAN UNDERSTANDING 357 

three small branches, like those of the broom, which descend 
to the lower part of the body, with long and large legs, the 
feet armed only with three claws and without a tail ; I am 
compelled to make this description whereby I can make myself 
understood by others. But when I am told that the name of 
this animal is Cassowary, I can then use this name to designate 
in discourse this entire complex idea. 

Th. Perhaps a very exact idea of the covering of the skin 
or of some other part would suffice by itself alone to distin- 
guish this animal from every other known, as Hercules was 
known by his gait, and as the lion was recognized by his claw 
according to the Latin proverb. But the more circumstances 
you heap up, the less provisional is your definition. 

§ 35. Ph. We may curtail the idea in this case without 
prejudice to the thing; but when nature curtails it, it is a 
question whether the species remains. For example : if a 
body existed having all the qualities of gold except mallea- 
bility, would it be gold ? it depends upon men to decide. 
They are then the ones who determine the species of things. 

Th. Not at all ; they would determine only the name. But 
this experience would teach us that malleability has no neces- 
sary connection with the other qualities of gold taken together. 
It would teach us then a new possibility and consequently a 
new species. As for gold which is eager x or brittle, this comes 
only from additions, and is not consistent with the other tests 
of gold; for the cupel and antimony remove this eagerness 
from it. 

§ 36. Ph. A portion of our doctrine follows that will appear 
very strange. Each abstract idea having a certain name forms 
a distinct species. But what of that, if nature so wills it ? I 
should be glad to know why a lap-dog and a greyhound are not 
as distinct species as a spaniel and an elephant. 

Th. I have distinguished above the different senses of the 
word species. Taking it logically, or mathematically rather, 
the least dissimilitude may suffice. Thus each different idea 
will give another species, and it makes no difference whether 
it has a name or not. But, physically speaking, we do not at- 
tend to all the varieties, and we speak either distinctly when the 
question concerns only appearances, or conjecturally when the 
i Of. Locke, Philos. Works, Vol. 2, p. 65 (Bohn's ed.). — Tr. 



358 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

question concerns the inner truth of things, presuming therein 
some essential and immutable nature, like reason in man. 
_We presume then, that whatever differs only by accidental 
changes, like water and ice, quicksilver in the liquid form and 
as sublimate, is of the same species : and in organic bodies the 
provisional mark of the same species is usually placed in the 
generation or race, as in those most alike it is placed in repro- 
duction. It is true we cannot judge with precision, for lack 
of knowledge of the inner nature of things ; but, as I have 
said more than once, we judge provisionally and often con- 
jecturally. But when we wish to speak only from the external, 
for fear of saying nothing certain, there is some latitude ; and 
to dispute then whether a difference is specific or not is to 
dispute about the name ; and in this sense there is so great a 
difference between dogs, that we may very well say that the 
house-dogs of England and the dogs of Boulogne belong to 
different species. It is not impossible, however, that they 
belong to a remote identical or similar race, which we should 
find if we could go back very far, and that their ancestors 
were alike or identical, but that after great changes, some of 
the posterity have become very large and others very small. 
We may indeed believe also without offending reason that 
they have in common an inner nature, constant, specific, which 
is no longer subdivided thus, or which is not found here in 
several other such natures, and consequently is no longer 
varied save by accidents ; although there is also nothing to make 
us judge that this must necessarily be so in all that which we 
call the lowest species (species infima). But there is no likeli- 
hood that a spaniel and an elephant are of the same race, and 
that they have such a specific common nature. Thus in the 
different sorts of dogs, speaking of appearances, we may dis- 
tinguish species, and speaking of the inner essence we may be in 
suspense : but comparing the dog and the elephant there is no 
reason for attributing to them externally or internally that 
which would make us think them of one and the same species. 
So there is in this case no occasion for suspense in the face of 
the presumption. In man we can also distinguish species 
logically speaking, and if we stopped with the external we 
should find also, speaking physically, differences which could 
pass as specific. Thus a traveller was found who thought 



tea. vi] ON HUMAN UNDERSTANDING 359 

that the Negroes, Chinese, and finally the Americans were not 
of one and. the same race among themselves nor with the 
peoples resembling us. But as we know the essential inner 
nature of man, i.e. the reason, which dwells in the man him- 
self and is found in all men, and as we notice nothing fixed 
and internal among us which forms a subdivision, we have no 
reason to judge that there is in men, according to the truth of 
the inner nature, an essential specific difference, while such 
difference is found between man and beast, supposing that the 
beasts are only empirical, according as I have explained above, 
as in fact experience gives us no reason for forming any other 
judgment. 

§ 39. Ph. Let us take the example of an artificial thing 
whose internal structure is known to us. A time-piece that 
only indicates the hours, and one that strikes, are of one 
species only for those who have only one name by which to 
designate them ; but for him who designates the first by the 
name watch, and second clock, they are in relation to him dif- 
ferent species. It is the name and not the inner disposition 
which makes a new species, otherwise there would be too 
many species. There are watches with four wheels, and 
others with five ; some have strings and fusees, 1 and some not ; 
some have a free balance, and others are regulated by a spiral 
spring and others by hog's bristles. Does any one of these 
things suffice to make a specific difference ? I say no, so 
long as these time-pieces agree in name. 

Th. And I for my part say yes, for without stopping at 
names, I should consider the varieties of contrivance and 
especially the differences of the balance ; for since a spring 
has been applied which governs the vibrations according to 
its own and consequently renders them more equal, pocket- 
watches have changed their character, and have become in- 
comparably more accurate. I have indeed mentioned before 
another principle of equality which might be applied to 
watches. 

Ph. If any one wishes to make divisions based upon the 
differences which he knows in the internal configuration he 
may do so ; but they would not be distinct species with rela- 
tion to the people who are ignorant of this construction. 

1 Locke has "physies," Philos. Works, Vol. 2, p. 67 (Bohn's ed.). — Tr. 



300 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

Th. I do not know why those with yon always wish to 
make virtues, truths, and species depend upon our opinion or 
knowledge. They exist in nature, whether we know it and 
approve or not. To speak otherwise is to change the names 
of things and received language without any reason. Men up 
to the present time have believed that there are many kinds 
of clocks or watches, without informing themselves in what 
they consist or how they may name them. 

Ph. You have however recognized not long since that when 
men wish to distinguish physical species by appearances, they 
limit them in an arbitrary way, where they find it to the pur- 
pose, i.e. according as they find the difference more or less 
considerable and according to the end they have. And you 
yourself have made use of the comparison of weights and 
measures, which are regulated and given their names accord- 
ing to the good pleasure of man. 

Th. It is since then that I have begun to understand you. 
Between specific differences purely logical, for which the least 
variation of assignable definition suffices, however accidental 
it be, and between specific differences purely physical, based 
upon the essential or immutable, we may place a mean, which 
cannot be precisely determined ; it is regulated by the most 
important appearances, which are not altogether immutable, 
but which do not change easily, the one approaching the 
essential more than the other. And as a connoisseur too may 
go farther than another, the thing appears arbitrary and has 
some relation to men, and it appears convenient to regulate 
names also according to these principal differences. We can 
then speak thus, that there are specific civil differences and 
nominal species which must not be confounded with what I 
have called above nominal definitions, and which have place 
in differences specifically logical as well as physical. For the 
rest, besides common usage, the laws themselves may give 
authority to the significations of words, and then the species 
would become legal, as in the contracts which are called 
nominati, i.e., designated by a particular name. For example 
as the Roman Law made the age of puberty commence at the 
end of the fourteenth year. This entire consideration is not 
to be despised, but I do not see that it is of very much use 
here, for besides the fact that you have appeared to me to 



en. vi] ON HUMAN UNDERSTANDING 361 

apply it sometimes where it did not apply, we shall accom- 
plish nearly the same result if we consider that it rests with 
men to proceed in subdivisions as far as they find them to 
the purpose, and to abstract ulterior differences without the 
necessity of denying them ; and that it also rests with them 
to choose the certain, notwithstanding the uncertain, in order 
to fix some notions and measures by giving them names. 

Ph. I am much pleased that we are here no longer so far 
apart as we appeared. § 41. You agree then, sir, I see, that 
artificial as well as natural things are species contrary to the 
view of some philosophers. § 42. But before leaving the 
names of substances, I would add that of all the diverse ideas 
we have, they alone are ideas of substances which have proper 
or individual names ; for it rarely happens that men need to 
make frequent mention of any individual quality or other 
individual accident. Besides individual acts perish at once 
and the combination of circumstances which thereby comes 
about only subsists as in the substances. 

Th. There are, however, cases where it has been necessary 
to remember an individual accident and to give it a name ; 
thus your rule is ordinarily good, but there are exceptions to 
it. Religion furnishes us with them ; for example we cele- 
brate each year the memory of the birth of Jesus Christ. The 
Greeks call this event Theogeny, and that of the adoration of 
the Magi, Epiphany. And the Hebrews call the Passali par 
excellence the passage of the angel who caused the death of 
the eldest sons of the Egyptians without touching those of the 
Hebrews ; and this is why they were to celebrate its memory 
every year. As for the species of artificial things, the scholastic 
philosophers found difficulty in admitting them into their pre- 
dicaments ; but there was little necessity for their hesitation 
since these predicamental tables were destined for use in mak- 
ing a general review of our ideas. It is well however to rec- 
ognize the difference existing between perfect substances and 
between the assemblages of substances (aggregata) which are 
substantial entities composed either by nature or by the art of 
man. Eor nature has also such aggregates, as the bodies whose 
mixture is imperfect (imperfecte mixta) to use the language of 
our philosophers, which constitute no unum, per se and do not 
possess in themselves a perfect unity. I believe however that 



362 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

the four bodies which they call elements, and think simple, and 
the salts, metals, and other bodies which they think are per- 
fectly mixed, and to which they attribute their temperaments, 1 
are not unum per se either; so much the more as we must 
judge that they are uniform and homogeneous only in appear- 
ance, and even a homogeneous body would not cease to be a 
mass. In a word, the perfect unity must be reserved to bodies 
animated, or endowed with primitive entelechies; for these 
entelechies are analogous to souls and are as individual and 
imperishable as they ; and I have elsewhere affirmed that their 
organic bodies are practically machines, but which surpass the 
artificial machines of our invention as much as the inventor of 
the natural machines surpasses us. For these natural machines 
are as imperishable as the souls themselves, and the animal 
with the soul subsists always : it is (the better to explain my- 
self by something pleasing, wholly laughable as it is,) as if a 
harlequin wished to strip himself in the theatre, but could not 
succeed because he had an indefinite number of garments one 
upon another ; although these infinite replications of organic 
bodies, which exist in an animal, are not so similar nor so 
applied the one to the other, as the garments, nature's art 
being of a wholly different subtility. All this shows that the 
philosophers have not been wholly in the wrong in putting so 
great distance between artificial things and between natural 
bodies endowed with a real unity. But it belonged only to 
our time to develop this mystery and make understood its 
importance and consequences in order thoroughly to establish 
natural theology and what is called Pneumatics, 2 in a manner 

1 Leibnitz here alludes to the four elements of Empedocles, c. 492-c. 432, 
b. c, viz., fire, air, earth, water, adopted by Plato and Aristotle and called by 
the Peripatetics warmth, cold, dryness, humidity, a mixture of which in vary- 
ing proportions constituted all bodies. Cf. Zeller, Philos. d. Griec, I. 2 [Vol. - 
2], 758 sq., 5th ed., 1892, II. 1 [Vol. 3], 796 sq., 4th ed., 1889, II, 2 [Vol. 4], 431, 
sq., 832 sq., 3d ed., 1879. The state of a body resulting from the proportional 
disposition of these primary constituent elements or qualities was called its 
temperament, the character of the temperament varying according to the pre- 
dominance of one or more of the elements. The scholastics discussed the 
question whether the temperament comprised these four primary qualities, or 
whether it did not consist in a fifth simple quality, the outcome of the recipro- 
cal action of the four primary qualities, which resulted in their entire destruc- 
tion. Cf. also Gei-ha,vdt, Leibniz, philos. Schrift., 4, 207. — Tr. 

2 Cf. ante, p. 50, note 2. Schaarschmidt states that Pneumatics — Pneumatik 
— with the meaning — Doctrine of the Spirit, Lehre vom Geiste — Psychology 



en. vi] ON HUMAN UNDERSTANDING 363 

truly natural and in agreement with our experiments and 
understanding, and requiring the loss of none of the important 
considerations they are destined to furnish, or rather enhanc- 
ing their value, as does the system of pre-established harmony. 1 
And I believe that we can best conclude this long discussion 
of the names of substances only by that means. 

— occurs in Alsted's Encyclopsedie, Herborniae, 1630, cf. ante, p. 311, note 2, and 
that Stephen Chauvin in his Lexicon philosophicum, Leovardise, 1713, adopted 
it and explained it by Pneumatology and Fneumatosophy. The term is now 
confined to physical science, and denotes that department of hydrodynamics 
which treats of the properties of gases as distinguished from liquids. Cf. 
Krauth-Flemming, Vocab. of the Philos. Sciences, p. 388, New York, Sheldon 
& Co., 1883.— Tr. 

1 Cf. New Essays, Bk. IV., chap. 10, §§ 7 and 9, infra, pp.505, 507 ; Systeme 
nouveau, §§ 14-16, Gerhardt, 4, 484-86, Erdmann, 127, a-128, Jacques, 1, 475-77, ' 
trans. Duncan, Philos. Wks. of Leibnitz, 77-79; Considerations sur les principes 
de vie, etc., G. 6, 541, E. 430, trans. D. 165; Principes de la nature et de la 
grace, §§ 7-13, G. 6, 602-604, E. 716, trans. D. 212-215 ; Animadversiones in 
partem generalem Principiorum Cartesianorum, Pt. I. ad Art. 14, G. 4, 358, 
trans. D. 50; Leibniz gegen Descartes und den Cartesianisinus, G. 4, 292-294, 
401-403, 405-406, E. 176, trans. D. 132-138, and his note 49, p. 382 ; Med. de Cog. 
Ver. et Ideis, G. 4, 424, E. 80, a, trans. D. 30. According to Leibnitz, his 
doctrine of monads requires as its necessary complement the existence of God, 
since the single monads, expressing in their own experience all that is beyond 
them, yet without influence on other monads, cannot furnish a sufficient 
ground or reason for the harmony and connection of things in a universal 
world-order. This harmonious world-order existing, its sufficient ground or 
reason must be found in the absolute being, God, who has given to each 
monad the nature which makes it capable of developing itself in its extreme 
individuality in accord and correspondence with every other. The pre-estab- 
lished harmony is thus an actual proof, in accord with experience, of the 
existence of God, and the suggestion of reason in the ontological argument as 
improved by Leibnitz, is confirmed by the comparative and comprehensive 
study of the phenomena of nature. For expositions and criticisms of Leibnitz's 
doctrine, cf. Dewey, Leibniz's Neio Essays, chaps. 11, 12; E. Zeller, Gesch. d. 
deutschen Philos. seit Leibniz, 2d ed., Miinchen, 1875, pp. 88-98, 124-127; F. A. 
Lange, Gesch. d. Mater ialismus, 3d ed., Leipzig u. Gerlohn, 1875 sq., Bk. I., 
Sect. IV., chap. 4, Eng. trans, by E. C. Thomas, 3 vols., Boston, Vol. 2, pp. 
124 sq. ; Kuno Fischer, Gesch. d. n. Philos., Bd. II., Leibniz, 3d ed., Heidelberg, 
1889, pp. 455 sq., 539 sq. — Tr. 



364 LEIBNITZ'S CRITIQUE OE LOCKE [bk. hi 



-CHAPTER VII 

OF PARTICLES 

§ 1. Ph. Besides the words which are used to name ideas, we 
need those which signify the connection of ideas or proposi- 
tions. This is, this is not, are general signs of affirmation or 
negation. But besides the parts of propositions the mind also 
binds together sentences and entire propositions, § 2. availing 
itself of words expressing this union of different affirmations 
and negations and which are called particles; in whose proper 
use the art of speaking well principally consists. It is in 
order that reasoning be consecutive and methodical that terms 
showing the connection, restriction, distinction, opposition, em- 
phasis, etc., are needed. And when they are despised the 
hearer is embarrassed. 

Th. I admit that particles are very useful ; but I am not 
aware that the art of speaking well consists principally in 
their proper use. If any one presents only aphorisms or 
detached theses, as they often do in the universities, or as in 
the case of that which they call among the jurisconsults an 
articulate libel, or as in the articles which are offered to the 
witnesses, then provided we arrange these propositions well 
we shall accomplish, very nearly the same result in making 
them understood as if we had put in the connective and the 
particles ; for the reader supplies them. But I admit there 
would be trouble if you put in the particles badly, and much 
more than if you omitted them. Particles seem to me also 
to unite not only the parts of discourse composed of proposi- 
tions and the parts of the proposition composed of ideas, but 
also the parts of the idea, composed in many ways by the 
combination of other ideas. And it is this last connection 
which is indicated by the prepositions, while the adverbs 
modify the affirmation or negation in the verb ; and the con- 
junctions modify the connection of different affirmations or 
negations. But I doubt not that you have noticed all this 
yourself, although your words seem to state otherwise. 

§ 3. Ph. The part of grammar which treats of particles has 



en. vn] ON HUMAN UNDERSTANDING 365 

been cultivated less than that which represents in order the 
cases, genders, modes, tenses, gerundives, and supines. It is true 
that in some languages they have also arranged the particles 
under some titles by distinct subdivisions with great appear- 
ance of exactness. But it is not sufficient to run through 
these catalogues. One must reflect upon his own thoughts in 
order to observe the forms which the mind takes in discours- 
ing, for the particles are so many indications of the action of 
the mind. 

Th. It is very true that the doctrine of the particles is 
important, and I wish we might enter into much greater 
detail thereupon. For nothing would be more suited to make 
known the different forms of the understanding. Genders are 
of no account in philosophical grammar, but the cases corre- 
spond to the prepositions, and often the preposition is enveloped 
in the noun and as it were absorbed, and other particles are 
concealed in the inflections of the verbs. 

§ 4. Ph. In order properly to explain particles it is not 
sufficient to render them (as is usual in a dictionary) by the 
words of another language which approach most nearly their 
meaning, because it is as difficult to comprehend their precise 
meaning in one language as in another ; besides the significa- 
tions of related words in two languages are not always exactly 
the same and indeed they vary in one and the same language. 
I remember that in the Hebrew language there is one particle 
of a single letter 1 of which there are reckoned up more than 
fifty significations. 

Th. Scholars have attempted to make special treatises upon 
the particles of the Latin, Greek, and Hebrew ; and Strauchius, 2 
a celebrated jurisconsult, has published a book upon the use 
of particles in jurisprudence, where their signification is of no 
small consequence. We ordinarily find, however, that it is 
rather by means of examples and synonymes that they attempt 
to explain them, than by distinct notions. Further we can 

1 I.e. the adverb b- — Tk. 

2 Johann Strauch, 1612-1680, the maternal uncle of Leibnitz, a distinguished 
jurisconsult, Professor at Leipzig-, Jena, and Giessen, and Syndicus in Braun- 
schweig; cf. Guhrauer, G. W. Freiherr v. Leibnitz, Pt. I., Bk. I., pp. 6, 35 sq., 
and Anmerkungen z. erst. Buche, pp. 6, 7. The book here referred to by 
Leibnitz is entitled : Lexicon particularum juris s. de usu et efficaeia quor- 
undam syncategorematum et particularum indeclinab ilium. — Tr. 



366 LEIBNITZ'S CRITIQUE OF LOCKE [ok. m 

not always find a general or formal signification for them, as 
the late Bohlius x called it, which can satisfy all the examples ; 
but notwithstanding this we can always reduce all the uses of 
a word to a definite number of significations. And this is 
what should be done. 

§ 5. Ph. In fact the number of significations greatly exceeds 
that of the particles. In English the particle but has very differ- 
ent significations: (1) when I say: but to say no more, (mais 
pour ne rien dire de plus) as if this particle indicated that the 
mind stops in its course before it has reached the end. But 
saying : (2) I saw but two planets (je vis settlement deux planetes), 
the mind restricts the sense of what it means to that which 
has been expressed by the exclusion of everything else. And 
when I say (3) : you pray, but it is not that God would bring you 
to the true religion, but that he would confirm you in your own 
(vous priez Dieu mais ce n'est pas qu'il venille vous amener a 
la connaissance de la vraye Religion, mais qu'il vons confirme 
dans la vostre), the first but (or mais) designates a supposition 
in the mind which is otherwise than it should be, and the 
second shows that the mind puts a direct opposition between 
what precedes and what follows. (4) All animals have sense, 
but a dog is an animal (tous les animaux ont du sentiment, 
mais le chien est un animal). Here the particle signifies the 
connection of the second proposition with the first. 

Th. The French mais (but) may be substituted in all these 
instances except the second ; but the German allein, taken as 
a particle, which signifies a kind of mixture of mais (but) and 
seulement (only), may doubtless be substituted instead of but 
in all these examples except the last, where its use may be a 
little doubtful. Mais (but) is also rendered in German some- 
times by aber, sometimes by sondern, which indicates a sepa- 
ration or segregation and approaches the particle allein. For 
a proper explanation of the particles, it is not sufficient to 
make an abstract explication as we have just made here ; but 
we must proceed to a paraphrase which may be substituted in 

1 .Samuel Bohl, 1611-1689, Professor at Bostock, who devoted himself to the 
furtherance of the study of Hehrew in Germany, aud whom Leibnitz mentions 
because of his works on the doctrine of the Hebrew Vowel- and Accent-Signs ; 
cf. Dutens, Leibniz, op. om., 5, 190. He published a large number of works, 
among which were Scrntin. S. s. ex accentibus, 1636, and Dissertat. pro for- 
mali Signif. S. S. eruenda, Bostock, 1637. — Tr. 




ch. vii] ON HUMAN UNDERSTANDING 367 

its place, as the definition may be put in the place of the thing 
defined. When we have striven to seek and to determine 
these suitable paraphrases, in all the particles so far as they 
are susceptible of them, we shall have regulated their sig- 
nifications. Let us try to attain this result in our four ex- 
amples. In the first we mean : Thus far only speak we of 
this, and no farther (non piu) ; in the second : I see only two 
planets, and no more ; in the third : You pray God, and for 
this only, viz. to be confirmed in your religion, and no more, 
etc. ; in the fourth, it is as if we said : all animals have sense ; 
it is sufficient to consider that only, and no more is needed. 
The dog is an animal, he then has sense. Thus all these 
examples indicate limits, and a non plus ultra, whether in 
things, or in discourse. Thus but is an end, a limit of the 
course, as if we said : stop, we are there, we have reached our 
But. But, Bute, is an old Teutonic word, signifying some- 
thing fixed, an abode. Beuten (an obsolete word found still in 
some church songs) is to abide. Mais originates from magis, 
as if any one wished to say : as for the surplus ive must leave it, 
which is the same as saying : No more is needed, it is enough, 
let us come to something else, or this is something else. But 
as the use of languages varies in a strange manner, it would be 
necessary to enter much farther into the detail of examples in 
order sufficiently to regulate the significations of particles. In 
French we avoid the double mais by a cependant (however), and 
Ave should say: Vous priez, cependant ce n'est pas pour obtenir 
la verite, mais pour estre confirme dans vostre opinion (You 
pray, not however {cependant) to obtain the truth but (mais) 
to be confirmed in your opinion). The sed of the Latins was 
often expressed formerly by ains, which is the ami of the 
Italians, and the French in modifying it have deprived their 
language of an advantageous expression. For example : There 
was no certainty about it, yet (cependant) we were persuaded 
of what I have informed you, because we like to believe 
what we wish ; but it has been found that it was not so ; but 
(ains) rather, etc. (II n'y avoit rien de seur, cependant on estoit 
persuade de ce que je vous ay mande, parce qu'on aime a croire 
ce qu'on souhaite ; mais il s'est trouve que ce n'estoit pas ' 
cela; ains plustost, etc.). 

§ 6. Ph. My purpose has been to touch this matter only 



368 LEIBNITZ'S CRITIQUE OE LOCKE [bk. hi 

very slightly. I would add that particles often include either 
constantly or in certain constructions the sense of an entire 
proposition. 

Th. But when it is a complete sentiment, I think that it is 
only by means of a kind of ellipsis ; otherwise it is the inter- 
jections alone which in my opinion can subsist by themselves 
and say all in a word, as ah! (hoi me!). For when we say 
mais, adding nothing more, it is an ellipsis for : but let us wait 
for the confirmation of intelligence and not flatter ourselves 
unduly. There is something approximating to this in the nisi 
of the Latins : si nisi non esset, if there were not but (mais). 
For the rest I should not be displeased, sir, had you entered a 
little farther into the detail of the turns of the mind which 
appear marvellous in the use of the particles. But since Ave 
have reason for hastening to conclude this investigation of 
words and to return to things, I do not wish to delay you 
longer, although I truly think that languages are the best 
mirrors of the human mind, and that an exact analysis of the 
signification of words would show us better than anything else 
the workings of the understanding. 



CHAPTER VIII 

OF ABSTRACT AND CONCRETE TERMS 

§ 1. Ph. It is further to be remarked that terms are 
abstract or concrete. Each abstract idea is distinct, so that of 
two the one can never be the other. The mind must perceive 
by its intuitive knowledge the difference between them, and 
consequently two of these ideas can never be affirmed one of 
another. Every one sees at once the falsehood of these propo- 
sitions : humanity is animality or rationality : this is as evident 
as any of the generally received maxims. 

Tli. There is still something to be said thereupon. We 
admit that justice is a virtue, a habit (habitus), a quality, an 
accident, etc. Thus two abstract terms may be stated one of 
another. I am furthermore wont to distinguish two kinds of 
abstracts. There are abstract logical terms, and there are 
also abstract real terms. The abstract real terms, or conceived 



ch. ix] ON HUMAN UNDERSTANDING 369 

at least as real, are either essences or parts of the essence, or 
accidents, i.e. beings added to substance. The abstract logical 
terms are the predications reduced to terms, as if I said : to be 
a man, to be an animal; and in this sense the one can be 
stated of the other, by saying : to be a man is to be an animal. 
But in the realities this has no place. For we cannot say that 
humanity or man-ness 1 {Vhommeite) — (if you please), which is 
the essence of the whole man, is animality, which is only a 
part of this essence ; yet these abstract and incomplete beings 
signified by the abstract real terms have also their genera and 
species which are not less expressed by the abstract real terms : 
thus there is predication between them, as I have shown by 
the example of justice and virtue. 

§ 2. Ph. One may always say that substances have only 
few abstract names ; they have scarcely spoken in the schools 
of humanity, animality, corporality ; and they have never been 
authorized in the world. 

TJi. The reason is that but few of these terms were necessary 
to serve as examples and to throw light upon the general no- 
tion, which was the reason why they were not wholly neglected. 
If the ancients did not use the word humanity in the sense of 
the schools, they said human nature, which is the same thing. 
It is certain also that they said divinity, or rather divine 
nature ; and theologians having found it needful to speak of 
these two natures and of real accidents, they were attached to 
these abstract entities in the schools of philosophy and the- 
ology, and perhaps to a greater extent than was proper. 



CHAPTER IX 

OF THE IMPERFECTIONS OF WORDS 

§ 1. Ph. We have already spoken of the double use of words. 
The one is to register our own thoughts in order to aid our 
memory which makes us talk to ourselves ; the other is to 
communicate our thoughts to others by means of speech. 

1 1 have taken the liberty to coin the word as an equivalent of the French, 
which I think is also coined by Leibnitz to express the abstraction of the 
scholastics. — Tr. 

2b 



370 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

These two uses show the perfection or imperfection of words. 
§ 2. When we speak only to ourselves, it is a matter of indif- 
ference what words we employ, provided we remember their 
meaning and do not change it. But § 3. the use of communication 
is also of two kinds, civil and philosophic. The civil consists 
in the conversation and use of the civil life. The philosophic 
use is that made of words for the purpose of giving precise 
notions and to express in general propositions certain truths. 

Th. Very good : words are not less marks (notce) for us 
(as the characters of arithmetic or algebra may be) than signs 
for others ; and the use of words as of signs is as much in 
place when the question concerns the application of general 
precepts to the usage of life, as when it concerns the discovery 
or verification of these precepts. The first use of signs is civil, 
and the second philosophic. 

§ 5. Ph. Now it is difficult, chiefly in the following cases, 
to learn and retain the idea which each word signifies, (1) 
when these ideas are very complex; (2) when the ideas com- 
posing a new one have no natural bond between them, so that 
there is in nature no fixed measure nor any model to rectify and 
regulate them ; (3) when the model is not easy to be known ; 
(4) when the meaning of the word and the real essence are 
not exactly the same. The names of the modes are most lia- 
ble to be doubtful and imperfect for the two first reasons, and 
those of substances for the two second. § 6. When the idea 
of the modes is very complex, as that of the majority of the 
terms of ethics, they rarely have precisely the same significa- 
tion in the minds of two different persons. § 7. The defect 
also of the models renders these words equivocal. He who 
first invented the word brusquer (to be abrupt with) understood 
thereby what he found to the purpose, without informing those 
who have used it as he of his precise meaning, and without 
having shown them any constant model. § 8. Common use 
regulates sufficiently the sense of words for ordinary conversa- 
tion, but it has no precision ; and the signification most con- 
formed to the peculiar nature of the language is every day 
disputed. Many speak of glory, but few have the same under- 
standing of it. § 9. They are only simple sounds in the 
mouths of many, or at least their meanings are very indefinite. 
And in a discourse or conversation in which mention is made 



en. ix] ON HUMAN UNDERSTANDING 371 

of honor, faith, grace, religion, the church, and above all in dis- 
cussion, yon will notice at once that men have different notions 
which they apply to the same terms. And if it is difficult to 
understand the meaning of the terms of the people of our 
time, it is much more difficult to understand ancient books. 
Fortunate is it that we may pass them by save when they 
contain what we should believe and do. 

Th. These remarks are good : but in regard to ancient books, 
as we need to understand Holy Scripture above all, and as 
Roman laws are still of great use in a good part of Europe, we 
are indeed compelled to consult a great many other ancient 
books ; the Rabbis, the Church Fathers, even the profane his- 
torians. Besides the ancient physicians also deserve to be 
understood. The practice of medicine by the Greeks came 
through the Arabs to us ; the water from the fountain has been 
made turbid in the streams of the Arabs, and purified in many 
respects since we have begun to have recourse to the original 
Greeks. But these Arabs do not cease to be of use and we are as- 
sured that Ebenbitar, 1 for example, who in his books on Simples 
has copied Dioscorides, often serves to throw light upon him. I 
find also that, next to religion and history, it is chiefly in medi- 
cine, as far as it is empirical, that the tradition of the ancients 
preserved in writing, and in general the observations of another 

1 Ibn-al-Baitar, c. 1197-1218, a distinguished Arabian botanist, — according 
to Poucliet the most learned that the Arabian School has produced, — who 
wrote a general history of simples, or of plants alphabetically arranged, a 
materia medica, based upon and said to contain for the most part the work of 
the Greek physician Dioscorides, c. 100 a.d., iiepi "YAr,; 'larpiK^, as well as a 
variety of facts from other sources, including descriptions of plants not men- 
tioned by either Dioscorides or Pliny the Elder, 23-79. Most of Baitar's 
works still remain in MSS. in the libraries of Paris and the Escurial. Fr. R. 
Dietz published a small fragment of the work on Simples in his Analecta me- 
dica ex libris MSS., Lipsiae, 1833, 8vo. There are also Grosse Zusammenstel- 
lung u. d. Krafte d. bekannt. einfachen Heil-und-Nahrung&mittel v. __. . . Ebn 
Baithar. Aus d. Arabischen ubersetzt v. Dr. Joseph v. Sontheimer, 2 vols., 
Stuttgart, 1840^2, and Traite des simples, trans, by L. Leclerc, in lust, de 
France, Notices et extraits des MSS. de la Bibl. Nationale, vol. 23, Pt. I., Paris, 
1877, 4to. For some account of Baitar, cf. Leclerc in Gazette hebdom. de medi- 
cine et de chirurgie, sxii., 97, 129, Paris, 1875; F. A. Pouchet, Histoire des sciences 
naturelles au moyen age, Paris, 1853, 8vo. Schaarschmiclt says that Leibnitz 
may have been led to the remark which he here makes upon Baitar by the 
JSxercitationes de homonymis hyles iatricse, appended to Claud. Salmasins, 
1588-1G53, Pliniansa exercitationes, P. 101. a. B. 110. a. A., Trajecti-ad-Rhenum, 
1689, 2 vols., fob, where different accounts of Dioscorides are amended from 
Ebnbitar. — Tr. 



372 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

may be of service. I have therefore always held in high 
esteem physicians much versed in the knowledge of antiquity ; 
and I was very sorry that Reinesius, 1 excellent in both depart- 
ments (of knowledge), had turned aside to explain the rites 
and history of the ancients, rather than to recover a part of 
the knowledge they had of nature, in which it has been shown 
that he would have been able furthermore marvellously to suc- 
ceed. When the Latins, Greeks, Hebrews and Arabs shall 
some day be exhausted, the Chinese, supplied also with ancient 
books, will enter the lists and furnish matter for the curiosity 
of our critics. Not to speak of some old books of the Persians, 
Armenians, Copts and Brahmins, which will be unearthed in 
time so as not to neglect any light antiquity may give on doc- 
trines by tradition and on facts by history. And if there were 
no longer an ancient book to examine, languages would take 
the place of books and they are the most ancient monuments 
of mankind. In time all the languages of the world will be 
recorded and placed in the dictionaries and grammars, and 
compared together ; this will be of very great use both for the 
knowledge of things, since names often correspond to their 
properties (as is seen by the names of plants among different 
peoples), and for the knowledge of our mind and the wonder- 
ful variety of its operations. Not to speak of the origin of 
nations, which is known by means of solid etymologies which 
the comparison of languages will best furnish. But of this I 
have already spoken. And all this shows the use and extent 
of criticism, little considered by some otherwise very clever 
philosophers who take the liberty to speak with contempt of 
Rabbinage 2 and in general of philology. We see also that 
critics will find for a long time yet matter for fruitful exercise, 

1 Thomas Reinesius, 1587-1667, a physician who wrote on natural history 
and medicine, and afterwards devoted himself to philological and antiquarian 
studies. Among his works were, Schola jureconsultorum medica relationum 
libris aliquot comprehensa, quibiis principia medicinse in jus transmuta ex 
pro/esso examinantur, Lipsiae, 1679, 12mo; Syntazma inscriptionem antiquarum 
cum primis Romse, veteris, quorum omissa est recensio in Gruteii opere, cum 
comment, Lipsise, 1682, fol. Of. B. Schuchardt, Lebensbeschreibungen be- 
riihmter jErzte und Naturforscher, ivelche aus Thuringen stammen. Gorre- 
spondenz-Blatter des cdlgemeinen arztlichen Vereins von Thicringen, Weimar, 
1888, xvii., 556, 601. — Tr. 

2 A term of disparagement, meaning the study made of the hooks of the 
rabbis. — Tr. 



ch. ix] ON HUMAN UNDEESTANDING 373 

and they will do well not to amuse themselves too much with 
minutiae, since they have so many objects more pleasing for 
treatment ; though I well know that minutiae also are often very 
necessary with the critics for the discovery of more important 
knowledge. And as criticism turns in large measure upon the 
meaning of words and the interpretation of authors, especially 
the ancients, this discussion about words joined with the men- 
tion you made of the ancients, makes me touch upon this 
important point. But to return to your four defects of nomi- 
nation, I tell you, sir, that we can remedy them all, especially 
since writing has been invented and they subsist only through 
our negligence. For it depends upon us to fix their meanings, 
at least in any scholarly language, and to agree to destroy this 
tower of Babel. But there are two defects where the remedy 
is more difficult, consisting the one in the doubt which exists 
whether the ideas are compatible, when experience does not 
furnish them all combined in one and the same subject ; the 
other in the necessity for making provisional definitions of 
sensible things, when our experience with them is insufficient 
for more complete definitions : but I have spoken more than 
once of both these defects. 1 

Ph. [I am going to tell you some things which will serve 
further to clear up to some extent the defects you have just 
remarked, and the third of those which I have indicated 
makes it seem that these definitions are provisional ; viz. : — 
when we have no sufficient knowledge of our sensible models, 
i.e. the substantial beings of corporeal nature. This defect 
also makes us ignorant as to whether we may combine the 
sensible qualities which nature has not combined, because at 
bottom we do not understand them.] Now if the signification 
of the words which serve for the mixed modes is uncertain, 
for lack of models which show the same composition, that of 
the names of the substantial beings is uncertain for a wholly 
contrary reason, because they must signify what is supposed to 
be conformed to the reality of things, and to be related to the 
models formed by nature. 

Th. I have already more than once remarked in our pre- 
vious conversations that this is not essential to the ideas of 

1 Of. New Essays, Bk. III., chap. 6.— Tr. 



374 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

substances ; but I admit that ideas made after nature are the 
surest and most useful. 

§ 12. Ph. When then we follow the models wholly made 
by nature, unless the imagination finds it necessary to retain 
their representations, the names of substances have in ordi- 
nary use a double relation, as I have already shown. The 
first is that they signify the internal and real constitution of 
things, but this model cannot be known and consequently can- 
not serve to regulate the significations. 

Tli. That is not the question here, since we are speaking of 
ideas of which we have models ; the internal essence is in the 
thing, but we agree that it cannot serve as a pattern. 

§ 13. Ph. The second relation is then that which the names 
of substances immediately have to the simple ideas, which 
exist at the same time in the substance. But as the number 
of these ideas united in one and the same subject is great, men 
speak of this same subject, forming very different ideas of it, 
both by the different combination of the simple ideas they 
make and because the greater part of the qualities of bodies 
are the powers which they have of producing changes in 
other bodies and receiving them ; witness the changes one of 
the basest metals is capable of undergoing through the opera- 
tion of fire, and it receives many more yet at the hands of a 
chemist, through the application of other bodies. Further, one 
is contented with weight and color as criteria for a knowledge 
of gold ; another includes ductility, fixedness ; and the third 
desires to make us take into consideration its solubility in 
aqua regia. § 14. As things likewise often resemble each 
other, it is sometimes difficult to designate their precise 
differences. 

Th. As bodies are really liable to be altered, disguised, 
falsified, counterfeited, it is a great point to be able to dis- 
tinguish and recognize them. Gold is disguised in solution, 
but it may be drawn off, either by precipitating it or dis- 
tilling the water ; and counterfeit or adulterated gold is 
recognized or purified by the art of the assayers, which not 
being known to everybody, it is not strange that men do not 
all have the same idea of gold. And ordinarily ' it is only 
the experts who have sufficiently just ideas of these mat- 



en. ix] ON HUMAN UNDERSTANDING 375 

§ 15. Ph. This variety does not, however, cause so much 
confusion in civil intercourse as in philosophic researches. 

Th. It would be more tolerable if it had no influence in prac- 
tical life where it is often important not to receive a Qui pro 
quo, and consequently to know the characteristics of things or 
to have at hand the class who know them. And it is especially 
important as regards drugs and materials which are costly, and 
of which you may have need on important occasions. The 
philosophical confusion will manifest itself rather in the use 
of more general terms. 

§ 18. Ph. The names of simple ideas are less liable to equivo- 
cation, and we are rarely mistaken as regards the terms white, 
bitter, etc. 

Th. It is, however, true that these terms are not wholly 
exempt from uncertainty ; and I have already noticed the 
example of neighboring colors which are within the confines of 
two species and whose species is doubtful. 

§ 19. Ph. After the names of simple ideas, those of the simple 
modes are least doubtful, as for example, those of figures and 
numbers. But, § 20. the mixed modes and substances cause all 
the trouble. § 21. Men will say that instead of imputing 
these imperfections to the words, we should rather put them 
to the account of our understanding ; but I reply that words 
interpose themselves to such an extent between our mind and 
the truth of things, that we may compare them with the 
medium, across which pass the rays from visible objects, and 
which often spreads a mist before our eyes ; and I have tried 
to think that, if the imperfections of language were more 
thoroughly examined, the majority of the disputes would cease 
of themselves, and the way to knowledge and perhaps to peace 
would be more open to men. 

Th. I think we could succeed from this time in written dis- 
cussions, if men would agree upon certain rides and execute 
them with care. But in order to proceed exactly viva voce and 
at once, some change in the language would be necessary. I 
have elsewhere 1 entered upon this enquiry. 

1 In his writings in furtherance of his plan for the establishment of a General 
Characteristic or Philosophical Language, Specieuse generale, a project which 
Leibnitz had very much at heart, as appears from his frequent allusion to the 
subject, and upon which throughout his entire life he spent much labor, chiefly 



376 LEIBNITZ'S CRITIQUE OE LOCKE [bk. m 

§ 22. Ph. While waiting for this reform which will not be 
ready very soon, this uncertainty regarding words should teach 
us to be moderate, especially when it is a question of imposing 
upon others the sense attributed by us to the ancient authors, 
since in the Greek authors it is found that nearly every one 
speaks a different language. 

Th. I have been rather surprised to see that Greek authors 
so distant from one another in time and place, as Homer, 
Herodotus, Strabo, Plutarch, Lucian, Eusebius, Procopius, 
Photius, approach so closely, while the Latins have changed 
so much, and the Germans, English, and Erench much more. 
But the fact is, the Greeks since Homer's time, and still 
more when Athens was in a flourishing condition, had good 
authors which posterity has taken as models, at least in writ- 
ing. For no doubt the common language of the Greeks must 
have been much changed already under the rule of the Eomans. 
And this same reason accounts for the fact that the Italian 
has not suffered so great a change as the Erench, because the 
Italians, having had earlier writers of durable reputation, imi- 
tated and moreover esteemed Dante, Petrarch, Boccaccio, and 
other authors at a time when those of the Erench were no 
longer appreciated. 

CHAPTER X 

OF THE ABUSE OF WORDS 

§ 1. Ph. Besides the natural imperfections of language, 
there are some that are voluntary and arise from negligence, and 
it is an abuse of words to use them so badly. The first and most 
palpable abuse is, § 2. that we attach no clear idea to them. Of 
these words there are two classes : the first have never had 
any definite idea, either in their origin or ordinary use. Eor 
the most part philosophical and religious sects have introduced 

preparatory, and with little positive results in accomplishing his plan. Cf. 
New Essays, Bk. IV. chap. 6, § 2, Th., chap. 17, § 13, Th.; Gerhardt, Leibniz, 
philos. Schrift.., 3, 216 ; 4, 27 sq., Erdmann, 6 sq. ; G. 7, 3 sq., E. 82 sq., 669 sq.; 
Trendelenburg, Ueber Leibniz. Entwurf einer allgemeinen Characteristic, in 
his Hislor. Beitrdge z. Philos., vol. 3, pp. 1 sq., Berlin, 1867; L. Neff, G. W. 
Leibniz als Sprachforscher und Etymologe, Pt. II., pp. 13 sq., Heidelberg, 
1870-1.— Tr. 



ch. x] ON HUMAN UNDERSTANDING 377 

them in order to support some strange opinion, or to conceal 
some weak place in their system. They are, however, distin- 
guishing characters in the mouth of members of the party. 
§ 3. There are other words, which in their first and common 
use have some clear idea, but which have since been appro- 
priated to very important matters without attaching to them 
any certain idea. In this way the words wisdom, glory, grace, 
are often in the mouths of men. 

Th. I believe that insignificant words are less in number 
than you think, and that with a little care and good will you 
can fill up their void or fix their indefiniteness. Wisdom 
appears to be nothing else than the science of happiness. 
Grace is a favor done to those who do not deserve it and who 
find themselves in a state where they need it. And glory is 
the fame of the excellence of some one. 

§ 4. Ph. I do not wish now to examine whether there is 
anything to be said in regard to these definitions, but rather to 
notice the causes of the abuse of words. In the first place, we 
learn the words before we learn the ideas belonging to them, and 
children accustomed thereto from the cradle use them in like 
manner during their whole life : the more as they do not cease 
to make themselves understood in conversation, without ever 
having fixed their idea, by using different expressions in order 
to make others understand their meaning. This, however, often 
fills their discourses with a quantity of vain sounds, especially 
in matters concerning morals. Men take the words they find 
in use among their neighbors, and in order not to appear 
ignorant of their meaning employ them confidently without 
giving them a certain sense : and, as in this kind of discourse 
they are rarely in the right, they are also rarely convinced 
that they are wrong; and to wish to draw them from their 
error is to wish to dispossess a vagabond. 

Th. Men in fact take so rarely the necessary trouble to 
understand terms or words that I have more than once been 
astonished that children can learn languages so soon, and that 
men furthermore speak them so accurately ; a view to which 
we attach so little in instructing children in their mother 
tongue and which others think of so little in acquiring clear 
definitions ; the more so as those we learn in the schools do 
not ordinarily concern the words in public use. For the rest, I 



378 LEIBNITZ'S CRITIQUE OF LOCKE [bk. in 

admit that men frequently happen to be wrong when indeed 
they discuss seriously and speak in accord with their feeling ; 
but I have also remarked often enough that in their speculative 
discussions upon matters within the province of their mind, 
they have every reason for two sides, except in the oppositions 
they make to each other where they misconstrue another's 
view. This arises from the bad use of terms and sometimes 
also from a spirit of contradiction and affectation of superi- 
ority. 

§ 5. Ph. In the second place the use of words is sometimes 
inconstant, a practice only too general among scholars. It is 
nevertheless a plain cheat, and if voluntary, is folly or malice. 
If any one so conducted himself in his accounts (as to take an 
X for a V), who, I pray, would have anything to do with 
him ? 

Th. This abuse being so common not only among scholars 
but also in the world at large, I believe that it is due rather to 
bad custom and inadvertence than to malice. Usually the 
different significations of the same word have some affinity ; 
this makes one pass for another and does not give time to con- 
sider what is said with all the precision that is desirable. We 
are accustomed to tropes and figures, and some elegance or 
brilliant falsehood easily imposes upon us. For we oftener 
seek pleasure, amusement, and appearance, than truth ; besides, 
vanity mixes itself therein. 

§ 6. Ph. The third abuse is an affected obscurity, either by 
giving terms in use unusual meanings, or by introducing new 
terms without explaining them. The ancient Sophists, whom 
Lucian ridicules so properly, pretending to speak of every- 
thing, covered their ignorance under the veil of the obscurity 
of words. Among the sects of philosophers the Peripatetic 
has shown itself remarkable by this defect ; but the other 
sects, even among the moderns, are not wholly exempt from it. 
For example, the people who abuse the term extension, and 
find it necessary to confuse it with that of body. § 7. Logic 
or the art of discussion, which is held in such high esteem, 
has helped to maintain this obscurity. § 8. Those who 
have given themselves up to it have been useless or rather 
detrimental to the state ; § 9. while mechanics, though de- 
spised by the learned, have been serviceable to human life. 



OH. x] ON HUMAN TTNDEKSTANDING 379 

But these obscure doctors have been admired by the ignorant ; 
and they have been thought invincible because provided with 
briers and thorns, into which it was no pleasure to thrust one's 
self, their obscurity alone serving as a defence of their absurd- 
ity. § 12. The evil is that this art of obscuring words has 
confused the great rules of men's action, religion and justice. 

Th. Your complaint is largely just : it is nevertheless true 
that there are, though rarely, pardonable and even praiseworthy 
obscurities, as when we profess to be enigmatical, and the 
enigma is timely. Pythagoras : so used it, and it is frequently 
the manner of the Orientals. J The alchemists, who are called 
adepts, declare that they wish to be understood only by the 
sons of the art. And that would be well, if these pretended 
sons of the art had the key to the cipher. A certain obscurity 
may be allowed; but something must be concealed which is 
worth divining, and the enigma must be decipherable. But 
religion and justice demand clear ideas. It seems that the 
little order brought into their teaching has made the confusion 
in their doctrine ; and the indeterminateness of the terms is 
perhaps more harmful than their obscurity. Now as logic is 
the art which teaches the order and connection of thoughts, I 
do not see any reason for blaming it. On the contrary it is for 
want of logic that men deceive themselves. 2 

§ 14. Ph. The fourth abuse is when we take words for things, 
i.e. believe that the terms correspond to the real essence of the 



1 Pythagoras, c. 580-570-c. 500 b.c. The reference is to his so-called Symbols, 
or sayings preserved in a symbolic form, in order that their meaning might be 
concealed from the uninitiated, and the characteristic of which is the union of 
au ethical prescript with an external actiou relatively indifferent. Cf. Dioge- 
nes Laertius, Be vitis, dogmatibus, et apophthegmatis clarorumphilosophorum, 
VIII, 17 sq., who gives some of these symbols with interpretations of a part of 
them; Zeller, Philos.d. Griec, 5th ed.,1892, Vol.1, p. 324, note 2,462. Mullach, 
Fragmt. Philos. Grsee., Vol. 1, p. 504 sq., gives a collection of these sayings. 
Examples are: "Carry not the image of God in the finger-ring," "Stir not 
the fire with the sword," " Sacrifice and pray with bare feet." Gottling, 
Gesammlt. Abhandl., Vol. 1, p. 278 sq., 2, 280 sq., has given them a "pene- 
trating investigation," on which see the note of Zeller above cited. Leibnitz 
on Pythagoras, cf. Gerhardt, Leibniz, philos. Schrift., 7, 147. — Tk. 

2 Leibnitz, while rejecting the over-refinements of the scholastic logic, never- 
theless rightly values formal logic as an aid to clear thinking and correct 
reasoning. Cf. the letter to Gabriel Wagner, 1696, Gerhardt, Leibniz, philos. 
Schrift., 7, 512 sq., Erdmann, 418 sq., Guhrauer, Leibniz, deutsche Schrift., 1, 
374 sq., Berlin, 1838. — Tr. 



380 LEIBNITZ'S CEITIQUE OF LOCKE [bk. hi 

substances. Who is there brought up in the Peripatetic phi- 
losophy who does not think that the ten names which represent 
the predicaments are exactly conformed to the nature of things ; 
that the substantial forms, vegetative souls, abhorrence of a vacuum, 
intentional species, etc., are something real ? The Platonists 
have their soul of the world, and the Epicureans the tendency of 
their atoms towards movement at the time when they are at 
rest. If the aerial or ethereal vehicles x of Dr. More had pre- 
vailed in any corner of the world they would have been thought 
no less real. 

Th. Properly speaking this is not to take words for things, 
but to believe that true which is not so, an error too common 
with all men, depending not alone upon the abuse of words, 
but consisting in something entirely different. The design 
of the predicaments is a very useful one, and we ought to 
think of rectifying rather than of rejecting them. Substances, 
quantities, qualities, actions or passions, and relations, i.e. five 
general names of things may, together with those formed by 
their composition, suffice, and have not you yourself, in mar- 
shalling ideas, been willing to grant them as the predicaments ? 
I have spoken above of substantial forms. 2 And I know not 
whether we have sufficient reason for rejecting the vegetative 
soids, 3 since persons of much experience and judgment recog- 

1 The aerial or ethereal vehicles are the aerial or celestial bodies of the 
spirits, which, according to More, the souls of men after sufficient purification 
attain, either at death, in the case of a very few of the noblest and most 
heroic, or at some period after death. Cf. H. More, Opera omnia, Loudini, 
1679, 2 vols., fol. ; Tract, de immortalitate animse, Bk. III. chap. 1, Axioma, 27, 
§§ 3, 28 sq., Vol. 2, p. 396 sq., chap. 11, § 2, p. 427 ; Antidotus adversus Atheis- 
mum, Bk. III. chap. 3, § 9, Vol. 2, p. 99. — Te. 

2 Cf. ante, p. 349 and note. — Tr. 

3 The scholastic philosophy recognized three forms or kinds of souls, corre- 
sponding to the three orders of life, plants, animals, and men, viz.: the vege- 
tative, sensitive, and intellective (anima vegetabilis or nutritiva, sensibilis or 
sensitiva, intellectiva or rationalis). Of these the vegetative is the lowest, 
the sensitive the next higher, the intellective the highest; and the higher 
form includes potentially in itself the lower and subordinate form and its 
functions. The functions of the vegetative soul are nutrition, growth, repro- 
duction ; of the sensitive soul, sensation, feeling, perceptional, appetitive and 
emotional activity ; of the intellective, those of the reason and the will. In 
man, these several functions are all united in the intellective or rational soul, 
which he alone possesses, and which comprises within itself the sensitive and 
vegetative souls. Cf. Stockl, Gesch. d. Philos. d. Mittelalters, II. 2 [Vol. 31, 
592 sq., 618 sq., 633 sq. — Tr. 



en. x] ON HUMAN UNDERSTANDING -881 

nize a great analogy between plants and animals, and you, sir, 
have appeared to admit animal souls. - Abhorrence of a vacuum 
may be soundly understood; i.e. supposing nature lias once 
filled space, and that bodies are impenetrable and non-condens- 
able, she could not admit any vacuum ; and I consider these 
three suppositions well grounded. But the intentional species, 1 
which are to make the connection between the soul and the 
body, are not so, though we may excuse the sensible species, 1 

i Cf. 5th letter of Leibnitz to Clarke, § 84, Gerharclt, 7, 410, Erdmann, 773, 
b, Jacques, 2, 465, Dutens, 2, Pt. I, 161, trans. Duncan, 275. 

The doctrine of the intentional species {species intentionales) to which 
were opposed the real species (species reales) or the actual forms of things, 
arose in the attempts of the Mediaeval Schoolmen to explain the process and 
philosophy of seuse-perception and cognition. Two views have in general been 
held concerning their nature: 1. That they were the forms, similitudes, or 
images (formie, similitudines, simulacra) of external objects, different both 
from the mind and from these objects, the intermediate and vicarious repre- 
sentatives of these objects in perception and thought, the media through 
which the mind infers and comes to know these external objects — a form of 
the doctrine of mediate perception. 2. That they were modifications of the 
mind itself, occasioned by the action upon the mind of the external object and 
the mind's responsive reaction thereto, by which the mind is likened or con- 
formed to the given object and so determined immediately to cognize it. 
The latter view is maintained by the Roman Catholic psychologists, as being 
the doctrine of the greatest of the schoolmen, such as Albertus Magnus, 
Thomas Aquinas, Duns Scotus, and as giving the real meaning of the terms 
they use. It is the more correct interpretation. 

The intentional species, according as they affected or were modifications of 
the sense or the intellect, were divided into sensible species (species sensibiles) 
and intelligible or intellectual species (species intelligibiles vel intellectuales) . 
Both the sensible and the intelligible species were further distinguished as 
impressed species (species impressa) and expressed species (species expressa). 
According to the representative theory of the intentional species, the species 
impressa was the vicarious existence emitted by the object, impressed on the 
particular faculty, and concurring with it in its operation ; while the species 
expressa was the actual operation elicited by the faculty and the impressed 
species coujointly, i.e. the sensations and intellections. The direct or imme- 
diate theory regarded the genesis of species, whether as sensible or intelligible, 
as exhibiting two stages : 1. In sensuous cognition, (a) the species sensibilis 
impressa, or "the modification of the sensuous faculty viewed as an impres- 
sion wrought in the mind by the action of the object," and (b) the species 
sensibilis expressa, or "the reaction of the mind as an act of cognitive con- 
sciousness." 2. In intellectual cognition, (a) the species intelligibilis im- 
pressa, or the "modification effected in the recipient capacity" of the 
intellectus patiens vel possibilis (the passive intellect — Aristotle's vov<; n-aflrjTi- 
k6s), and (b) the species intelligibilis expressa, or the "mental modification 
reflecting the essence of the object, and by means of which the object is ap- 
prehended," a modification due to the act of the intellectus agens (the active 
intellect — Aristotle's vovs ttoitji-iko?). 



382 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

which proceed from the object to the distant organ, meaning 
thereby the propagation of motion. - I admit that there is no 
Platonic soul of the world, for God is beyond the world, extra- 
mundana intelligentia, or rather supramundana. 1 v I know not 
whether by the tendency to movement of the Epicurean atoms 
you understand the weight attributed to them, no doubt with 
reason, since they maintain that bodies all move of them- 
selves in one and the same direction. The late Henry More, a 
theologian of the English Church, wholly clever as he was, 
showed himself a little too ready to invent hypotheses which 
Avere neither intelligible nor apparent; witness his Hylarchic 
principle 2 of matter, a cause of weight, elasticity, and other 
wonders which are met with. I have nothing to say of these 
ethereal vehicles, having never examined their nature. 

§ 15. Ph. An example touching the word matter will assist 
you the better to enter into my thought. Matter is taken as 



The doctrine of the intentional species was held by the Realists, Aquinas, 
Duns Scotus, and others. The Nominalists, especially Durandus, Biel, and 
Occam, rejected it, and the doctrine was exploded in the seventeenth century, 
largely by the arguments of Gassendi, Hobbes, and Descartes. On the whole 
subject, cf. Hamilton's Held, 8th ed., Edinburgh, 1880, Vol. 1, p. 267 sq., and 
Note M., Vol. 2, p. 951 sq. ; Lects. on Metaphys., Boston, 1875, p. 291 sq., and 
notes; Stockl, Gesch. d. Philos. d. Mittelalters, II. 1 [Vol. 2] 463 sq., II. 2 
[Vol. 3] 808, 965, 978, 991 sq., III. [Vol. 4] 634 sq. ; Haure'au, Histoire de la 
philos. scolastique, II. 1 [Vol. 2] 417 sq., II.. 2 [Vol. 3] 247 sq., 378 sq. ; Prantl, 
Gesch. d. Logik im Abendlande, Vol. 3, pp. 113, 210 sq., 294, 335 sq. ; Maher, 
S. J., Psychology (Manuals of Catholic Philosophy — Stonyhurst Series) , pp. 
49-53, 290-297, London: Longmans, Green & Co., 1890; Zigliara, Summa 
Philosophica, 3d ed., Lugduni, 1880, Vol. 2, pp. 243-4, 260 sq. ; Suarez, De 
Anima, Lib. III. cc. 2, 3; Kleutgen, Philos. d. Vorzeit, §§ 18-52; Sanseverino, 
Dynamilogia, Neapoli, 1862-66, Vol. 1, pp. 373-403 (of which pp. 390-100 
contain " an effective refutation of the charge of representationism against 
St. Thomas and the leading scholastics, based on the doctrine of species"), 
Vol.2, pp. 5S6 sq. — Tr. 

1 Cf. The'odicee, Pt. II. § 217, Gerhardt, 6, 248, Erdmann, 571, a, Jacques, 2, 
205. — Tr. 

2 Cf. Gerhardt, Leibniz, philos. Schrift., 7, 339 ; letter to Placcius, Sept. 8, 
1690, Dutens, Leibnit. op. om., 6, 48; to T. Burnett, Aug. 24 (v.s.) 1697, G. 3, 
217, D. 6, 263. More rejected the mechanical explanation of physical nature, 
and adopted the principium hylarchicum, or spiritus natures as he designates 
it, the immaterial force in all nature, the principle of the movement and 
sympathy of beings, similar to the anima mundi of the Platonists and the 
archseus (cf. ante, p. 67, note 3) of the Alchemists. Cf. H. More, Opera omnia, 
Londini, 1679, Enchiridion metaphys., especially in the Scholia, to chap. 13, 
§ 4, Vol. 1, p. 222 sq. ; also Tract, de immortalitate animse, Bk. III. chap. 12, 
Vol. 2, p. 430. — Tr. 



en. x] ON HUMAN UNDERSTANDING 383 

an entity really existing in nature, distinct from the body; 
which indeed is thoroughly self-evident ; otherwise these two 
ideas might be put indifferently the one in the place of the 
other. For we may say that one single matter composes all 
bodies, but not that a single body composes all matter. 
Neither will we say, I think, that one matter is greater than 
another. Matter expresses the substance and solidity of 
body ; thus we no more conceive different matters than differ- 
ent solidities. But since matter has been taken as a name of 
something existing under this determination, this thought has 
produced unintelligible discourse and confused discussion upon 
materia prima. 

Th. This example appears to me to serve rather to excuse 
than to blame the Peripatetic philosophy. If all silver were 
figured, or rather because all silver is figured by nature or art, 
is it less allowable to say that silver is an entity really existing 
in nature, distinct (taking it in its precision) from the plate or 
the money ? You will not on that account say that silver is 
nothing else than certain qualities of money. Thus it is not 
so useless as you suppose to reason in general physics about 
materia prima and to determine its nature in order to know 
whether it is always uniform, whether it has some other 
property besides impenetrability (as I in fact have shown * 
after Kepler that it also has what may be called inertia), etc., 
although it is never found wholly pure ; as it would be allow- 
able to reason about pure silver, although we had none with us 
nor the means of purifying it. I do not at all disapprove 
what Aristotle has said about materia prima; 2 but one cannot 

1 Cf. Be ipsa natura, 1698, § 11, Gerhardt, Leibniz, philos. Schrift., 4, 510, 
Erdmann, 157, a, Jacques, 1, 462 (in French), Dutens, 2, Pt. II., 54, trans. 
Duncan, 119; Theodicee, Pt. I., § 30, G. 6, 119, E. 512, a, J. 2, 89, Dutens, 1, 
141 (in Latin) ; Specimen dynamicum, 1695, Pt. I., Gerhardt, Leibniz, math. 
Schrift., 6, 234 sq., Dutens, 3, 315 sq., trans. Appendix, 670 sq. ; G. Leibniz. 
philos. Schrift., 4, 464-7, Dutens, 2, Pt. I., 234-7, two letters to the editor of the 
"Journal des Savans," in the numbers for June 18th, 1691, January, 1693, the 
first originally a fragment from a letter to Antonio Alberti, G. 7, 447-9 ; 5th 
letter toClarke, § 102, G. 7, 414, E. 775, h, J. 2, 470, Dutens, 2, 165, trans. Duncan, 
280. In the letter to Jac. Thomasius, April 20-30, 1669 {cf. G. 1, 17, 18, 24), 
Leibnitz affirmed that matter consisted of extension and inpenetrability only. 
— Tr. 

2 Cf. Zeller, Philos. d. Griech., 3d ed., 1879, II. 2 [Vol. 4] , p. 320, note 2 ; and 
Bonitz, Ind. Arist. sub voc. v\-q, in vol. 5 of Berlin Academy, ed. of Aristotle. 
Cf. also Gerhardt, Leibniz, philos. Schrift., 7, 259. — Tr. 



384 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

help blaming those who have stopped too soon and have con- 
jured up chimeras out of the ill-understood words of this 
philosopher, who perhaps also has given too much occasion 
sometimes for this misconception and nonsense. But we 
should not exaggerate so much the defects of this celebrated 
author, because we know that many of his works were not 
completed or published by himself. 

§ 17. Ph. The fifth abuse is the putting of words in the place 
of things which they do not and cannot in any way signify. 
It occurs when by the names of substances we mean to say 
something more than this : what I call gold is malleable 
(although at bottom then gold signifies nothing else than what 
is malleable), intending to have it understood that mallea- 
bility depends upon the real essence of gold. Thus we say 
that it is right to define man with Aristotle as a reasonable 
animal; and that it is not right to define him with Plato 
as a two-legged animal without feathers and with broad nails. 
§ 18. There is scarcely any one who does not suppose that 
these words signify a thing having a real essence upon which 
these properties depend; but it is a plain abuse when the 
complex idea signified by this word does not include this thing. 

Th. For myself I should rather think that we are plainly 
wrong in censuring this common usage, since it is very true 
that in the complex idea of gold is included the thought that 
it is a thing having a real essence, whose constitution is un- 
known to us in detail otherwise than that upon it depend such 
qualities as malleability. But in order to express its mallea- 
bility without identity and without the defect of coccysm or 
repetition (see chap. 8, § 18), l we must recognize this thing by 
other qualities, as color and weight. And it is as if we said 
that a certain fusible body, yellow and very heavy, called gold, 
has a nature which gives it besides the quality of being very 
soft to the hammer and capable of being made very thin. As 
for the definition of man attributed to Plato, which he appears 
to have made only for practice, and which you would not, I 
think, compare seriously with that which is received, it is 
manifestly a little too external and provisional; for if this 
Cassowary, of which you recently spoke (chap. 6, § 34), had 

1 The reference is incorrect. Perhaps chap. 6, § 18, is meant, or chap. 10, 
§ 18.— Tr. 



oh. x] ON HUMAN UNDERSTANDING 385 

been found to have wide nails, it would be man ; for it would 
not have been necessary to strip it of its feathers, as in the 
case of the cock which Diogenes, as they say, wished to make 
a Platonic man. 1 

' § 19. Ph. In the mixed modes, as soon as an idea entering 
therein is changed, you at once recognize it as another thing, 
as plainly appears in the words, murder, which signifies in 
English (as Mordt in German), homicide premeditated with 
design ; manslaughter (a word corresponding in origin to homi- 
cide), a voluntary but not premeditated homicide; chance- 
medley (a chance melee, according to the force of the word), 
homicide committed without design ; for what is expressed by 
the names and what I think to be in the thing (which I called 
before nominal essence and reed essence) is the same. But it is 
not so in the names of substances ; for if one puts into the idea 
of gold what another leaves out, for example fixedness and 
solubility in aqua regia, men do not think for that reason that 
its species has been changed, but only that the one has a more 
perfect idea than the other of what constitutes the real con- 
cealed essence to which the name of gold is given, although this 
secret relation is useless and serves only to involve us in diffi- 
culties. 

Th. I think I have already made this statement ; but I am 
going also to show you clearly here, that what you, sir, have 
just said, is found in the modes, as in the substances, and that 
we have no ground for censuring the internal essence for this 
relation. Here is an example : we may define a parabola, in 
the sense of the geometers, as a figure in which all the lines 
parallel to a certain straight line are united by thought in a 
certain point or focus. But it is rather the exterior and the 
effect which is expressed by this idea or definition, than the 
internal essence of this figure or what can at once make known 
its origin. We may at the beginning even doubt if such a 
figure as we wish and which ought to produce this effect is a 
possible thing ; and it is this which with me shows whether a 

1 Cf. Diogenes Laertius, c. 230-250, Be vitis, dogmatibus et apophthegmatis 
clarorum philosophorum lib. decern, VI. 40: HAonwos bpia-a.fi.ivov, "Av0pw7ro ; earl 

£u>ov Sinovv, amtpov, ko.\ evoOKinoiivTOs, Ti'Aas [AioyeV?)? 6 kuW] a\exTpv6va eiar/vtyKiiV ei? 
Triv ctxoAtji' aurov, k<u <f>7jcrii', OCrd? io~Tiv 6 nAaTwi'OS avOpwiros. b9ev Tc3 bpto irpoo-ereffT) 

Tb nKaTvuvvxov. The definitions ascribed to Plato, and found in some editions 
of his works, are beyond doubt spurious. — Tr. 
2c 



386 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

definition is only nominal and taken from the properties, or 
whether it is also real. But he who mentions the parabola 
and knows it only by the definition I have just spoken of, 
ceases not, when speaking of it, to understand a figure which 
has a certain construction and constitution unknown to him, 
but which he wishes to learn in order to be able to draw it. 
Another who has examined it more thoroughly will add some 
other property, and will discover, for example, that in the 
figure asked for, the portion of the axis intercepted between 
the ordinate and the perpendicular drawn to the same point 
of the curve is always constant, and equal to the distance 
from the vertex to the focus. He will thus have a more per- 
fect idea than the former, and will come more easily to the 
drawing of the figure, although he is not yet there. And, 
moreover, we shall agree that it is the same figure, the consti- 
tution of which is still concealed. You see then, sir, that all 
that you have found and partly censured in the use of words 
signifying substances is also found and found plainly justified 
in the words signifying the mixed modes. But what has made 
you think that there was some difference between the sub- 
stances and the modes, 1 is merely the fact that you have not 
consulted here the intellectual modes difficult of discussion, 
which are found to resemble in all this bodies which are still 
more difficult to know. 

§ 20. Ph. Thus I fear I must suppress what I wished 
to say to you, sir, of the cause of what I have thought an 
abuse, as if it were because we falsely think that nature 
always acts with regularity and fixes limits to each species by 
this specific essence or internal constitution which we there 
understand and which always follows the same specific name. 

Th. You see clearly then, sir, by the example of the geo- 
metrical modes, that we are not wrong in referring them to 
internal and specific essences, although there is great differ- 
ence between sensible things, whether substances, or modes, 
of which we have only nominal provisional definitions, and 
of which we do not readily hope for real ones, and between 
the intellectual modes, difficult of discussion since we can at 
last reach the internal constitution of the geometrical figures. 

1 Jacques reads : " c'est que vous n'avez point consulte," etc. Gerkardt and 
Erdmann read: " n'est que vous," etc. — Tr. 



ch. x] ON HUMAN UNDERSTANDING 387 

§ 21. Ph. [I see at last that I should have been wrong in 
laying the blame of this relation upon the essences and internal 
constitutions, under the pretext that this would render our 
words signs of nothing or of an unknown something. For 
what is unknown in certain respects may make itself known 
in another way, and the inner nature may partly reveal itself 
by the phenomena which spring from it. And as for the 
question : whether a monstrous foetus is a man or not ? I see 
that, if it cannot be decided at once, this fact does not prevent 
the species from being well fixed in itself, our ignorance 
nowise changing anything in the nature of things.] 

Th. In fact, some very clever geometers have chanced to 
possess insufficient knowledge as to what the figures were, 
many qualities of which seemingly exhaustive of the subject 
they knew. For example, there were some lines called pearls, 1 
of which there were given indeed the quadratures and the 
measure of their surfaces and of the solids made by their 
revolution, before it was known that they were only a com- 
position of certain cubic paraboloids. Thus in considering 
beforehand these pearls as a particular species, they had only 
provisional knowledge of them. If this may happen in geom- 
etry, do you wonder that it is difficult to determine the species 
of corporeal nature which are incomparably more complex ? 

§ 22. Ph. Let us pass to the sixth abuse in order to con- 
tinue the enumeration begun, although I see clearly that some 
of the points must be struck from the list. This general but 
little noticed abuse is this : men having by long use attached 
certain ideas to certain words, imagine that this connection is 
manifest and that everybody agrees to it. Whence it comes 
that they feel very strange, when asked the meaning of the 
words they employ, when indeed the question is an absolutely 
necessary one. There are few people who do not take it as an 

1 Of. Neio Essays, Bk. IV., chap. 7, § 4, Th. infra, p. 465. Rene Francois 
Walter de Sluse, 1622-1685, a Flemish geometer, canon of Liege cathedral, and 
author of the method for the construction of the roots of equations of the 3d 
and 4th degree, "which consists in reducing the resolution of the proposed 
equation to that of the system of two equations representing two conies, hy 
introducing an unknown auxiliary whose elimination reproduces the primitive 
equation." He developed this method in his Mesolabium et problemata solida, 
etc., 4to, Leodii Ehuronum, 1668. Leibnitz mentions this work in a letter to 
Hohbes, 13-22 July, 1670, Gerhardt, Leibniz, philos. Schrift., 7, 573. — Tk. 



388 LEIBNITZ'S CRITIQUE OF LOCKE [bk. hi 

affront if asked what they mean when speaking of life. v But 
the vague idea they may have of it is insufficient when the 
question arises as to the knowledge whether a plant, already 
formed in the seed, or a pullet in the egg not yet in process 
of incubation, or a man in a swoon without sense or motion, 
has life. And although men do not wish to appear so little 
intelligent or so obtrusive as to find it necessary to ask for an 
explanation of the terms used, nor critics so disagreeable as to 
censure others unceasingly for the use they make of words, 
nevertheless when it is a question of exact research, such 
explication is necessary. Often scholars of different parties 
in the reasonings they display the one against the other 
merely speak different languages and think the same thing, 
although perhaps their interests are different. 

Th. I think I have explained sufficiently my views upon 
the notion of life, which must always be accompanied by per- 
ception in the soul ; otherwise it would be only an appearance, 
as the life which the American savages attributed to watches 
or clocks, or which those magistrates attributed to the mario- 
nettes, who believed them animated by demons, when they 
desired to punish as a sorcerer the one who had first pre- 
sented this spectacle in their city. 

§ 23. Ph. In conclusion, words serve (1) to make our 
thoughts understood, (2) to do this easily, and (3) to furnish 
entrance into the knowledge of things. Words fail at the 
first point, when they have no definite and constant idea 
either received or understood by others. § 23. They fail in 
facility, when they have very complex ideas, without distinct 
names ; this is often the fault of the languages themselves 
which have no names ; often also of the man who is ignorant 
of them ; in that case extensive paraphrases are necessary. 
§ 24. But when the ideas signified by the words do not agree 
with what is real, they fail in the third point. § 26. (1) He 
who has terms without ideas is like a man who has only a 
catalogue of books. § 27. (2) He who has very complex ideas 
is like a man who has a quantity of books in loose sheets 
without titles, and who could not give the book save by giving 
the sheets in succession. § 28. (3) He who is not constant 
in the use of signs is like a merchant who sells different goods 
under the same name. § 29. (4) He who attaches particular 



OH. x] ON HUMAN UNDERSTANDING 389 

ideas to received words cannot enlighten others by the light he 
may have. § 30. (5) He who has in his head ideas of sub- 
stances which never had existence, cannot advance in real 
knowledge. § 33. The first will speak in vain of the taran- 
tula or of charity. The second will see new animals without 
being able easily to show them to others. The third will 
take body sometimes as a solid, sometimes as a mere exten- 
sion ; and by frugality he will designate sometimes the virtue, 
sometimes the kindred vice. The fourth will call a mule 
by the name horse, and what everybody calls prodigal will be 
to him generous ; and the fifth will seek in Tartary on the 
authority of Herodotus 1 a nation composed of men having only 
one eye. I remark that the first four defects are common to 
the names of substances and modes, but that the last is pecu- 
liar to substances. 

Th. Your remarks are very instructive. I will only add 
that you seem to have something chimerical still in your ideas 
of the accidents or forms of being ; and so the fifth defect is 
also common to substances and to accidents. The extravagant 
shepherd was not so, only because he believed there were 
nymphs concealed in the trees, but also because he always 
expected romantic adventures. 

§ 34. Ph. I had thought to conclude, but I remember the 
seventh and last abuse, which is that of figurative terms or 
allusions. But there will be difficulty in thinking it an abuse, 
because what is called wit and imagination is better received 
than truth wholly dry. It goes well in discourse where you 
only seek to please; but at bottom, order and clearness ex- 
cepted, all the art of rhetoric, all these artificial and figura- 
tive applications of words, serve only to insinuate false ideas, 
to excite the passions and seduce the judgment, so that they 
are nothing but pure frauds. Nevertheless this fallacious art 
is given the first rank and rewards. It is evident that men 
care but little for truth and much prefer to deceive and to be 
deceived. This is so true that I doubt not that what I have 
just said against this art is regarded as the result of an extreme 
audacity. For eloquence, like the fair sex, has charms too 
powerful to allow itself to be opposed. 

1 Book III., chap. 116; IV.» chaps. 13, 27: cf. also iEschylus, Prometheus, 823 
(801, Dindorf), 3d ed., F. A. Paley, London, 1870; Pausanius, 1, 24, 6. — Tr. 



390 LEIBNITZ'S CRITIQUE OE LOCKE [ek. hi 

Tli. Very far from censuring your zeal for the truth, I 
find it just. And would that it might be effective. I do 
not wholly despair of it, because you seem to me, sir, to combat 
eloquence with its own weapons, and to have an eloquence of 
another species superior to this deceptive kind, as there was a 
Venus Urania, mother of divine love, before whom this other 
bastard Venus, mother of a blind love, dared not appear with 
her child with eyes blinded. 1 But that indeed proves tha/t 
your thesis needs some moderation, and that certain adorn- 
ments of eloquence are like the Egyptian vases which you 
cordd use in the worship of the true G-od. It is as in painting 
and music, which are abused, one of which often represents 
grotesque and even hurtful imaginations, and the other softens 
the heart, and the two amuse in vain ; but they can be usefully 
employed, the one to render the truth clear, the other to make 
it effective, and this last result must be also that of poetry 
which contains rhetoric and music. 



CHAPTEE XI 

OF THE REMEDIES WHICH MAY BE APPLIED TO THE IMPER- 
FECTIONS AND ABUSES JUST SPOKEN OP 

§ 1. Ph. This is not the place to plunge into this discussion 
upon the use of a true eloquence, and still less to reply to your 
obliging compliment, since we ought to think of bringing this 
matter of ivorcls to an end, by seeking the remedies for the 
imperfections we have noticed therein. § 2. It would be ridic- 
ulous to attempt to reform the languages, and to desire to com- 
pel men to speak only according to the measure of their knowl- 
edge. § 3. But it is not too much to desire that philosophers 
speak exactly, when the question concerns a serious search for 
the truth : without this all will be full of error, opiniativeness, 
and vain disputes. § 8. The first remedy is to use no word 

1 For the myth here referred to by Leibnitz, cf. Plato, Symposium, 180, D, 
Jowett's trans. Vol. 2, p. 32, 2d ed., 1875, Vol. 1, p. 550, 3d ed., 1892; Pausa- 
nias, 9, 16, 3 ; also Harrison- Verrall, Mythology and Monuments of Ancient 
Athens, 212 sq., London, Macmillan & Co., 1890; Preller, Griech. My thol., 2d 
ed., 1860, Vol. 1, p. 265. — Tr. 



ch. xi] ON HUMAN UNDERSTANDING 391 

without attaching thereto an idea, instead of frequently em- 
ploying words like instinct, sympathy, antipathy, without 
attaching any sense to them. 

Th. The rule is good ; but I know not whether the examples 
are pertinent. Everybody seems to understand by instinct an 
inclination of an animal to what is proper for it, without on 
that account apprehending its reason ; and men indeed ought 
less to neglect these instincts, which they discover moreover 
in themselves, although their artificial method of living has 
for the most part nearly effaced them ; the physician of his 
own accord, indeed, has carefully observed it. Sympathy or 
antipathy signifies that which in bodies destitute of feeling 
corresponds to the instinct for union or separation found in 
animals. And although we have no such knowledge of the 
cause of these inclinations or tendencies, as is to be desired, 
we nevertheless have a notion of them sufficient to discourse of 
them intelligibly. 

§ 9. Ph. The second remedy is that the ideas of the names 
of the modes at least be determined and, § 10. that the ideas 
of the names of substances be more conformed to what exists. 
If any one says that justice is conduct conformed to the law 
relating to the good of another, this idea is not sufficiently 
determined, so long as we have no distinct idea of that which 
is called law. 

Th. We might say here that the laiv is a precept of wisdom 
or of the science of happiness. 

§ 11. Ph. The third remedy is to employ terms so far as 
possible in conformity with received usage. § 12. The fourth 
is to declare in what sense we take the words, whether we 
coin new ones or employ the old in a new sense, (or) 
whether we find that use has not sufficiently fixed their mean- 
ing. § 13. But there is some difference. § 14. The words for 
simple ideas which cannot be defined, are explained by synony- 
mous words," when they are better known, or by showing the 
thing. It is by these means that we can make a peasant un- 
derstand what the color feuille morte is, by telling him that it is 
that of dry leaves which fall in the autumn. § 15. The names 
of the mixed modes should be explained by definition, for that is 
possible. § 16. It is upon this ground that ethics is suscepti- 
ble of demonstration. We shall take man as a corporeal 



392 LEIBNITZ'S CRITIQUE OF LOCKE [bk. m 

rational being without troubling ourselves about his external 
figure, § 17. for it is by means of definitions that the matters 
of morality may be clearly treated. We shall rather define 
justice according to the idea we have in our mind than 
seek a model therefor outside of us, as Aristides, and form 
it thereupon. § 18. And as the majority of the mixed 
modes nowhere exist together, we can fix them in defining 
them only by the enumeration of that which is scattered. 
-^§ 19. In substances there are ordinarily some directing or 
characteristic qualities which we consider as the most distinc- 
tive idea of the species, to which we suppose the other ideas 
forming the complex idea of the species are attached. It is 
form in vegetables and animals, and color in animate bodies, 
and in some color and form together. This is why, § 20. the 
definition of man given by Plato is more characteristic than 
that of Aristotle ; or why we should not cause the death of 
monstrous productions, § 21. and often sight avails as much 
as any other test; for persons accustomed to test gold often 
distinguish by sight the true from the false, the pure from 
that which has been adulterated. 

TJi. Everything doubtless returns to the definitions which 
may extend even to primitive ideas. One and the same sub- 
ject may have several definitions, but the knowledge that they 
agree with themselves, must be learned by reason, by demon- 
strating one definition by another,\ or by experience, by proving 
that they constantly go together. ^ As for morality, one part is 
wholly grounded in reason ; but there is another depending 
upon experience and related to the disposition. For a knowl- 
edge of substances, form and color, i.e. the visible, gives us 
the first ideas, becaii.se it is by these that we know things 
at a distance ; but they are ordinarily too provisional, and in 
things of importance to us we try to know substance more 
closely. I am astonished, moreover, that you return again to 
the definition of man, attributed to Plato, . since you have just 
yourself stated, § 16. that in morals man must be taken as a 
corporeal rational being without troubling ourselves about the 
external form. Por the rest it is true that a large practice does 
much for discerning at sight what another may scarcely know 
through arduous experiments. And physicians of large experi- 
ence, with very good sight and memory, often know at the first 



OH. xi] ON HUMAN UNDERSTANDING 393 

appearance the disease which another will draw out for himself 
with difficulty by force of questioning and trying the pulse. 
But it is well to unite all the indications we may have. 

§ 22. Ph. I admit that he to whom a good assayer makes 
known all the qualities of gold, will have a better knowledge 
of them than sight could give. But if we could learn its in- 
ternal constitution, the meaning of the word gold would be as 
easily determined as that of the triangle. 

Th. It would be wholly as determined, and it would have in 
it no provisional element ; but it would not be so easily deter- 
mined. For I think a distinction a little prolix would be 
necessary in order to explain the contexture of gold, as is the 
case indeed in geometry with figures whose definition is long. 

§ 23. Ph. Spirits separated from bodies have doubtless 
knowledge more perfect than ours, although we have no notion 
of the manner in which they may acquire it. But they may 
have as clear ideas of the radical constitution of bodies, as we 
have of a triangle. 

Th. I have already remarked, sir, that I have reasons for 
thinking that no created spirits exist entirely separate from 
bodies ; but there are no doubt some whose organs and under- 
standing are incomparably more perfect than ours, and which 
surpass us in every kind of conception, as much and more than 
Mr. Frenicle, 1 or that Swedish boy of whom I have spoken to 
you, surpassed the common run of men in the calculation of 
numbers, made by imagination. 

§ 24. Ph. We have already noticed that the definitions of 
substances which may serve in explaining names are imperfect 
in relation to the knowledge of things. For usually we put 

1 Cf. Gerhardt, Leibniz, philos. Schrift., 4, 319. Bernard Frenicle de Bessy, 
c. 1605-1675, brother of the poet Nicolas Frenicle, 1600-1661, "conseiller a la 
cour des monnaies," member of the Paris Academy of Sciences, who acquired 
the reputation of being the first arithmetician of his age by the rapidity with 
which he solved the most complicated numerical problems, and by his ingen- 
ious researches upon the solution in whole numbers of indeterminate equations. 
' His method, known as the method of exclusions, appears to have been an inge- 
nious groping, but based on some general propositions which greatly restricted 
this groping, and which have since been rigorously demonstrated by Leonard 
Euler, 1707-1783 and Jos. Louis Lagrange, 1736-1813. Pierre de Fermat, 1601- 
1665, and Descartes, 1596-1650, greatly admired his work, astonished that he 
could go so far without the aid of algebra and that his arithmetic could con- 
duct him where analysis finds so much difficulty in going. His principal work 
was, Traite des triangles, rectangles en nombre, Paris, 1676. — ■ Tb. 



394 LEIBNITZ'S CRITIQUE OE LOCKE [dk. in 

the name in the place of the thing ; then the name says more 
than the definitions ; thus to give a good definition of sub- 
stances, we must study natural history. 

Th. You see then, sir, that the name gold, for example, 
signifies not only that which he who pronounces it knows of 
it ; — for example, something yellow, very heavy, — but also 
what he does not know, and which another may know, i.e. a 
body endowed with an internal constitution from which pro- 
ceed color and weight, and from which spring still other prop- 
erties admitted to be better known by experts. 

§ 25. Ph. It were now to be wished that those practised in 
physical researches would set down the simple ideas in which 
they observe that the individuals of each species constantly 
agree. But the composition of a dictionary of this kind 
which would contain, so to speak, a natural history, would re- 
quire too many persons, too much time, trouble, and sagacity 
for such a work ever to be hoped for. It would be well, how- 
ever, to accompany words with small copper-plate engravings 
of things known by their external form. Such a dictionary 
would be of much service to posterity and would spare future 
critics much trouble. Small figures as of the celery-plant 
(apium), of a Bouquetin (ibex, a kind of wild goat), would be 
more valuable than long descriptions of this plant or of this 
animal. And in order to know what the Latins called strigiles 
and sistrum, tunica and pallium, figures in the margin would be 
incomparably more valuable than the pretended synonymes, 
currycomb, cymbal, dress, cloak, mantle, which show but little 
of them. For the rest I shall not stop upon the seventh remedy 
of the abuse of words which is to employ constantly the same 
term in the same sense, or to give notice when you change it. 
For we have spoken sufficiently of this subject. 

Th. Rev. Father Grimaldi, 1 President of the Mathematical 

1 Claudius Philip Grimaldi, with whom Leibnitz became acquainted during 
his stay in Rome in 1689, and with whom he corresponded, receiving from him. 
after his return to Pekin much interesting information. Of. Guhrauer, G. W. 
Freiherr v. Leibniz, 2, 95 sq. ; Kuno Fischer, Gesch. d. n. Philos., Vol. 2, p. 201, 
3d ed., Heidelberg, 1889; Dutens, Leibniz, op. om., 4, Pt. I. 81, 83 sq., 88; 6, 
106, 128, 227, Gerhardt, Leibniz, philos. Schrift. 3, 166, 174. Schaarschmidt 
states that such dictionaries as Leibnitz here mentions on the authority of 
Grimaldi exist in fact among the Chinese, and have been brought to Europe, 
that the Bonn University library possesses a couple of parts of one such 
dictionary, and that it must be regarded as an alphabetically arranged orbis 
pictus. — Tr. 



ch. xi] ON HUMAN UNDERSTANDING 395 

Society at Pekin, tells me that the Chinese have illustrated 
dictionaries. There is a small nomenclator printed at Nurem- 
berg in which there are such figures for each word which are 
good enough. Such an illustrated universal dictionary were to. 
be desired, and would not be very difficult to make. As for the 
description of species, it is properly natural history, and we 
are working at it by degrees. Were it not for the wars 
(which have troubled Europe since the first foundation of the 
Societies or Royal Academies) it would be farther advanced, 
and already in a condition to profit from our labors ; but the 
great for the most part do not recognize its importance, nor 
what good they deprive themselves of by neglecting the ad- 
vancement of solid knowledge ; and besides they are ordinarily 
too much indisposed -by the pleasures of peace or by the cares 
of war to weigh things which do not strike them at once. 



ESSAY ON UNDERSTANDING 

Book IV. — Of Knowledge 
CHAPTER I 

OF KNOWLEDGE IN GENERAL 

§ 1. Ph. Hitherto we have spoken of ideas and of words 
which represent them ; let us come now to the knowledge, 
which jthe ideas furnish, for it rests only upon our ideas. 
§ 2. Knoivledge is simply the perception of the connection 
and agreement, or of the opposition and disagreement, which 
we find between two of our ideas. Whether we imagine, con- 
jecture, or believe, it is always that. We perceive, for exam- 
ple, by this means, that white is not black, and that the 
angles of a triangle and their equality to two right angles 
have a necessary connection. 

Th. Knowledge has a still more general signification, so 
that we find it also in ideas or terms, before we reach proposi- 
tions or truths. And it may be said that he who has atten- 
tively looked at more pictures of plants and animals, more 
diagrams of machines, more descriptions or representations of 
houses or fortresses, who has read more ingenious romances, 
heard more curious narratives, this one, I say, will have more 
knowledge than another, even though there should not be a 
word of truth in all that which was portrayed or related to 
him ; for the custom he has of representing in his mind many 
express and actual conceptions or ideas, renders him more fit 
to conceive what is placed before him ; and it is certain that 
he will be better instructed and more capable than another 
who has neither seen nor read nor heard anything, provided 

397 



398 LEIBNITZ'S CRITIQUE OF LOCKE [mc. iv 

that in these stories and representations he takes nothing as 
true which is not so and that these impressions do not prevent 
him elsewhere from distinguishing the real from the imagi- 
nary, or the existent from the possible. This is why certain 
logicians of the period of the Reformation who were in some 
measure of the party of the Ramists, 1 were not wrong in say- 
ing that the topics or orders of invention (argumenta, as they 
call them) serve as much for the explication or very detailed 
description of an incomplex theme, i.e. of a thing or idea, as 
for the proof of a complex theme, i.e. of a thesis, proposition, or 
truth. And indeed a thesis may be explained, in order that 
its sense and force may be well known, without raising the 
question of its truth or proof, as is seen in sermons and homi- 
lies explaining certain passages of Holy Scripture, or in 
instruction or lectures upon certain texts of civil or canon law 
whose truth is presupposed. We can even say that there are 
some themes which are means between an idea and a proposi- 
tion. These are the questions, some of which demand only yes 
or no; and they are the nearest to propositions. But there 
are some also which demand the how, the circumstances, etc., 
where there is more to be supplied in order to make proposi- 
tions. It is true, it may be said, that in descriptions 2 (even of 
things purely ideal) there is a tacit affirmation of possibility. 
But it is also true that, as we may undertake the explanation 
and proof of a falsehood, a method which sometimes serves as 
its best refutation, the art of description may fall upon the 
impossible also. Something like this is found in the novelle 
of the Count of Scandiano followed by Ariosto, 3 and in the 

1 The Ramists were disciples of Peter Ramus (cf. infra p. 408, note 1) . 
Schaarschmidt states that Leibnitz probably has in mind chiefly J. H. Alsted, 
whom he has previously (cf. ante, pp. 311, note 2, 362) cited, and whom he 
greatly prized and studied, in whose Sy sterna logicse harmonicum, Her- 
borniae, 1614, p. 69, the argumentum is divided into argumentum simplex 
(which Leibnitz calls them.e incomplexe) and into argumentum complexum. 
The former, according to Alsted, is a "terminus extra omnem dispositionem 
dirigens materiam " (Leibnitz says: "une chose ou idee"), the latter is a 
" definitio et distributio " (Leibnitz says : " une these, proposition ou verite ") . 
Cf. Alsted, p. 261. — Tr. 

2 I.e. in the sense of nominal definitions, which allow the really impossible. 
Cf. ante, p. 317, note 3. — Tr. 

3 Leibnitz here refers to Matteo Maria Boiardo, c. 1434-1494, Count of 
Scandiano, and the author of Orlando Innamorato, which a recent writer 
calls "the most chivalrous poem of the Renaissance," and "a masterpiece of 



ch. i] ON HUMAN UNDERSTANDING 399 

"Aniadis of Gaul " * or other old romances, in the fairy-stories 
which were again in fashion some years since, in the "True 
History" 2 of Lucian and in the "Voyages" of Cyrano de 
Bergerac; 3 to say nothing of the grotesque figures of the 
painters. ^So we know stories with the rhetoricians belong in 
the number of progymnasmata or preliminary exercises. But 
taking knowledge in a narrower sense, i.e. as knowledge of 

inventive genius," and which furnished Ludovico Ariosto, 1474-1533, with the 
theme of his Orlando Furioso. For an account of the two writers and their 
works, cf. J. A. Symonds, Renaissance in Italy, Pt. IV., Italian Literature, 
Vol. 1, pp. 456 sq., Vol. 2, pp. 1 sq. New York, H. Holt & Co., 1885. 

Through a misunderstanding of Leibnitz's reference to the Count of Scan- 
diano, Schaarschmidt, in his note to the passage, has wrongly identified him 
with Tito Giovanni Ganzarini, 1518-1582, Professor of Literature at Modena, 
called il Scandianese, from his birthplace, Scaudiano. Ariosto published his 
Orlando Furioso in 1516, two years before Ganzarini was born, and could 
scarcely be said to have "followed " an author who was only fifteen years 
old when the poet himself died. — Tr. 

1 The Amadis de Gaula, the best of all the old romances of chivalry, was 
originally written, it is supposed, about 1390, by Vasco de Lobeira, a Portu- 
guese knight attached to the court of John I. of Portugal, and who died in 1403. 
The oldest text now extant is in Spanish prose, a version from the Portuguese 
original, now lost, made by Garcia Ordonez de Montalvo, between 1492 and 
1504. Editions of the Spanish version are numerous, the earliest accessible 
being that of 1519 ; and there are translations in English, French, German, 
Italian, and other languages. The best and at present the only readable 
edition in English is the abridged translation (with a Preface giving an 
account, not, however, without error, of the work), made from the Spanish, 
by Robert Southey, London, 1803, 4 vols., 12mo, new ed., London, 1872, 3 vols., 
16mo. Cf. also, V. de Lobeira, Amadis de Gaula, Barcelona, 1847-8, 4 vols., 
16mo; George Ticknor, Hist, of Spanish Lit., 3d ed., Boston, 1863, Vol. 1, 
pp. 198-207; L. Braunfels, Kritischer Versuch uber Amadis, Leipzig, 1876. 
It may be added that the writer of the article, "Amadis of Gaul," in the 
Encyclop. Brit., 9th ed., argues for the Anglo-Norman origin of the romance, 
on the ground that all its ideas and materials, its design and machinery, 
belong to the Anglo-Norman romance-cycle in vogue before Lobeira was 
born. — Te. 

2 The 'A\ijfloOs iaropi'a? koyos (Verse Historise) of Lucian is one of the witty 
satirist's cleverest works, written in easy and elegant Greek, and exhibiting 
great fertility of invention. It was purposely composed, says Lucian, as a 
satire on the poets and logographers who have written so many marvellous 
tales, and contains things which neither he nor any one else has ever seen, 
which not only do not, but cannot, exist, and descriptions of experiences and 
adventures which are absurd and impossible, chief among which is a voyage 
to the moon. Lucian himself says that the only true statement in his History 
is that it contains nothing but lies from beginning to end. It has without doubt 
supplied hints to, or served as a model for, writers like Rabelais, Swift, and 
Cyrano de Bergerac. — Tr. 

3 Cf. ante, p. 228, note 2. Amid many imaginative extravagances, these 
Voyages contain a pretty exact knowledge of the philosophy of Descartes. — Tr. 



400 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

truth, as you, sir, do here, I say it is quite true that truth is 
always grounded in the agreement or disagreement of ideas, 
but it is not true in general that our knowledge of truth is a 
perception of this agreement or disagreement. For when we 
know truth only empirically, from having experienced it, 
without knowing the connection of things and the reason 
there is in what we have experienced, we have no perception 
of this agreement or disagreement, unless we mean that we 
feel it in a confused way without being conscious of it. But 
your examples, it seems, show that you always demand a knowl- 
edge in which one is conscious of connection or opposition, 
and this is what cannot be granted you. Further, we can 
treat a complex theme not alone by seeking the proofs of its 
truth, but also in explicating and otherwise illustrating it, 
according to the topical order, as I have already observed. 
Finally, I have a further remark to make upon our definition : 
viz. that it appears only suited to categorical truths, in which 
there are two ideas, the subject and the predicate ; but there 
is besides a knowledge of hypothetical truths or what may be 
reduced thereto (as disjunctives and others) in which there is 
connection between the antecedent and the consequent propo- 
sition ; thus more than two ideas may enter therein. 

§ 3. Ph. [Let us limit ourselves here to the knowledge of 
truth and then apply what will be said of the connection of 
ideas to the connection of propositions, in order to include in 
one whole the categorical and hypothetical truths.] Now I 
believe that this agreement or disagreement may be reduced 
to four kinds: (1) Identity or diversity, (2) Relation, (3) Co- 
existence or necessary connection, (4) Real existence. § 4. 
For the mind perceives immediately that one idea is not an- 
other, that white is not black ; § 5. then it perceives their 
relation by comparing them with each other; for example, 
that two triangles whose bases are equal and which are found 
between two parallels are equal. § 6. Next there is coexist- 
ence (or rather connection), as fixedness always accompanies 
the other ideas of gold. § 7. Finally there is real exist- 
ence beyond the mind, as when it is said : God is. 

Th. I believe it may be said that the connection is nothing 
else than the agreement or the relation taken generally. And I 
have remarked above that every relation is either of com- 



ch. i] ON HUMAN UNDEESTANDING 401 

parison or concurrence. That of comparison gives diversity 
and identity, either complete or partial ; whereby are consti- 
tuted the concepts of the same or the diverse, the like or unlike. 
Concurrence contains what you call coexistence, i.e. connection 
of existence. But when we say that a thing exists or that it 
has real existence, this existence itself is the predicate, i.e. 
it has a notion joined with the idea in question, and there is 
connection between these two notions. The existence of the 
object of an idea may also be conceived, as the concurrence of 
this object with the Ego. Thus I believe it may be said that 
there is only comparison or concurrence ; but that the com- 
parison which marks identity or diversity, and the concurrence 
of the thing with the Ego, are the relations which deserve to 
be distinguished among others. 1 More exact and more pro- 
found researches might perhaps be made ; but I content myself 
here with making remarks. 

§ 8. Ph. There is actual knowledge, which is the present 
perception of the relation of ideas ; and there is habitual 
knoivledge, when the mind has so evidently perceived the 
agreement or disagreement of ideas, and so placed it in its 
memory, that every time it comes to reflect upon the proposi- 
tion, it is at once certain of the truth it contains without the 
least doubt. For being capable of thinking clearly and dis- 
tinctly of but one thing at once, men would all be very igno- 
rant if they knew only the actual object of their thoughts ; 
and he who knew most would know but one truth. 

Th. It is true that our science, the most demonstrative in- 
deed, being very often obliged to acquire its existence by a 
long chain of inferences, must involve the memory of a past 
demonstration which is no longer distinctly in view, when the 
conclusion is made ; otherwise it would always be repeating 
this demonstration. And even while it lasts it cannot be 
understood as a complete whole at once ; for all its parts can- 
not be present in the mind at the same time ; thus always re- 
calling the preceding part to mind, we should never advance to 
the last which achieves the conclusion. This is the reason also 

1 Leibnitz reduces Locke's four kinds of agreement or disagreement to two, 
and thus generalizes the relation and considers the existence as the concur- 
rence of the object with the Ego. This concurrence Leibnitz explains by his 
doctrine of pre-established harmony. — Tr. 
2d 



402 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

that without writing it would, be difficult properly to establish 
the sciences, the memory not being sufficiently reliable. But 
having put in writing a long demonstration, like, for example, 
those of Apollonius, 1 and having gone over again all its parts, 
as if they were examining a chain, link by link, men can 
assure themselves regarding their reasonings ; for which pur- 
pose proofs are also of use, and the result at last justifies the 
whole. But we see by this that as all belief consists in the 
memory of past life, of proofs or reasons, it is not within our 
power or choice to believe or disbelieve, since memory is not 
a thing depending on our will. 

§ 9. Ph. It is true that our habitual knowledge is of two 
sorts or degrees. Sometimes, truths laid up as it were in the 
memory no sooner present themselves to the mind, than it sees 
the relation between the ideas entering therein ; but, some- 
times, the mind contents itself with the memory of the convic- 
tion, without retaining the proofs, and often, indeed, without 
the power to recall them if it wished. It may be thought that 
this is rather to believe one's memory than really to know the 
truth in question, and this formerly appeared to me to be a 
mean between opinion and knowledge, a kind of assurance 
superior to simple belief based upon the testimony of another. 
But upon clue reflection I find that this knowledge contains 
perfect certainty. I remember, i.e. I know (memory being 
only the reviving of something past), that I was once certain 
of the truth of this proposition, that the three angles of a tri- 
angle are equal to two right angles. Now, the immutability 
of the same relations between the same immutable things 
is at present the mediate idea which shows me that, if they 
were once equal, they will be so still. It is upon this ground 
that in mathematics particular demonstrations furnish general 
knowledge ; otherwise a geometer's knowledge would not ex- 
tend beyond this particular figure which he had drawn while 
demonstrating it. 

Th. The mediate idea of which you, sir, speak, presupposes 
the fidelity of our memory ; but it sometimes happens that our 
memory deceives us, and that we have not made every neces- 
sary effort, although we now believe we have. This is clearly 
seen in the examination of accounts. Sometimes there are 

i Of. ante, p. 108, note 1. — Tr. 



cir. i] ON HUMAN UNDERSTANDING 403 

examiners officially appointed, as at our mines in the Harz, 
and to make the receivers of the particular mines more atten- 
tive, they have imposed a money penalty upon every error in 
calculation ; nevertheless they find them in spite of this pen- 
alty. But the more care we employ, the more reliance we can 
place upon past reasonings. I have devised a method of keep- 
ing accounts, by which he who collects the sums of the col- 
umns leaves upon the paper traces of the progress of his 
reasoning, so that he does not reason in vain. He can always 
revise and correct the last errors without affecting the first : 
the examination, also, which another desires to make costs, in 
this way, almost no trouble, because he can examine the very 
same traces at a glance. There are, besides, means of verifying 
the accounts of each article, by a very convenient kind of proof, 
without increasing to any considerable extent the labor of the 
computation. And all this easily shows that men may have 
rigorous demonstrations on paper, and have an infinite number 
of them. But unless we remember that we have been abso- 
lutely accurate, we cannot have this certainty in the mind. 
And this accuracy consists in an orderly procedure, the observ- 
ance of which in each part is an assurance as regards the 
whole ; as in the examination of a chain by links, in which 
inspecting each to see if it is strong, and measuring with the 
hand so as not to skip any, assurance is obtained of the good 
quality of the chain. And by this means we have all the 
certitude of which human things are capable. But I do not 
agree that in mathematics particular demonstratioyis upon the 
figure which is drawn furnish this general certitude, as you 
seem to take it. For you must know that it is not the figures 
which furnish the proof with geometers, although the style of 
the exposition may make you think so. The force of the dem- 
onstration is independent of the figure drawn, which is drawn 
only to facilitate the knowledge of our meaning, and to fix the 
attention; it is the universal propositions, i.e. the definitions, 
axioms, and theorems already demonstrated, which make the 
reasoning, and which would sustain it though the figure were 
not there. Hence it is that a learned geometer, like Scheube- 
lius, 1 has given Euclid's figures without the letters which might 

1 Johann Scheybl — Latin, Scheubelius — 1494-1570, was, according to Jocher, 
Allgemeines Gelehrten-Lexicon, Leipzig, 1750-51, Vol. 4, p. 257, a professor 



LEIBNITZ'S CRITIQUE OF LOCKE [bk, 



bind them to the demonstration he has put with them ; and 
another, like Herlinus, 1 has reduced the same demonstrations 
to syllogisms and prosyllogisms. 



CHAPTER II 

OF THE DEGREES OF OUR KNOWLEDGE 

§ 1. Ph. Knowledge is then intuitive when the mind per- 
ceives the agreement of two ideas immediately by themselves 
without the intervention of any other. In this case, the mind 
takes no pains to prove or examine the truth. As the eye 
sees the light, the mind sees that white is not black, that a 
circle is not a triangle, that three is two and one. This knowl- 
edge is the clearest and most certain of which human weak- 
ness is capable ; it acts in an irresistible manner without 
allowing the mind to hesitate. It is knowledge that the idea 
is in the mind as perceived. Whoever asks for greater certi- 
tude, knows not what he asks. 

Th. Primitive truths, which are known by intuition, are of 
two kinds, like the derivative. They are truths of reason or 
truths of fact. Truths of reason are necessary, and those 
of fact are contingent. The primitive truths of reason are 
those which I call by the general name of identical, because 
they seem only to repeat the same thing without giving us any 
information. -They are affirmative or negative. The affirma- 
tive are such as the following : Each thing is what it is, and in 

of mathematics in the University at Tubingen. His Euclidis sex libriprimi 
de geometricis principiis gr. et kit. cum commentario appeared at Basle, 1590. 
— Tr. 

1 Christian Herlinus, whom Leibnitz also mentions toward the end of his 
Meditationes de Cog., Verit., et Ideis, as co-editor with Conrad Dasypodius 
(1532-1600, professor of mathematics in Strassburg University, and Canon 
of St. Thomas' Church) of Euclid, appears to be otherwise unknown. Their 
joint work, of which Herlinus did the first and fifth books, and Dasypodius 
the other four, appeared under the title Analysis geometrise sex librorum 
Euclidis, etc., Strassburg, 1566, fol. It is, says Michaucl, Biog. Universelle, 
Vol. 10, p. 560, a pedantic work in which the demonstrations of the Greek 
geometer are reduced to syllogistic form, so that a proposition of fifteen or 
twenty lines is spun out into several pages, and is often more involved or 
at least more difficult to follow. — Tr. 



CH. n] ON HUMAN UNDERSTANDING 405 

as many examples as you please, A is A, B is B. I shall 
be what I shall be. I have written what I have written. And 
nothing in verse as in prose, is to be nothing or a trifle. The 
equilateral rectangle is a rectangle. 1 The rational animal is al- 
ways an animal. And in the hypothetical : If the regular figure 
of four sides is an equilateral rectangle, this figure is a rectangle. 
Copulatives, disjunctives, and other propositions are also sus- 
ceptible of this identicism, and I reckon indeed among the 
affirmatives : non-A is non-A. And this hypothetical: if A is 
non-B, it follows that A is non-B. Again, if non-A is BC, it 
follows that non-A is BC. If a figure having no obtuse angle 
may be a regular triangle, a figure having no obtuse angle may be 
regular. I come now to the identical negatives which belong 
either to the 'principle of contradiction or to the disparates. 
The principle of contradiction is in general : a proposition is 
either true or false: this contains two true statements, one that 
the true and the false are not compatible in one and the same 
proposition, or that a proposition cannot be true and false at 
once ; the other that the opposition or the negation of the true 
and the false are not compatible, or that there is no mean be- 
tween the true and the false, or rather : it is impossible for a 
proposition to be neither true nor false. Now all this is also 
true in all imaginable propositions in particular, as what is A 
cannot be non-A. Again, 2 AB cannot be non-A. An equilat- 
eral rectangle cannot be non-rectangle. Again, it is true that 
every man is an animal, then it is false that any man is found 
who is not an animal. We may vary these statements in many 
ways, and apply them to copulatives, disjunctives, and others. 
As for the disparates, they are the propositions which state 
that the object of one idea is not the object of another idea ; 
as, that heat is not the same thing as color; again, man and 
ayiimal are not the same, although every man is an animal. 
'All this may be asserted independently of all proof or of re- 
duction to opposition, or to the principle of contradiction, 

1 Erdmann and Jacques omit: "Est un rectangle. L'animal raisonnable 
est toujours un animal. Et dans les hypothetiques : Si la figure reguliere de 
quatre costes est un rectangle equilateral." — Tr. 

2 Erdmann and Jacques omit: "Item AB ne sauroit estre non-A. Un 
rectangle equilateral ne sauroit estre non-rectangle. Item il est vray que tout 
homme est un animal, done il est faux," and instead of the last four words, 
read : " Item il est vray," etc. — Tr. 



406 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

when these ideas are sufficiently understood not to require 
here analysis ; otherwise they are liable to be misunderstood : 
for in saying, the triangle and the trilateral are not the same, we 
should be mistaken, since upon proper consideration we find 
that three sides and three angles always go together. In say- 
ing, the quadrilateral rectangle and the rectangle armnot the same, 
we should also be mistaken. For it is found that the four- 
sided figure alone can have all the angles right angles. But 
we may also say in the abstract that the triangle is not the tri- 
lateral, or that the formal causes of the triangle and of the tri- 
lateral are not the same, as the philosophers express it. They 
are different relations of one and the same thing. 

Some one after having heard with patience what we have 
just said up to this point, will lose it after all and will say 
that we are amusing ourselves with frivolous statements, and 
that all identical truths are useless. But he will make this 
judgment for want of having thought sufficiently upon these 
matters. The deductions of logic, for example, are demon- 
strated by identical principles ; and geometers require the 
principle of contradiction in their demonstrations which re- 
duce to the impossible. 1 Let us be content here to show the 
use of identicals in the demonstrations of rational deduction. 
I say, then, that the principle of contradiction alone suffices to 
demonstrate the second and the third figures of the syllogism 
by means of the first. For example, we may conclude in the 
first figure, in Barbara : 

All B is C, 

All A is B, 
Then All A is C. 

Suppose that the conclusion is false (or that it is true that 
some A is not C), then one or the other of the premises will 
be false also. Suppose that the second is true, the first must 
then be false, which maintains that all B is C. Then its con- 
tradictory will be true, i.e. some B will not be C. And this 
will be the conclusion of a new argument, drawn from the 

1 I.e. the so-called indirect proof, which provisionally assumes the truth of 
the contradictory opposite of the proposition to be proved, and then, having 
discovered the impossibility of this assumption, concludes, by the aid of the 
principle of contradiction, that the original proposition is correct. — Tr. 



en. n] ON HUMAN UNDEESTANDING 407 

falsity of the conclusion and the truth of one of the premises 
of the preceding argument. Here is this new argument : 

Some A is not C. 
This is opposed to the preceding conclusion supposed false. 

All A is B. 
This is the preceding premise supposed true. 

Then some B is not C. 

This is the present true conclusion, opposed to the preced- 
ing false premise. 

This argument is in the mode Disamis of the third figure, 
which is thus plainly demonstrated and at once from the 
mode Barbara of the first figure by employing simply the prin- 
ciple of contradiction. And I noticed in my youth, when I 
examined minutely these things, that all the modes of the 
second and third figure may be drawn from the first by this 
method alone, by supposing that the mode of the first is valid, 
and consequently that the conclusion being false, or its contra- 
dictory being taken as true, and one of the premises being 
taken as true also, the contradictory of the other premise is 
true. - It is true that in the schools of logic they prefer to 
make use of conversions to draw the less principal figures from 
the first which is the principal, because this method appears 
better suited to the scholars. But for those who seek demon- 
strative reasons, in which the least possible suppositions must 
be employed, we shall not demonstrate by the supposition of 
conversion what may be demonstrated by the primitive princi- 
ple alone, which is that of contradiction and which assumes 
nothing. I have also made this apparently remarkable obser- 
vation, that only the less principal figures which are called 
direct, viz. the second and the third, can be demonstrated by 
the principle of contradiction by itself : but the less original 
indirect figure, the fourth, whose invention the Arabs attribute 
to Galen, 1 although we found nothing concerning it in the 

1 Claudius Galenns, c. 130-c. 201, a very celebrated physician and medical 
writer, who also wrote a large number of philosophical and logical works, the 
greater part of which are now lost. His medical and scientific treatises contain 
considerable philosophical and logical discussion, and his De usu partium 



408 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

works of his remaining to us, nor in the other Greek authors, 
the fourth, I say, has this disadvantage, that it cannot be 
derived from the first or principal figure by this method 
alone, and it is necessary besides to employ another supposi- 
tion, viz. conversions, so that it is farther removed by one 
degree than the second and the third, which are on a level 
and equally removed from the first ; while the fourth needs 
also the second and the third for its demonstration. <For it is 
found very opportunely that the conversions required are 
demonstrated by the second or third figure, demonstrable 
independently of the conversions, as I have just shown. It is 
Peter Ramus 1 who already made this remark concerning the 
demonstrability of conversion by these figures ; and (if I am 
not mistaken) he reproached the logicians, who make use of 
conversion to demonstrate these figures, with arguing in a 
circle, although it was not so much the circle that he found it 
necessary to reproach them with (for they did not use these 

corp. hum. is, says Janet, " an apology for and a continual application of the 
principle of final causes." The most complete ed. of his works contaiuing 
the Greek text and a Latin version is the Opera Omnia, cur. C. G. Kiihn, 
Leipzig, 1821-33, 20 vols., 8vo. For his philosophical views, cf. K. Sprengel, 
Beitr. z. Gesch. d. Medicin, 1, 117-195, Halle, 1794-6 ; on his logic, cf. Prantl, 
Gesch. d. Logik, 1, 559-577. A brief account of his philosophy is given by 
Zeller, Philos. d. Griech., III., 1 [Vol. 5], 823 sq., 3d ed., Leipzig, 1880. 

The invention of the fourth syllogistic figure was ascribed to Galen by 
Averroes, 1105-1198, but without adequate foundation. Galen was led through 
the additions to the first figure already made by Theophrastus, c. 373-c. 288 
B.C., to transpose the premises in the same, and only by this means indirectly 
to the fourth arrangement of the middle term. Cf. Prantl, Gesch. d. Logik 
im Abendlande, 1, 570-574 ; also Sir W. Hamilton, Lects. on Logic, Boston, 1873, 
Lect. XX., IT LXXIIL, pp. 285-6; Lect. XXL, If LXXIV., p. 302-3, and notes. 
— Tr. 

1 Petrus Ramus — Pierre de la Ramee — 1515-1572, murdered during St. 
Bartholomew's Night, was a determined opponent of Aristotelian scholasticism, 
and especially of its logic or dialectic, in the place of which he attempted to 
set up a new, simpler, and better grounded dialectic. For this purpose he 
wrote and published his two works, Animadversiones Aristotelicse, Paris, 
1534, etc., and Institutiones dialectics, Paris, 1543. Following Cicero and 
Quintilian, his scheme was a blending of logic and rhetoric. For a long time 
after him, logicians were divided into Ramists and Anti-Ramists, while the 
Semi-Ramists, among whom were Alsted and Goclen (cf. ante, p. 311, note 2), 
sought to mediate between the Aristotelic dialectic, as set forth by Melanch- 
thon, and that of Ramus. The remarks to which Leibnitz here refers are 
found, according to Schaarschmidt, in Animad. Aristotel., Lutetise, 1548, 
pp. 388 sq. For a good account of Ramus, cf. Stockl, Gesch. d. Philos. d. 
Mittelalters, III. [Vol. 4], pp. 296 sq.; also Ueberweg-Heinze, Gesch. d. Philos., 
7th ed., 3, 24, 26. — Tr. 



en. n] ON HUMAN UNDEKSTANDING 409 

figures in their turn to justify the conversions) as the hysteron 
proteron or the reversal (le rebours) ; because conversions need 
rather to be demonstrated by these figures, than these figures 
by the conversions. But as this demonstration of conversions 
shows also the use of the identical affirmatives, which many 
take as altogether frivolous, it will be so much more to the 
purpose to introduce them here. I wish to speak only of con- 
versions without contraposition, which suffice me here, and 
which are simple or per accidens, as they are called. Simple 
conversions are of two kinds : that of the universal negative, 
as : no square is obtuse-angled, then no obtuse-angled figure is a 
square ; and that of the particular affirmative, as : some tri- 
angles are obtuse-angled, then some obtuse-angled figures are 
triangles. But conversion per accidens, as it is called, concerns 
the universal affirmative, as : every square is a rectangle, then 
some rectangles are squares. A rectangle is here always under- 
stood to be a figure all of whose angles are right angles, and 
by the square is understood a regular quadrilateral. Now the 
question is to demonstrate these three kinds of conversion, 
which are : 

(1) No A is B, then no B is A. 

(2) Some A is B, then some B is A. 

(3) All A is B, then some B is A. 

Demonstration of the first conversion in Cesare, which 
belongs to the second figure. 

No A is B. 

All B is B. 

Then no B is A. 

Demonstration of the second conversion in Datisi, which be- 
longs to the third figure. 

All A is A. 

Some A is B. 

Then some B is A. 

Demonstration of the third conversion in Darapti, which 
belongs to the third figure. 

All A is A. 

All A is B. 

Then some B is A. 



410 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

This shows that the purest and apparently most useless 
identical propositions are of considerable use in the abstract 
and general; and that may teach us that we should not 
despise any truth. As for this proposition, that three is as 
much as two and one, which you, sir, still adduce as an example 
of intuitive knowledge, I have to say that it is only the defini- 
tion of the term three, for the simplest definitions of numbers 
are formed in this way : Two is one plus one, three is two plus 
one, four is three plus one, etc. It is true that there is therein 
a concealed statement, which I have already spoken of, viz. 
that these ideas are possible : and this is here known intuitively, 
so that it may be said, that an intuitive knowledge is comprised 
in definitions when their possibility appears at once. And in 
this way all adequate definitions contain primitive truths of 
reason and consequently intuitive knowledge. In short, you 
can say in general that all primitive truths of reason are imme- 
diate with respect to an immediateness of ideas. 

As for the primitive truths of fact, they are the immediate in- 
ternal experiences of an immediateness of feeling. And here it 
is that the first truth of the Cartesians or of St. Augustine : I 
think, therefore I am, i.e. I am a thing which thinks, holds good. 1 
But we must know, that as the identicals are general or par- 
ticular, and as one is as clear as the other (since the statement 
that A is A is as clear as the statement that a thing is what it 
is), so is it also with the first truths of fact. For not only is 
it immediately clear to me that / think, but it is wholly as 
clear to me that I have different thoughts, that sometimes / think 
of A, and sometimes of B, etc. Thus the Cartesian principle 
is valid, but it is not the only one of its kind. You see by 
this that all primitive truths of reason or of fact have this 
in common, that they cannot be proved by anything more cer- 
tain. 

§ 2. Ph. I am very glad, sir, that you have carried forward 

1 Cf. Augustine, Solil. II., 1: "Tu qui scis te nosse, scis te esse? Scio! 
Undescis? Nescio! Simplicem te sentis an multipliceni? Nescio! Cogitare 
te scis? Scio!" in Opera, Vol. 1, p. 369, Benedictine ed., Paris, Franciscus 
Muguet, 1679; Vol. 1, p. 885, ed. Migne, Paris, 1841. Augustine, 354-430, thus 
anticipated the principle of Descartes, 1596-1650, " Cogito ergo sum," a fact 
unknown however to Descartes, who was not one of the class of reading 
philosophers, until brought to his knowledge by Arnauld, 1612-1694, and 
Mersenne, 1588-1648, in their criticism of his philosophy. — Tr. 



en. ii] ON HUMAN UNDEKSTANDING 411 

farther than I had done that which relates to intuitive knowl- 
edge. Now demonstrative knowledge is only a concatenation of 
intuitive knowledge in all the connections of mediate ideas. 
For often the mind cannot unite, compare, or apply immedi- 
ately the ideas one to the other, and this compels it to make 
use of other ideas (one or more) as means to the discovery of 
the agreement or disagreement it seeks, and this is what we 
call reasoning. As in demonstrating the three angles of a tri- 
angle to be equal to two right angles, it finds some other 
angles which are seen to be equal both to the three angles of 
the triangle and to two right angles. § 3. These intervening 
ideas are called proofs, and the disposition of the mind to dis- 
cover them is called sagacity. § 4. And even when found, 
this knowledge cannot be acquired without pains and atten- 
tion and by more than a single passing view ; for the mind 
must enter upon a progression of ideas, made gradually and 
by degrees, § 5. and there is doubt before the demonstra- 
tion. § 6. It is not so clear as the intuitive knowledge, as 
.the image reflected by several mirrors from one to another 
grows more and more faint with each reflection, and is no 
longer at once so recognizable especially by weak eyes. It is 
the same with knowledge produced by a long train of proof. 
§ 7. And although each step taken by reason in the demon- 
stration is intuitive knowledge or simple sight, nevertheless 
as in this long train of proofs the memory does not so exactly 
preserve this connection of ideas, men often take fallacies for 
demonstrations. 

Th. Besides natural sagacity or that acquired by exercise, 
there is an art of finding mediate ideas (the medium), and this 
art is analysis. Now it is well to consider- here, that the ques- 
tion is sometimes to find the truth or falsehood of a given 
proposition, which is nothing else than an answer to the ques- 
tion An? i.e. whether it is or is not. Sometimes it concerns 
an answer to a more difficult (cceteris paribus) question, where 
it is asked for example by whom and how ? and where there is 
more to be supplied. And it is these questions alone, which 
leave a part of the proposition blank, which the mathemati- 
cians call problems. As, when we are asked to find a mirror 
which collects all the rays of the sun in one point, we are 
asked for its form, or how it is made. As for the first ques- 



412 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

tions in which the point at stake is only truth and falsehood 
and where there is nothing to be supplied in the subject or 
predicate, there is less invention, yet there is some, and the 
judgment alone is not sufficient. It is true that a man of judg- 
ment, i.e. one who is capable of attention and reserve, and 
who has the leisure, the patience, and the necessary freedom 
of mind, may understand the most difficult demonstration if 
properly set before him. But the most judicious man in the 
world, without other aid, will not always be capable of discov- 
ering this demonstration. Thus there is still some invention 
therein ; and with geometers there was more of it formerly 
than now. For when analysis was less cultivated, more sagac- 
ity was necessary to attain it, and it is on this account that 
some geometers still of the old school, 1 or others who have not 
yet sufficient aptness in the new methods, think they have 
done something wonderful when they discover the demonstra- 
tion of some theorem that others have invented. But those 
who are versed in the art of invention know when this is esti- 
mable or not ; for example, if some one sets forth the quadra- . 
ture of a space comprised within a curved and a straight line, 
which is successful in all its segments and which I call general, 
it is always within our power according to our methods to dis- 
cover its demonstration, provided we are willing to take the 
trouble. But there are some particular quadratures of certain 
portions, where the thing may be so involved, that it will not 
always be possible (in potestate) thus far to develop it. It 
happens also that induction presents us with truths in num- 
bers and in figures whose general reason is not yet discovered. 
For much is needed in order to attain perfection of analysis in 
geometry and in numbers, as many are becoming conceited 
upon the basis of the boasts of some men otherwise excellent, 
but a little too hasty or too ambitious. 

But it is much more difficult to discover important truths, 
and still more to discover means of producing what is sought, 
when it is justly sought, than to discover the demonstration 
of truths which another has discovered. Beautiful truths are 
often attained by synthesis, by passing from the simple to the 
complex ; but when it is a question of discovering exactly the 
means of producing what is proposed, synthesis is ordinarily 

l Gerhardt reads ; " roche " ; Erdmaim and Jacques : " race." — Tr. 



ch. ii] ON HUMAN UNDERSTANDING 413 

not sufficient, and often to be willing to make all the requisite 
combinations would be an endless task, although one might 
often be aided therein by the method of exclusion, 1 ^which cuts 
off a good portion of useless combinations, and often nature 
does not admit any other method. But the means are not al- 
ways at hand for the proper pursuit of this method. Analysis 
then must give us a thread in this labyrinth, when it is possi- 
ble, for there are cases where the nature itself of the question 
demands that we grope about, short cuts not being always 
possible. 

§ 8. Ph. Now as in demonstration intuitive knowledge is 
always supposed, it has, I think, given occasion for this maxim : 
that all reasoning springs from things already known and agreed 
to (ex pruicognitis et prceconcessis) . 2 But we shall have occasion 
to speak of the falsity of this axiom when we speak of the 
maxims which are improperly taken as the foundation of our 
reasoning. 

Th. I am curious to learn what falsehood you can find in an 
axiom apparently so reasonable. If it were always necessary 
to reduce everything to intuitive knowledge, demonstration 
would often be insufferably prolix. This is why mathema- 
ticians have had the cleverness to divide the difficulties and to 
demonstrate separately the intervening propositions. And 
there is art also in this ; for as the mediate truths (which are 
called lemmas, since they appear to be a digression) may be 
assigned in many ways, it is well, in order to aid the under- 
standing and the memory, to choose those of them which 
greatly shorten the process, and appear memorable and worthy 
in themselves of being demonstrated. But there is another 

1 The "method of exclusion " or elimination, says Schaarschmidt, proceeds 
from a disjunctive judgment, the predicate of which embraces in the sum of 
its divisional members all possible determinations of the subject. After it has 
been shown that individual divisional members cannot be united with the 
subject in a categorical judgment, that one alone of the divisional members 
which cannot be separated from the subject remains as the actual predicate 
for the valid determination of the subject. For example: A is B, or C, or D, 
or E. In this formula, B, C, D, E must include all thinkable predicate- 
determinations of A. In the question: Is A, B, or C, or D, or E, it is then 
proved that A is not C, D, E, in which case A must be B; or that A is not 
B, D, E, in which case A must be C, and so on. — Tr. 

2 Cf. Aristotle, Analyt. Post., I., 1, p. 71\ 1: natra SiSa<TKa\ia Ka\ na,<ra i*a0r)o-i$ 
BiauorjTiKyj e/c 7rpov7rapxova"q9 ytVerat ■yytocrecos. — TR. 



414 LEIBNITZ'S CRITIQUE OF LOCKE [be. iv 

obstacle, viz. : that it is not easy to demonstrate all the axioms, 
and to reduce demonstration wholly to intuitive knowledge. 
And if we had chosen to wait for that, perhaps we should not 
yet have the science of geometry. But we have already spoken 
of this in our former conversations, and we shall have occasion 
to speak of it again. 

§ 9. Ph. We shall come to that presently ; now I shall re- 
mark again what I have already touched upon more than once, 
that it is a common opinion that only the mathematical 
sciences are capable of a demonstrative certainty ; but as the 
agreement and disagreement which may be known intuitively 
is not a privilege belonging only to the ideas of numbers and 
figures, it is perhaps for want of application on our part that 
mathematics alone have attained to demonstrations. § 10. 
Many reasons conspired to this end. The mathematical 
sciences are very generally useful ; the least difference therein 
is very easily recognized. § ll. 1 These other simple ideas, 
which are appearances or situations produced in us, have no 
exact measure of their different degrees. § 12. 2 But when the 
difference of these visible qualities, for example, is sufficiently 
great to excite in the mind clearly distinct ideas, as those of 
blue or red, they are as capable of demonstration as those of 
number and extension. 

Th. There are notable examples enough of demonstration 
outside of mathematics, and it may be said that Aristotle has 
already given some in his " Prior Analytics." In fact logic is 
as susceptible of demonstrations as geometry, and it may be 
said that the logic of the geometers, or the methods of argu- 
mentation explained and established by Euclid in reasoning 
upon propositions, are a particular extension or promotion of 
general logic. Archimedes 3 is the first, whose works we have, 
who has practised the art of demonstration upon an occasion 
where he is treating of physics, as he has done in his book on 

1 § 11, as also § 12, is § 17 in the texts of Erdmann and Jacques. — Tr. 

2 § 12 is § 13 in Locke, Philos. Works, Vol. 2, p. 140 (Bonn's ed.). — Tr. 

3 Archimedes, 287-212 B.C., the greatest mathematician among the Greeks, 
distinguished also for his discoveries in hydrostatics and hydraulics, and for 
his ingenious inventions. He first placed the science of engineering upon a 
sound mathematical basis. The most complete and magnificent edition of his 
extant works is that edited by Torelli and published at Oxford, at the Claren- 
don Press, 1792, fol. — Tr. 



cn. n] ON HUMAN UNDERSTANDING 415 

Equilibrium. Furthermore, jurists may be said to have many 
good demonstrations; especially the ancient Roman jurists, 
whose fragments have been preserved to us in the Pandects. 
I am wholly of the opinion of Laurentius Valla, 1 who cannot 
enough admire these authors among others, because they all 
speak in a manner so just and so clear and in fact reason in 
a way closely approaching the demonstrative, and often it is 
wholly demonstrative. 2 Indeed, I do not know any science 
outside that of law and that of arms, in which the Romans 
have made any considerable addition to what they received 
from the Greeks. 

Tu regere imperio populos Roruane memento : 
Hte tibi erunt artes pacique imponere morem, 
Parcere subjectis, et debellare superbos. 3 

This precise manner of expressing themselves is the reason 
that all the jurists of the Pandects, though sometimes quite 

1 Laurentius Valla — Lorenzo della Valle — c. 1407-1457, a humanist and 
philologian of the earlier Italian Renaissance, was an earnest opponent of the 
scholastic dialectic, a determined foe of tradition and authority, and the initi- 
ator and champion of a hold and unbiassed criticism which he applied to 
language, historical documents, and ethical opinions. He was eminent as a 
Latinist, and his treatise Elegantise latinss linguse, c. 1431, in six books, — ■ 
the Preface to the third book of which Schaarschmidt thinks Leibnitz probably 
had in mind in referring to Valla's admiration for the style of the Roman 
jurists, therein very highly praised, — subjected the forms of Latin grammar 
and rhetoric to critical investigation and analysis, and established upon a 
scientific foundation the principles of Latin style. His De /also credita et 
ementita Constantini Donations, 1440, destroyed the claims of the Papacy to 
temporal power based upon this alleged " Donation," by proving its docu- 
mentary foundations to be forgeries. His principal philosophical writings are : 
De voluptate et vero bono, 1131, in which he boldly defended the Epicurean 
doctrine of pleasure as the true and only good; De libero arbitrio ; and the 
Dialectics disputationes contra Aristotelicos, 1499, of which Prantl, Gesch. 
d. Lof/iJc im Abendlande, 4, 161-167, gives some account with citations. 
Valla's Opera Omnia, Basilise, 1465 and 1510-1543. Leibnitz refers to him 
and his De lib. arbit. and De voluptate in the The'odicee, Pt. III., §§ 405 sq. 
For accounts of his life and works, cf. G. Tiraboschi, Storia della Letteratura 
Italiana, Vol. 6, Pt. II., pp. 339-340, Rome, 1784; Symonds, Renaissance in 
Italy, Pt. II., The Revival of Learning, p. 258 sq., New York, H. Holt & Co., 
1881. For his philosophy, cf. Stocki, Gesch. d. Philos. d. Mittelalters, III. 
[Vol. 4] , 279-283. Mancini published at Florence, 1891, a brilliant and exhaus- 
tive monograph investigating and settling disputed points in Valla's life.— Tr. 

2 Cf. Leibnitz's letter to Kestner, No. 15, in Ch. Kortholt, Leibnit. epist. 
ad diversos, Lipsite, 1734-1742, Vol. 3, p. 256, Dutens, Leibnit. opera omnia, 
Vol. 4, Pt. III., p. 267, where he expresses himself similarly as here. Also, 
Guhrauer, Leibniz, eine Biographie, Pt. I., pp. 36, 37. — Tk. 

3 Verg. Mn. 6, 851-853. — Tr. 



416 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

distant from one another in time, seem to be a single author, 
and there would be much difficulty in distinguishing them, if 
the names of the writers were not at the beginning of the ex- 
tracts ; as it would be difficult to distinguish Euclid, 1 Archi- 
medes and Apollonius 2 in reading their demonstrations upon 
matters which the one as well as the other has touched upon. 
It must be admitted that the Greeks have reasoned with all 
possible accuracy in mathematics, and that they have left the 
human race models in the art of demonstration: for if the 
Babylonians and the Egyptians had anything more than an 
empirical geometry, nothing of it at least remains ; but it is 
astonishing that these same Greeks lost it to such an extent 3 
at once as soon as they turned aside ever so little from num- 
bers and figures in order to proceed to philosophy. For it is 
strange that we do not see a shadow of demonstration in Plato 
and in Aristotle (his " Prior Analytics " excepted) and in all 
the other ancient philosophers. Proclus 4 was an excellent 
geometer, but he seems another man when he speaks on phi- 
losophy. What has made it easier to reason demonstrably in 
mathematics is largely the fact that experience can there guar- 
antee the reasoning at every moment, as is also the case in the 
syllogistic figures. But in metaphysics and ethics this par- 
allelism of reason and experience is no longer found; and in 

1 Cf. ante, p. 93, note 1. — Tr. 2 Cf. ante, p. 108, note 1. — Tr. 

3 A strange remark for Leibnitz to make, who had so thoroughly studied 
Aristotle in his youth, and in later years Plato, whose works contain demon- 
strations inferior in no respect certainly to the precision of the Pandects. The 
only explanations that seem to touch the case are that Leibnitz had in mind the 
stringency and completeness of mathematical demonstration, which in form, 
and sometimes in content also, is apparently, and sometimes really, superior, 
though not necessarily so merely because mathematical, to the demonstrations 
of philosophy ; or, as he seems to suggest in the immediately following con- 
text, that metaphysics being a matter of pure thought and ethics largely an 
ideal not as yet realized in the actual, their demonstrations cannot, like those 
of mathematics, be experimentally verified, and must thus be regarded as, in 
a sense, lacking in completeness as demonstrations. — Tr. _ 

4 Cf. ante, p. 108, note 2. Leibnitz's remark concerning Proclus has its 
justification in the fact that his philosophical system, while embracing the 
entire philosophy and theology of his predecessors methodically elaborated 
with great dialectic art and skill, is yet purely formal in its completeness, its 
thought exhibiting little freedom or creative power, and wholly lacking in any 
real scientific basis and character. Though presenting here and there evidence 
of deep speculative ability on the part of its author, his philosophy is never- 
theless wholly wanting in such demonstration as is found in his mathematical 
work. — Tr. 



ch. n] ON HUMAN UNDERSTANDING 417 

physics experiments demand labor and expense. Now men 
at once relaxed their attention, and as a consequence were 
led astray when they were destitute of this faithful guide, 
experience, who aided and sustained them in their walk, as 
that little revolving machine does, which prevents children 
from falling when walking. There was a succedaneum, 1 but it 
is something that has not been and is not yet sufficiently con- 
sidered. And I shall speak of it in its place. For the rest, 
blue and red are scarcely capable of furnishing matter for 
demonstration by means of the ideas we have of them, because 
these ideas are confused. And these colors do not supply 
matter for reasoning so long as in experience they are found 
accompanied by some distinct ideas, but in which the con- 
nection with their own ideas does not appear.] 

§ 14. Ph. Besides intuition and demonstration, which are 
the two degrees of our knowledge, all the rest is faith or 
opinion, and not knowledge, at least as regards all general 
truths. But the mind has also another perception, regarding 
the particular existence of finite beings outside of us, and this 
is sensitive knoivledge. 2 

Th. [Opinion, based on probability, deserves perhaps the 
name knowledge also ; otherwise nearly all historic knowledge 
and many other kinds will fall. But without disputing about 
terms, I hold that the investigation of the degrees of probability 
is very important, that we are still lacking in it, and that this 
lack is a great defect of our logics. 3 For if the question can- 
not always be decided absolutely, the degree of resemblance 
ex datis can always be determined, and consequently one can 
reasonably judge what view is the most likely. And when 

1 I.e., a substitute. The expression was much used by the later Roman 
jurists. — Tr. 

2 Locke's word is " sensitive," Philos.Wks. (Bohn's ed.), Vol. 2, p. 141, aclfln. 
His three degrees of knowledge are intuitive, demonstrative, and sensitive, cf. 
infra, p. 420. — Tr. 

3 Of. Leibnitz's letter to Kestner, No. 11, Jan. 30, 1711, § 3 (Dutens, Leibnit. 
op. om. 4, Pt. III., 264, and Kortholt, Leibnit. epist. ad diversos, 3, 251) : "Ea 
vero pars Logicae, qua sc. gradus verisimilitudinum et argumentorum pondera 
constituerentur, nuspiam hactenus reperitur traditur. Ego juvenis aliquando 
aggressus sum, sed per varia dissipatus, fere intra voluntatem steti. Topica 
Aristotelis scopo meo non respondet. Congerit regulas, quae occasionem 
aliquam praebere possunt de argumentis cogitandi, sed quae non possunt 
docere, quantum cuique argumento ant judicio ponderis insit." — Tr. 

9 T? 



418 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

our moralists (I mean the wisest of them, such as the present 
(moderne) General of the Jesuits) 1 unite the safest and the most 
probable, and prefer even the safe to the probable, 2 they are 
not far in fact from the most probable ; for the question of 
safety is here that of the little probability of an evil to be 
feared. The fault of the moralists lax upon this article 3 has 
largely been, that they have had a too limited and too inade- 
quate notion of the probable, which they have confounded with 
the Endoxon 4 or the probable (opinable) of Aristotle; for Aris- 
totle in his " Topics " did not mean to accommodate himself to 
the opinion of others, as did the orators and sophists. Endoxon 
is with him what has been received from the greatest number 
or the most authoritative : he is wrong in having restricted 
his " Topics " to this, and this view caused him to adhere only 
to received maxims, for the most part vague, as if he wished 

1 Leibnitz probably refers to Tirso Gonzalez, General of tbe Jesuits from 
1687-1705, and author of a. work on probabilism, opposing tbe doctrine and 
maintaining that tbe Jesuits did not originate it, entitled Fundamentum 
theologisB moralis, id est tractatus theologicus de recto usu opinionum proba- 
bilium, 4to, Dillingen, 1689, Naples, 1694. An abridgment with the title Synop- 
sis tract. theol. de recto usu opinionum probab ilium, concinnata a theologo 
quodam Soc.Jesu: cui accessit logistica probabilitatum, 3d ed., appeared at 
Venice, 1696, 8vo. Cf. Michaud, Biog. Univ. 18, 111-112, Du Pin, Biblioth. des 
aut. eccles. du XVII. siecle, and, for the De recto usu opiin. prob., Migne, Theol. 
cur. compl. Vol. 11, p. 1397.— Tr. 

2 The theory of moral probabilism is, perhaps the most celebrated question 
discussed in Moral Theology, and formed one of the chief subjects of contro- 
versy between the Jansenists ' and the Jesuits of the seventeenth century. 
The aim of moral probabilism is to find some rule by which action may be 
determined in that portion of the moral realm in which certainty is impossible, 
and probability only can be attained. The probable opinion being that which 
has a certain number of arguments in its favor, either intrinsic, i.e., grounded 
in reason, judgment in regard to which was restricted to men of considerable 
education and especially to those versed in moral theology, or extrinsic, i.e., 
resting on some external authority, such as that of some theologian of repute ; 
and the safe opinion, that which conforms to the moral law, casuists distinguish 
the following doctrines: 1. Probabilism, which permits action in accord with 
the opinion which is least probable and least safe ; 2. Probabilorism, or the 
preference of the "most probable opinion, regardless of its relative safety; 
3. Tutiorism, or the choice of the safest opinion, without regard to its rela- 
tive probability. On the whole subject, cf. the dissertation of Pierre Nicole 
annexed to his Latin trans, of Pascal's Lettres provinciates, and Janet, La 
Morale, Bk. III., Chap. 3, Paris, 1874, Eng. trans., The Theory of Morals, pp. 
292-308, New York, Chas. Scribner's Sons,' 1883. — Tr. 

3 According to Janet, the casuists refuted by Pascal. — Tr. 

Cf. Topics, I., 1, 100" 21 : eySo^a Se to Sokovvto. naoriv r) tois TrXeiaTOis 17 rot? co^oi?, 
Kai toutois 17 -naaiv r) tois TrAeurToi? ij toi? ^aAicrTa yviopifiois Kai ey6d£tRS. — Tr. 



en. n] ON HUMAN UNDERSTANDING 419 

to reason only by means of quodlibets * or proverbs. But the 
probable or the likely is more extended : it must be drawn 
from the nature of things ; and the opinion of persons whose 
authority has weight is one of the things which may contribute 
to render an opinion probable, but not what completes the en- 
tire verisimilitude. At the time when Copernicus 2 was almost 
alone in his opinion, it was still incomparably more probable 
than that of all the rest of the human race. Now T do not know 
but that the establishment of the art of estimating probabilities 3 
would be more useful than a majority of our demonstrative 
sciences, and I have thought of this more than once.] 

Ph. Sensitive knoivleclge, or that which establishes the exist- 
ence of particular beings without us, goes beyond bare proba- 
bility ; but it has not all the certainty of the two degrees of 
knowledge of which we have just spoken. Nothing is more 
certain than that the idea we receive of an external object is 
in our mind, and this is intuitive knowledge : but the knowl- 
edge whether from this we can certainly infer the existence 
of anything without us corresponding to this idea, this it is 
which certain persons think may be questioned, because men 
may have such ideas in their minds, when no such thing actu- 
ally exists. For myself I believe, however, that there is a 
degree of evidence which elevates us beyond doubt. One is 
unalterably convinced that there is a great difference between 
the perceptions which he has when by day he looks at the sun, 
and when by night he thinks about it ; and the idea which is 

1 The Mediaeval Latin " quodlibetum " was a very elaborate and subtle 
scholastic argumentation upon a question chosen at pleasure — " quod libet" 
— but almost always of a theological or philosophical character. Such ques- 
tions were called " quodlibetariae qusestiones " ; they were proposed chiefly 
for the exercise of students, and their discussion was carried on to satisfy 
curiosity or for entertainment, and, for the most part, served rather to exhibit 
the skill and dexterity of the dialectician than to establish truth. The French 
word "quolibet," starting from the scholastic use of the term in the sense of 
an argumentative subtlety, came by a debasing extension of this meaning to 
signify a witty, but not always appropriate commonplace, a bad joke, a pun, 
an epigram ; and it is in this sense that Leibnitz, coupling the word with 
"proverbs," uses the term. — Tr. 

2 Nicolas Copernicus, 1473-1543, published bis theory of the planetary system 
in his Be oj'bium ccelestium revolutionibus lit. VI., Nuremberg, 1543, 2d ed., 
Basle, 1568, both fol. 3d ed., with notes by Nicolas Muler in his Astronomia 
Instaurata, Amsterdam, 1617 and 1640, 4to. — Tr. 

3 Cf. ante, p. 213, note 2, p. 214, note 1 ; also Erdmann, Leibnit. opera 
philos., 84. — Tr. 



420 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

renewed by recourse to the memory is very different from that 
which actually comes to us by means of the senses. Some one 
will say that a dream may produce the same effect. I reply 
in the first place that it matters little that I remove this doubt, 
because if all is but a dream, reasoning is useless, truth and 
knowledge nothing at all. In the second place, he will ac- 
knowledge, in my opinion, the difference between dreaming of 
being in a fire, and being actually in it. And if he persists in 
appearing sceptical, I shall tell him that it is enough that we 
certainly find pleasure or pain following the application to 
ourselves of certain objects, true or dreamt of, and that this 
certitude is as great as our happiness or misery ; two things 
beyond which we have no interest. Thus I think we may count 
three sorts of knowledge : intuitive, demonstrative and sensitive. 
" Th. [I think you are right, sir, and I also think that to 
these species of certitude or certain knowledge you can add the 
knowledge of the j^'ooable; thus there will be two sorts of 
knowledge, as there are two sorts of proofs, the first of which 
produce certitude, and the second end only in probability. But 
let us come to this dispute of the Sceptics and the Dogmatists 
upon the existence of things without us. We have already 
touched upon it, but we must return to it here. I formerly 
discussed the subject a great deal viva voce and in writing 
with the late Abbe Foucher, 1 Canon of Dijon, a learned and 

1 Simon Foucher, 1644-1696, a devoted student of the Platonic philosophy, 
in consequence of which he was called " the restorer of the philosophy of the 
Academy." His Critique de la Recherche de la Verite, here mentioned hy 
Leibnitz, appeared at Paris, 1675. It was based upon the sceptical principles 
of the Middle Academy, and was subjected to a very sharp criticism by Male- 
branche in the Preface to the next edition of the Recherche de la Verite. 
Foucher also wrote Dissertation sur la recherche de la ve'rite ou sur la philo- 
sophic des acade'miciens, Paris, 1673, said to be his best work, and De la 
Sagesse des anciens, Paris, 1683. For Foucher's " objections " (published in 
the "Journal des Savans " of Sept. 12, 1695) to Leibnitz's doctrine of pre- 
established harmony as set forth in the Systeme nouveau (" Jour, des Savans," 
June 27, 1695), cf. Gerhardt, 1,424, and 4, 487, Erdmann, 129, Dutens, 2, Pt. I., 
102, trans. Duncan, 81; and for Leibnitz's reply ("Jour, des Savans," April 2 
and 9, 1696), cf. G. 4, 493, E. 131, Dutens, 2, Pt. I., 67, trans. Duncan, 85. The 
correspondence of Foucher with Leibnitz was first published by Foucher de 
Careil in his Lettres et opuscules inedits de Leibniz, Paris, 1854, pp. 27-131 (cf. 
Introd. pp. 22-4:1, where the controversy over Malebranche is thoroughly con- 
sidered) , and more recently, 1875, after a new comparison with the originals 
in the Royal Library at Hannover, by Gerhardt, Leibniz, philos. Schrift., 1, 
363 sq. — Tr. 



ch. ii] ON HUMAN UNDERSTANDING 421 

subtile man, but a little too prepossessed in favor of bis Acad- 
emicians, which sect he was very desirous of reviving, as Gas- 
sendi * had brought upon the stage that of Epicurus. 2 " His 
critique upon " The Search after Truth," 3 and the other minor 
treatises which he afterwards published, have made their 
author quite well known. He published also in the " Journal 
des Savans " some objections to my System of Pre-established 
Harmony, when I gave it to the public after having digested 
it for many years ; but death prevented him from replying to 
my answer. He always preached the necessity of guarding 
against prejudice and of using great accuracy, but besides the 
fact that he himself did not make it his duty to carry out his 
counsel to others, in which he was perhaps excusable, it seems 
to me that he was not careful whether another did it, antici- 
pating doubtless that no one would ever do it. Now I showed 
him that the truth of sensible things consisted only in the 
connection of phenomena, which must have its reason and is 
that which distinguishes them from dreams ; but that the 

1 Cf. ante, pp. 64, note 2, 65, n. 3. Gassendi published on the life and phi- 
losophy of Epicurus: De vita, moribus et doctrina Epicuri, Lugcl. Bat., 1647; 
Animadver siones in libr. X. Diog. Laert. de Epicure-, Lugd. Bat. 1649; Syn- 
tagma philos. Epicuri, The Hague, 1655. For his philosophy, cf. his Syntagma 
philosophicum, Vols. 1 and 2 of his Opera omnia; also Stockl, Gesch. d. Phi- 
los. d. Mittelalters, III. [Vol. 4] , 316-327 ; Lange, Gesch. d. Materialismus, 
Vol. 1, Eng. trans. Vol. 1, pp. 253-269; R. Adamson, article "Gassendi," in 
Encyclop. Brit., 9th ed. — Tr. 

2 Cf. ante, p. 126, note 1. On his life and philosophy, cf. Zeller, Philos. d. 
Griech., III., 1 [Vol. 5], 363 sq., 3d ed., Leipzig, 1880; Lange, Gesch. d. Materi- 
alismus, Vol. 1, Eng. trans., Vol. 1, pp. 98 sq. ; Benn, The Greek Philosop)hers, 
Vol. 2, pp. 53 sq. ; Win. Wallace, Epicureanism, in the series of " Chief 
Ancient Philosophies," pub. by the Society for promoting Christian Knowl- 
edge, London, 1880. — Tr. 

3 The De la Recherche de la VeriU, the principal work of Malebranche, 
1638-1715, appeared in 1674-1679. The most recent edition is that of F. Bouil- 
lier, with an introduction and notes, 2 vols., Paris, 1880. On Malebranche's 
philosophy, cf. Bouillier, Histoire de la Philos. Cartesienne, Paris, 1854; Olle'- 
Laprune, La Philos. de Malebranche, 2 vols., Paris, 1870-1872; Kuno Fischer, 
Gesch. d. n. Philos., 3d ed., I., 1, Eng. trans, by J. P. Gordy, New York, Scrib- 
ners, 1887 ; Martineau, Types of Ethical Theory, 2d ed., Vol. 1, p. 159 sq. For 
a critical account of Malebranche's place in the history of philosophy, cf. 
Edward Caird, article " Cartesianism," in Encyclop. Brit., 9th ed. For Leib- 
nitz's correspondence with Malebranche, cf. Gerhardt, Leibniz, philos. Schrift., 
1, 315-361; for his discussion of Malebranche's philosophy, cf. Gerhardt, 3, 
656-660, Erdmann, 735-737, Dutens, 2, Pt. I., 213, trans. Duncan, 233-237; G. 
6, 579-594 {cf. also 48L483), E. 690-697, D. 2, Pt. I., 201 ; G. 6, 574-578 (cf. also 
480-483; Locke's examination of Malebranche is in his Philos. Works, Vol. 2, 
413-458, Bohn's ed.), E. 450-452, trans. Duncan, 185-189. —Tr. 



422 LEIBNITZ'S CEITIQUE OF LOCKE [bk. it 

truth of our existence aud the cause of phenomena is of a 
different nature, because it establishes substances, and that 
the Sceptics spoiled what they rightly say by carrying it too 
far, and by wishing indeed to extend their doubts even to 
immediate experience, and to the geometrical truths, a thing 
which Foucher did not do however, and to the other truths 
'of reason, which he did a little too much. But to return to 
you, sir, you are right in saying that there is ordinarily some 
difference between feelings and imaginations ; but the Sceptics 
will say that the more or less does not alter the species. Be- 
sides, although feelings are wont to be more vivid than im- 
aginations, it is nevertheless a fact that there are cases where 
imaginative persons are impressed as much or perhaps more 
by their imaginations than another is by the truth of things ; 
so that I think the true criterion concerning the objects of the 
senses is the connection of the phenomena, i.e. the connection 
of that which takes place in different places and times, and 
in the experience of different men who are themselves, each to 
the others, very important phenomena in this respect. And 
the connection of the phenomena which guarantees the truths of 
fact in respect to sensible things outside of us, is verified by 
means of the truths cf reason; as the phenomena of optics are 
explained by geometry. It must, however, be admitted that 
none of this certitude is of the highest degree, as you have 
well recognized. For it is not impossible, metaphysically 
speaking, that there may be a dream continuous and lasting 
like the life of a man ; but it is a thing as contrary to reason 
as would be the fiction of a book which should be formed by 
chance by throwing together the type pell-mell. For the rest, 
it is also true that, provided the phenomena are connected, it 
does not matter whether they are called dreams or not, since 
experience shows that we are not deceived in the measures we 
take concerning phenomena when they are understood accord- 
ing to the truths of reason. 1 ] 

1 Cf. New Essays, Bk. III., chap, 1, § 2, Th., ante, pp. 318, 319, notes 1 and 
2, and Bk. IV., chap. 11, § 10, Th., infra, p. 512. The principle of the "con- 
nection of the phenomena," their constant occurrence in the same order and 
relations, giving them a certain measure of objectivity in our consciousness 
and enabling us to predict the appearance of other members of the series when 
one member presents itself, is for Leibnitz the guarantee of the truth of our 
sense-knowledge and the ground of our greatest possible certainty therein; 



oh. in] ON HUMAN UNDERSTANDING 423 

§ 15. Ph. For the rest, knowledge is not always clear, though 
ideas may be. A man who has as clear ideas as any mathe- 
matician in the world of the angles of a triangle and of equality 
to two right angles, may yet have a very obscure perception of 
their agreement. 

Th. [Ordinarily when ideas are thoroughly understood their 
agreements and disagreements appear. I admit, however, that 
at times some of them are so complex, that much care is needed 
to develop what they conceal ; and in this respect certain 
agreements or disagreements may still remain obscure. As 
to your example, I remark that if we have in the imag- 
ination the angles of a triangle we do not on that account 
have clear ideas of them. The imagination cannot furnish us 
an image common to acute-angled and obtuse-angled triangles, 
and yet the idea of triangle is common to them : thus this 
idea does not consist in images and it is not as easy as you 
may think thoroughly to understand the angles of a triangle.] 



CHAPTEE III 

OF THE EXTENT OF HUMAN KNOWLEDGE 

§ 1. Ph. Our knowledge does not extend beyond our ideas, 
§ 2. nor beyond the perception of their agreement or dis- 
agreement. § 3. It cannot always be intuitive, because we 
cannot always compare things immediately, for example, the 
size of two triangles upon one and the same base, equal, but 
very different. § 4. Our knowledge, also, cannot always be 
demonstrative, for we cannot always find mediate ideas. § 5. 
Finally, our sensitive knowledge regards only the existence of 
things which actually strike our senses. § 6. Thus not only 
our ideas are limited, but also our knowledge is more limited 
than our ideas. I do not doubt however that human knowl- 
edge can be carried much farther if men will devote them- 

but he holds that this guarantee is " verified," and the consecutions of experi- 
ence supplemented, "by means of the truths of reason," and particularly by 
the use of the principles of logic. The position here taken is also that of the 
modern scientist, who keeps strictly within the scientific realm and does not 
pass on to consider the ultimate metaphysical nature and ground of the 
phenomena he investigates. — Tr. 



424 LEIBNITZ'S CEITIQUE OE LOCKE [bk. iv 

selves sincerely to discovering the means of perfecting truth, 
with entire freedom of mind and with all the application and 
industry they employ in coloring or maintaining falsehood, in 
defending a system in favor of which they have declared 
themselves, or else a certain party and certain interests, with 
which they find themselves united. But after all our knowledge 
can never embrace all we may wish to know concerning the 
ideas we have. For example, we shall never perhaps be able 
to find a circle equal to a square, and know certainly that it is so. 
I Tk. [There are confused ideas in which we cannot promise 
ourselves a complete knowledge, like those of certain sensible 
qualities. But when they are distinct, there is room to hope 
for all. As for the square equal to the circle, Archimedes has 
already shown that there is one. For it is the one whose side 
is the mean proportional between the semi-diameter and the 
semi-circumference. He has also determined a straight line 
equal to the circumference of the circle by means of a straight 
line tangent to the spiral, as others by the tangent to the 
quadratrix ; a method of quadrature with which Clavius 1 was 
wholly content ; not to speak of a thread applied to the cir- 
cumference and then stretched out, or of the circumference 
which revolves to describe the cycloid and is changed to a 
straight line. , Some demand that the construction be made 
by employing only the ruler and the compasses ; but the 
majority of geometrical problems cannot be constructed by 
this means. The question then is rather that of finding the 
proportion between the square and the circle. But this pro- 
portion not being capable of expression in finite rational num- 
bers, it has been necessary, in order to employ only rational 
numbers, to express this same proportion in an infinite series 2 

1 Christopher Clavius, 1537-1612, a Jesuit aud distinguished mathematician, 
Professor of Mathematics at Rome, and called " the Euclid of the sixteenth 
century," was employed hy Pope Gregory XIII. in the reformation of the 
calendar, for which he made the principal calculations. Among his works 
are : ' Euclidis elementorum, Rome, 1574; Sinus liness tangentes, etc., Rome, 
1586, 4to; Romani Calendarii a Gregorio XIII. P.M. restitnti Explicatio, 
Rome, 1603. His Opera mathematica, containing these and several other 
works, appeared at Mayence, 1612, 5 vols., fol. — Tr. 

2 Leibnitz's infinite series, which, according to Schaarschmidt, he had dis- 
covered before he became acquainted with Huygens, and also before his 

discoveryof the infinitesimal calcul us-, is - = 1 — - + - — -~rx~ 7; + 7^ - - - > an d 

4 o 5 / 9 11 13 



ch. in] ON HUMAN UNDERSTANDING 425 

of these numbers, which I have assigned in a manner quite 
simple. Now we should like to know whether there is not 
some finite quantity, although it be irrational only, or more 
than irrational, which can express this infinite series, that is 
to say, whether we can find exactly an abbreviated expression 
for this series. But finite, especially irrational, expressions, if 
we proceed to the most irrational of all, may vary in too many 
ways for us to be able to make an enumeration of them or to 
determine easily all that they are capable of. There might be 
perhaps a means of doing it if this irrationality should be ex- 
plained by an ordinary, or even more, an extraordinary equa- 

as related to unity it expresses the proportion obtaining between the circle 
and the circumscribed square. Cf. Be vera proportione circuit ad quadratum 
circumscriptum in numeris rationalibus, "Acta Erud. Lips.," February, 1682, 
p. 41 sq., Gerhardt, Leibniz, math. Schrift., II., 1 [Vol. 5], 118, Dutens, Leib- 
nit. op. om., 3, 140 sq. ; Quadratura arithmetica, "Acta Erud. Lip.," April, 
1691, p. 180, Gerhardt, Leibniz, math. Schrift., II., 1 [Vol. 5], 130, Dutens, 
3, 242; also letter to Conring, Jau. 3, 1678, Gerhardt, Leibniz, philos. Schrift., 
1, 187. 

The problem of which Leibnitz here speaks is tbe modern form of the prob- 
lems of the rectification and quadrature of the circle or the calculation and 
construction of 7r and of a square mathematically exactly equal in area to a 
given circle. In referring to it he distinguishes between an "ordinary," or 
algebraic, and an "extraordinary," or, as it is now termed, transcendental 
equation. The problem is to prove that ir cannot be the root of any equation 
having whole numbers for coefficients, or that w is not algebraical. The quad- 
rature of the circle has long been known to be an unsolvable problem, — Leib- 
nitz knew this, — but the impossibility of its solution has only recently been 
demonstrated. Not until mathematicians possessed the methods furnished by 
the theory of definite integrals and the departments of higher algebra devel- 
oped in the last few decades was this demonstration possible. With the aid 
of these methods Prof. Lindemann of Konigsberg succeeded, in June, 1882, in 
demonstrating with exactness the non-algebraic character of tt, and thus 
proved for the first time that the rectification and the squaring of the circle 
with rider and compasses is impossible. For his proof, cf. Uber die Ludolph'sche 
Zahl, in the " Sitzungsberichte d. kongl. Pr. Akad. d.Wiss., zu Berlin," June 
22, 1882, pp. 679-682; the " Comptes Rendus " of the French Academy, Vol. 
115, pp. 72-74, " Math. Annalen," Vol. 20, pp. 213-225. 

For an historical sketch of the problem of circle-quadrature, cf. Holtzen- 
dorff and Virchow, Sammlung gemeinverstdndlicher vnssenschaftlicher Vor- 
trage, Heft 67 ; an article from this by H. Schubert, in " The Monist," January, 
1891, Vol. 1, No. 2, pp. 197-228, reprinted in Smithsonian Report, 1890, pp. 97- 
120; and the article " Squaring of the Circle," in the Encyclop. Brit., 9th ed., 
Vol. 22, pp. 450-454 (American Reprint). On Leibnitz's relation to the prob- 
lem, cf. Kummer, Festrede am Leibniztage, in the " Monatsberichte d. Pr. 
Akad. d. Wiss.," July, 1867, p. 387 sq., an article which, while not directly 
taking into consideration the present interesting passage for the history of 
mathematics, is admirable in its understanding of the peculiarities of Leib- 
nitz's method of thought. — Tr. 



426 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

tion, which would introduce the irrational or even the unknown 
quantity into the exponent, 1 for which, however, an extended 
calculation would be required, and in which the difficulty will 
not easily he solved unless we some day find a short method for 
its solution, /But to exclude all the finite expressions is impos- 
sible, as I myself know, and to determine exactly the best is 
an immense task. And all this shows us . that the human 
mind proposes questions so strange, especially when the infinite 
enters therein, that we must not be astonished if there is some 
difficulty in making them out, so much the more as all depends 
often on a short method in these geometrical matters, which 
cannot always be determined on, just as fractions cannot 
always be reduced to the lowest terms or the divisors of a 
number be found. It is true that we may always have these 
divisors if they are possible, because their number is finite ; 
but when what we have to examine is infinitely variable and 
ascends by degrees, we are not its master though we wish to 
be, and it is too laborious to do all that is necessary in order 
to attempt methodically to reach the short method or the rule 
of progression exempting us from going farther. And as its 
usefulness does not correspond to the labor, its success is left 
to posterity, which will be able to enjoy it when this labor or 
prolixity is diminished by the new preparations and means 
which time may furnish. Unless the . persons who devote 
themselves from time to time to these studies determine to do 
properly what is necessary in order to further progress, we 
cannot hope to advance much in a short time. And we must 
not think that all is done, since indeed in ordinary geometry, 
we still have no method for determining the best constructions 
when the problems are a little complex. A certain progres- 
sion of synthesis should be mixed with our analysis in order 
the better to succeed. And I remember to have heard it said 
that the Pensionary De Witt 2 had some thoughts on this 
subject.] 

1 Cf. Letter to Arnauld, Gerhardt, Leibniz, philos. Schrift., 2, 61, 62, Janet, 
(Euvres philos. de Leibniz, 1, 622. — Tr. 

2 John De Witt, 1625-1672, an illustrious Dutch statesman, was a steadfast 
opponent of the House of Orange, whose re-elevation to power in the United 
Provinces he labored earnestly and for many years successfully to prevent. 
His plans for his country were finally defeated by the diplomacy of Louis 
XIV., the opposition of the Calvinist clergy, and the change in the popular 



ch. in] ON HUMAN UNDERSTANDING 427 

Ph. There is, indeed, another difficulty, to know whether a 
purely material being thinks or not, 1 and perhaps we shall never 
be capable of knowing this, although we have ideas of matter 
and of thought, for the reason that it is impossible for us to 
discover by contemplation of our own ideas without revelation, 
whether God has not given to some masses of matter, fitly dis- 
posed, the power to perceive and to think, or whether he has 
not united and joined to matter so disposed an immaterial 
substance that thinks. For as regards our notions, it is no 
more difficult for us to conceive that God, if he pleases, can 
add to our idea of matter the faculty of thinking, than to under- 
stand that he joins to it another substance with the faculty of 
thinking, since we know not wherein thinking consists, nor to 
what kind of substance this all powerful Being has been 
pleased to give that power, which cannot exist in any created 
being save by virtue of the good pleasure and the bounty of 
the Creator. 

Th. [This question is without doubt incomparably more 
important than the preceding ; . but I venture to say to you, 
sir, that I wish it were as easy to touch souls in order to 
influence them for their good, and to heal bodies of their 
diseases, as I think it is in our power to determine this ques- 
tion. I hope you will admit at least that I can advance with- 
out offending against modesty and without speaking as a master 
in default of good reasons ; for besides speaking only accord- 
ing to received and common opinion, I think I have brought 
thereto an attention not common. In the first place, I grant 
you, sir, that when we have only confused ideas of thought and 
of matter, as is ordinarily the case, we must not be astonished 
if we do not see the means of solving such questions. As I 
remarked a little before, one who has only the ideas of the 
angles of a triangle commonly held will never think of finding 

feeling towards the Prince of Orange, occasioned by the recollection of their 
country's obligations to his ancestors. He was massacred, with his brother 
Cornelius, in the revolution which put the Prince William (afterwards William 
III. of England) at the head of the United Provinces. He published Elementa 
linearum curvarum, Leyden, 1G50; The Hague, 1709. — Tr. 

1 Cf. ante, p. 56 sq., where Leibnitz shows that Locke afterwards gave up 
the opinion which he once advanced as possible that matter can think. For Leib- 
nitz, who regards matter as a mere phenomenon and not a reality, the question 
does not exist. — Tr. 



428 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

them always equal to two right angles. We must consider 
that matter taken as a complete being (i.e. secondary matter in 
distinction from the primary, which is something purely passive 
and consequently incomplete) is only a mass, or that which 
results therefrom, and that every real mass supposes simple 
substances or real unities, and when we further consider what 
belongs to the nature of these real unities, i.e. perception and 
its consequences, we are transferred so to speak into another 
world, that is to say into the intelligible world of substances 
while before we have been only among the phenomena of the 
senses. And this knowledge of the interior of matter shows 
us sufficiently its natural capability, and that whenever God 
shall give it organs suitable for rational expression, the imma- 
terial substance which reasons will not fail to be given it also, 
in virtue of that harmony which is also a natural consequence 
of substances. Matter cannot subsist without immaterial 
substances, i.e. without the unities ; after which the question 
should no longer be asked whether God is free to give them to 
it or not ; and if these substances had not in themselves this 
correspondence or harmony of which I have just spoken, God 
would not act in accordance with the natural order. To speak 
in an entirely simple manner of giving or according powers is 
to return to the naked faculties of the schoolmen and to im- 
agine minute self-subsisting entities, which may go in and out 
like pigeons from a pigeon-house. It is making substances of 
them without being aAvare of it. The primitive powers con- 
stitute substances themselves, and the derivative powers, or, if 
you prefer, the faculties, are only modes of being, which must 
be derived from substances, and are not derived from matter 
so long as it is only a machine, i.e. so long as it is abstractly 
considered only as the incomplete essence of primary matter, or 
passivity pure and simple. As to which I think you will 
agree, sir, that it is not within the power of mere mechanism 
to produce perception, sensation, reason. They must then 
spring from some other substantial thing. To desire God to 
act otherwise and to give to things accidents which are not 
modes of being or modifications derived from substances, is to 
have recourse to miracles and to what the schoolmen, called the 
obediential power, by a kind of supernatural exaltation, as when 
certain theologians claim that the fire of hell burns up sepa 



en. in] ON HUMAN UNDEESTANDING 429 

rated souls. In which case it may indeed be doubted whether 
it was the fire that acted or whether God did not himself 
produce the effect, acting in place of the fire.] 

Ph. You surprise me somewhat by your elucidations, and 
you anticipate me in many of the things I was going to say 
to you upon the limits of our knowledge. I should have said 
to you that we are not in a state of vision, as the theologians 
call it, that faith and probability must suffice us as regards 
many things, and particularly as regards the immateriality of 
the soul; that all the great ends of morality and religion are 
established upon sufficiently good foundations without the aid 
of the proofs of this immateriality drawn from philosophy ; 
and that it is evident that he who ■ has begun to make us sub- 
sist here as sensible and intelligent beings, and who has pre- 
served us many years in this state, can and will make us enjoy 
also a similar state of sensibility in the other life, and make 
us capable of receiving there the retribution he has designed 
for men according as they shall have conducted themselves in 
this life ; in fine that we may judge by this that the necessity 
to determine for or against the immateriality of the soul is not 
so great as some people too zealous for their own views have 
wished to persuade us. [I was going to say all this to you, 
and more besides to the same effect, but I see now how differ- 
ent is the statement that we are sensible, thinking, immortal 
beings by nature and the statement that we are so only by mir- 
acle. It is a miracle, in fact, which I know I must admit if the 
soul is not immaterial ; but this view of miracle, besides being 
without foundation, will not produce a sufficiently good effect in 
the minds of most people. I see clearly also from the way you 
understand the matter, that we can decide rationally as regards 
the present question, without finding it needful to depart to 
the enjoyment of the state of vision and to find ourselves in the 
company of those superior spirits who penetrate very deeply 
into the internal constitution of things and whose living and 
penetrating sight and vast field of knowledge may make us 
imagine by conjecture what happiness they must enjoy.] I 
had supposed it entirely beyond our knowledge to combine sen- 
sation with extended matter, and existence with a thing which has 
absolutely no extension. I had therefore become convinced that 
those who took sides here followed the unreasonable method 



430 LEIBNITZ'S CRITIQUE OE LOCKE [ B k. iv 

of certain persons, who, seeing that things considered from a 
certain side are incomprehensible, throw themselves headlong 
upon the opposite side, although it is no less unintelligible ; a 
procedure which arose in my opinion from the fact that some 
having their mind too deeply buried so to speak in matter, 
could not accord any existence to that which is not material ; 
and others not finding that thought is included in the natural 
faculties of matter, concluded that God himself could not give 
life and perception to a solid substance without putting therein 
an immaterial substance ; while I now see that if He had done 
so it would be by a miracle, and that this incomprehensibility 
of the union of the soul and the body or of the union of sensa- 
tion with matter seems to cease through your hypothesis of •pre- 
established harmony between different substances.] 

Th. [In fact there is nothing unintelligible in this new 
hypothesis, since it attributes to the soul and to bodies only 
the modifications which we experience in ourselves and in 
them ; and only makes them appear more regular and more 
connected than has been thought hitherto. The difficulty 
which remains exists only as regards those who wish to imagine 
what is only intelligible, 1 as if they wished to see sounds or hear 
colors, and these are they who refuse existence to everything 
which is net extended, a view which will compel them to refuse 
it to God himself, i.e. to renounce the causes and reasons of 
changes and of such changes : these reasons being incapable of 
arising from extension and from natures purely passive, 
and not indeed wholly from particular and inferior active 
natures without the pure and universal act of the supreme 
substance.] 

Ph. One objection remains for me with reference to things 
whose matter is naturally susceptible of feeling. The body 
so far as we can conceive it, is capable only of striking and 
effecting a body, and motion can produce nothing but motion : 
so that when we agree that the body produces pleasure or 
pain or the idea of a color or sound, we seem compelled to 
abandon our reason, to go beyond our own ideas, and to at- 
tribute this production solely to the good pleasure of our 
Creator. What reason have we then to conclude that it is 
not the same with perception in matter ? I almost see what 
i Cf. ante, p. 274, note 2. — Tr. 



ch. in] ON HUMAN UNDERSTANDING 431 

reply you can make, and although you have already said some- 
thing regarding it more than once, I understand you better 
now, sir, than I have done. But I shall be very glad to hear 
further what reply you will make regarding it upon this 
important occasion. 

Th. [You rightly judge, sir, that I shall say that matter 
cannot produce pleasure, pain, or thought in us. It is the soul 
itself which produces them in conformity to what takes place 
in matter. And some clever people among the moderns begin 
to declare that they understand occasional causes only as I. 
Now this being posited, there occurs nothing unintelligible, 
except that we cannot distinguish all that enters into our con- 
fused perceptions, which contain even the infinite, and which 
are the detailed expression of what occurs in bodies. As for 
the good pleasure of the Creator, it must be said that he is 
ruled by the natures of things, so that he produces and con- 
serves therein only what suits them and can be explained, at 
least in general, by their natures ; for the detail often sur- 
passes us as much as the care and power of arranging the 
grains of a mountain of sand according to the order of the 
figures, although there is here nothing difficult to understand 
but the multitude. Otherwise if this knowledge were in 
itself beyond us, and if we could not indeed conceive the rea- 
son of the relations of the soul and body in general, in fine, 
if God gave to things accidental poioers detached from their 
natures, and consequently removed from reason in general, 
there would be a back door for calling back the too occult quali- 
ties which no mind can understand, and these little goblins of 
facidties incapable of reason, 

Et quidquid Schola finxit otiosa : 

helpful goblins who proceed to appear like the gods of the 
theatre, or like the fairies of the Amadis, and who will do at need 
all that a philosopher wishes, without ceremony and without 
tools. But to attribute the origin of these powers to the good 
pleasure of God appears to me a thing not quite congruous with 
him who is the supreme reason, with whom everything is 
regular, everything consistent. This good pleasure would not 
indeed be good, nor pleasure, if there were not a perpetual 
parallelism between the power and the wisdom of God.] 



432 LEIBNITZ'S CEITIQUE OF LOCKE [bk. iv 

§ 8. Ph. Our knowledge of identity and diversity goes as far 
as our ideas, but that of the connection of our ideas, §§9, 10. 
as regards their coexistence in one and the same subject is 
very . imperfect and almost nothing § 11. especially as regards 
secondary qualities as colors, sounds, and tastes § 12. because 
we do not know their connection with the primary qualities, 
i.e. § 13. how they depend upon size, figure, or motion. § 15. 
We know a little more of the incompatibility of the secondary 
qualities ; for a subject cannot have, for example, two colors 
at the same time, and when they seem to be seen in an opal or 
in an infusion of lignum nephriticum, it is in different parts of 
the object. § 16. It is the same with the active and passive 
powers of bodies. Our researches in this direction must depend 
on experience. 

Th. [The ideas of sensible qualities are confused, and the 
powers which should produce them furnish in consequence only 
ideas into which some confusion enters : thus the connections 
of these ideas can be known otherwise than by experience 
only as they are reduced to the distinct ideas which accom- 
pany them, as has been done (for example) in regard to the 
colors of the rainbow and of prisms. And this method pre- 
sents a beginning in analysis which is of great use in physics ; 
and by following it I doubt not that medicine in time will 
find itself considerably more advanced, especially if the public 
is a little better interested than hitherto.] 

§ 18. Ph. As for the knowledge of relations it is the largest 
field of our knowledge and it is difficult to determine how far 
it may extend. Progress depends on our sagacity in finding 
intermediate ideas. Those who are ignorant of algebra cannot 
imagine the wonderful things that may be done in this field 
by means of this science. And I do not see that it is easy to 
determine what new means of perfecting other parts of our 
knowledge may yet be found out by a penetrating mind. At 
least the ideas regarding quantity are not the only ones capable 
of demonstration ; there are others, perhaps the most important 
part of our contemplation, from which we might deduce certain 
knowledge, if vices, passions, and domineering did not directly 
oppose the execution of such enterprise. 

Th. [Nothing is truer than what you, sir, here say. What 
is there more important, supposing it is true, than what I be- 



ch. m] ON HUMAN UNDERSTANDING 433 

lieve we have determined upon the nature of substance, upon 
unity and multiplicity, upon identity and diversity, upon the 
constitution of individuals, upon the impossibilities of void 
and atoms, upon the origin of cohesion, upon the law of con- 
tinuity, and the other laws of nature ; but chiefly upon the 
harmony of things, the immateriality of souls, the union of 
the soul and the body, the conservation of souls, and even of 
the animal after death. And there is nothing in all this which 
I do not think demonstrated or demonstrable.] 

Ph. [It is true that your hypothesis appears extremely con- 
sistent and of great simplicity : a clever man in France who 
desired to refute it, admits publicly that he was impressed by 
it. And it is a simplicity very different from that which I see. 
It will be well to show this doctrine more and more in its true 
light. But in speaking of things which are of most importance 
to us, I thought of morality to which I admit your metaphysic 
gives wonderful foundations : but without digging so deep, it 
has sufficiently firm foundations, although perhaps they do not 
extend as far (as I remember that you remarked) when a nat- 
ural theology like yours is not their base. Yet the considera- 
tion of the goods of this life alone already serves to establish 
important consequences for regulating human society. We 
can estimate justice and injustice as incontestably as in math- 
ematics ; for example this proposition : There cannot be injustice 
where there is no property, is as certain as any demonstration 
which is in Euclid ; property being the right to a certain thing, 
and injustice the violation of a right. It is the same with this 
proposition : iVo government allows absolute liberty. For gov- 
ernment is the establishment of certain laws, whose execution 
it demands, and absolute liberty is the power each one has of 
doing whatever he pleases. 

Th. [You use the word property a little differently from its 
ordinary use, for you mean by it the right of one person to a 
thing to the exclusion of the right of another. Thus if there 
were no property, as if all were common, there nevertheless 
might be injustice. By thing in the definition of property you 
must also further understand action ; for otherwise, if there 
were therein no right to things, it would be always an injustice 
to prevent men from acting where they find it needful. But 
according to this explanation it is impossible that there be no 
2f 



434 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

property. As for the proposition concerning the incompati- 
bility of government with absolute liberty, it belongs to the 
number of the corollaries, i.e. the propositions, which it is 
sufficient to point out. There are some in jurisprudence which 
are more complex, as for example, those concerning what is 
called jus accrescendi, 1 concerning the conditions and many 
other matters ; and I indicated them when I published in 
my youth some theses upon the conditions, in which I demon- 
strated some of them. And if I had leisure, I would retouch 
them. 2 ] 

Ph. [That would afford pleasure to the curious, and serve 
to anticipate any one who might reprint them without re- 
vision.] 

Th. [That is what happened to my " Ars Combinatoria," 3 as 
I have already complained. It was a fruit of my early youth, 
and yet it was reprinted a long time after without consulting 
me and without indicating even that it was a second edition, 
and this made some think to my prejudice that I was capable 

1 Cf. Poste, Gaius, Elements of Roman Law, Bk. II., 199 (p. 262, 3d ed., 
Oxford, 1890) : " Illud constat si duobus pluribusve per vindicationem eadern 
res legata sit, sive conjunctirn, sive disjunctim, si omnes veniant ad legatum, 
partes ad siugulos pertinere, et deficieutis portionem collegatario adcrescere." 
Also Sandars, Inst, of Justinian, Lib. II., Tit. XX., 8 (p. 226, 8tb ed., London, 
1888) : "Si eadem res duobus legata sit, sive conjunctiru sive disjunctim: si 
ambo perveniant ad legatum, scinditur inter eos legaturn; si alter deficiat, 
quia aut spreverit legatum, aut vivo testatore decesserit, vel alio quolibet 
modo defecerit, totum ad collegatarium pertinet." 

In reference to the Jits accrescendi — the law of increase — Sandars says, 
p. 198 : " If any one instituted heir died before the testator, or refused to take 
his share of the inheritance, his share was, in fact, undisposed of. But as the 
testator was always supposed to have disposed of his whole estate, if he dis- 
posed of any part, this share was divided among all those who entered on the 
inheritance in proportions corresponding to the share given them by the will. 
Their claim was called the 'jus accrescendi.' " — Tr. 

2 Leibnitz here refers to his thesis Be conditionibus, which he defended 
under the presidency of Prof. Leonhard Schwendendorfer, at Leipzig, in 1665. 
Guhrauer states (cf. Leibniz, eine Biographie, Pt. I., pp. 36-37) that we do 
not know the treatise in its original form, but in the revision and rearrange- 
ment of its material made by Leibnitz in 1672, in a collection of his juristic 
treatises under the title Specimina juris, and which is found in Dutens, Leib- 
nit. op. om., 4, Pt. III., 92 sq. — Tr. 

3 The Bissertatio de Arte Combinatoria, cf. Gerharclt, 4, 27 sq., Erdmann, 
6 sq., Dutens, 2, Pt. I., 341 sq., appeared at Leipzig in 1666. The pirated edi- 
tion here referred to by Leibnitz was published at Frankfort, 1690, and re- 
viewed by him in the " Acta Erud.," February, 1691. Cf. Guhrauer, Ijeibniz. 
eine Biog., Pt. I., pp. 37-38, and Anmerkungen z. erst. Buche, pp. 7, 8; 
Dutens, 6, 295.— Tr. 



en. m] ON HUMAN UNDERSTANDING 435 

of publishing such a piece in my mature years ; for although 
it contains thoughts of some consequence, which I still ap- 
prove, it also contains some which could become only a young 
student.] 

§ 19. Ph. I find that diagrams are a great remedy for the 
uncertainty of words, but they cannot have place in moral 
ideas. Most moral ideas are more complex than the diagrams 
ordinarily considered in mathematics ; thus the mind finds it 
difficult to retain the precise combinations of what enters into 
moral ideas, in a manner as perfect as is necessary in long de- 
ductions. And if in arithmetic the different stages are not 
designated by marks whose precise meaning is known, and 
which last and remain in sight, it is well-nigh impossible to 
make extended computations. § 20. Definitions furnish some 
remedy provided they are constantly employed in ethics. And 
for the rest, it is not easy to foresee what methods may be 
suggested by algebra or by some other means of this nature to 
remove other difficulties. 

Th. [The late Erhard Weigel, 1 a mathematician of Jena in 
Thuringia, ingeniously invented diagrams to represent moral 
things ; and when the late Samuel Puffendorf, 2 his disciple, pub- 

1 Erhard Weigel, 1625-1699, a distinguished German mathematician and 
astronomer, was professor of mathematics in Jena from 1653 on, where he was 
Leihnitz's first teacher in the suhject, when he studied there in 1663, cf. 
Guhrauer Leibniz, eine Biographie, Pt. I., pp. 26, 32. The Diet of Ratishon 
appointed him to organize a commission for the correction of the calendar. 
He also labored earnestly for the reform of the school system in Germany, 
travelling through the country in 1696 for this purpose, cf. Guhrauer, op. cit., 
Pt. II., pp. 211-214, and the correspondence of Leibnitz and Placcius, from 
Feb. 12, 1696 on, Dutens, Leibnit. op. om., 6, 61 sq. 

Weigel, who was a philosopher, moralist, and an original investigator of 
the law of nature {Naturrecht) as well as a mathematician, published many 
works, among them the Expose arithmetique de la morale, or, as the German 
title runs, Arithmetische Beschreibung tier Moralweisheit von Personen und 
Sachen, woraus das gemeine Wesen besteht, nach der pythagorischen Kreutz- 
zahl in lauter tetraktische Glieder eingetheilt, Jena, 1674, 4to, in which he 
attempted a mathematical exposition of moral philosophy, based upon the 
Pythagorean principle that the essence of things consists in numbers. Leibnitz 
thus speaks of this book in the Miscellanea, No. CLIIL, Dutens, 6, 325 : " M. 
Weigelius a fait un excellent livre en Allemand sur la morale eclairee par 
les nombres, et je ne crois pas que les Pythagoriciens ayent rien dit de plus 
beau sur ce chapitre." For further remarks of Leibnitz on Weigel, cf. 
Guhrauer, Leibnitz's deutsche Schriften, 2, 473 sq. — Tr. 

2 Samuel Pufendorf, 1632-1694, was one of the greatest German publicists 
and historians, and one of the founders of the science of public law. He 
studied at Jena under Weigel, with whom he formed an intimate friendship, 



436 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

lished his " Elements of universal Jurisprudence " sufficiently 
conformed to the thoughts of Weigel, there was added thereto 
in the Jena edition the " Moral Sphere "of this mathematician. 
But these diagrams are a kind of allegory nearly like the table 
of Cebes, 1 but less popular and serving the memory in the re- 
tention and arrangement of its ideas rather than the judgment 
in the acquisition of demonstrative knowledge. They do not 
cease to have their use in arousing the mind. Geometrical 
diagrams appear simpler than moral things ; but they are not 
so, because continuity includes the infinite from which it must 
be chosen. For example, to cut a triangle into four equal 
parts by two straight lines perpendicular to each other is a 
question apparently simple but really quite difficult. It is not 
the same in questions of morality since they are determinable 

and to whose teaching and influence he largely owes the orderly method and 
mathematical precision and dryness which characterize his style, and that 
independence of character which never yielded to the " ipsedixitism " of other 
writers, however high their position and authority. Among his works are: 
Momenta jurisprudentix universalis, cum appendice de Spheera morali (of 
Weigel), Hag. Com., 1660, 12mo — also Jena, 1660, " bei Meyer " ; the ed. here 
meant by Leibnitz, according to Schaarschmidt, who states that in the 2d 
Jena ed., 1669, the Sphsera moralis occurs, p. 313 sq., — the book which obtained 
for him from the elector Charles Louis, to whom it was dedicated, the newly 
created chair of the law of nature and of nations at Heidelberg; De statu 
imperii germanici, Geneva, 1667, — the book which first called forth Leibnitz's 
aversion and criticism, — small in bulk, but great in significance, in which he 
criticised the political organization of the empire, suggested a remedy for the 
evils therein, and revealed himself as a consummate statesman, subsequent 
events proving the justness of his conclusions; and the work on which his 
fame chiefly rests, De jure naturse et gentium, 1672, trans, into French, with 
notes, by Barbeyrac, Amsterdam, 1712, and into English by Basil Kennett, 
London, 1729, and resume of the same, De officio hominis et civis, 1675. 

For Leibnitz's criticism of Pufendorf and his work, — the severest, perhaps, 
he ever made on any one, and through which he is, to a considerable extent, 
responsible for the failure of posterity justly to estimate and acknowledge 
its debt to him, — cf. letter to Kestner, No. 7, § 2, Dutens, 4, Pt. III., 261; 
Monita qusedam ad S. Puffendorfii principia, ibid., 275-283; letter to S. Kor- 
tholt, No. 3, Dutens, 5, 305 ; letters to Bierling, Gerhardt, Leibniz, philos. 
Schrift., 7, 487, 488, 490, 499, 506, 511, Dutens, 5, 355, 358, 361, 371, 386, 390 — 
Dutens gives Bierling's letters to Leibnitz also ; letter to Bourguet, G. 3, 590, 
Erdmann, 734, b., Dutens, 2, Pt. I., 334. For a comparison of the views of 
Leibnitz and Pufendorf on the ultimate foundations of natural and public law, 
cf. Monita qusedam above cited, and Guhrauer, Leibniz, eine Biog., Pt. I., 223 
sq. — Tr. 

1 Cebes of Thebes, a disciple of Socrates, distinguished for his virtue and 
love of truth; cf. Plato, Phsedo, 59 C, 60 C sq., 63 A. His mVaf, Tabula, 
or ' picture,' is, according to Zeller, Philos. d. Griech., II., 1 [Vol. 3], 242, 4th 
ed., 1889, " certainly spurious." — Tr. 



ch. m] ON HUMAN UNDERSTANDING 437 

by reason alone. For the rest it is not the place here to speak 
de proferendis scientiae demonstrandi pomoeriis, and to propose 
true means of extending the art of demonstration beyond its 
ancient boundaries which have been nearly the same up to the 
present time as those of mathematics. If God gives me the 
time necessary for it, I hope some day to publish an essay 
upon this subject, putting these means into effective use with- 
out limiting myself to precepts.] 1 

Ph. [If you carry out this plan, sir, and as it should be, 
you will infinitely oblige the Philulethes like myself, i.e. the class 
who sincerely desire to know the truth.] For truth is naturally 
agreeable to the mind, and there is nothing^ so deformed and 
so incompatible with the understanding as a lie. But men 
must not be expected to apply themselves much to these 
discoveries, so long as the desire and the esteem of riches or 
of power shall lead them to espouse opinions authorized by 
fashion, and to seek in consequence arguments either to make 
them pass as good or to varnish over and cover their deform- 
ity. And while the different parties make all men whom they 
can get into their power receive their opinions without exam- 
ining whether they are true or false, what new light can be 
hoped for in the sciences belonging to morals ? This part of 
the human race which is under the yoke, ought to expect in 
most places in the world instead of that light, darkness as 
thick as that of Egypt, were not the candle of the Lord itself 
found present in the mind of men, 2 a sacred light which all 
human power cannot wholly extinguish. 

Th. [I do not despair that at some time and in a more tran- 
quil country men will betake themselves more to reason than 
they have done. For in fact we must despair of nothing ; and 

1 Leibnitz's plan to extend and perfect the science of demonstration, or that 
part of logic which is concerned with the methods of proof, and which in his 
view was conceived up to his own time too narrowly as virtually identical 
with the method of mathematics, is closely connected, hut not identical, with 
his Universal Characteristic; cf. ante, pp. 292, note 1, 375, note 1. Leibnitz, 
however, never carried his plan into execution, but left some preliminary 
essays or sketches which serve to indicate what he thought desirable in this 
direction, and what be purposed himself some day to provide. Of. Preceptes 
pour avancer les sciences, Erdmann, Leibnit. op. philos. 165-171, published in 
a more complete form in Gerhardt, Leibniz, philos. Schrift., 7, 157 sq. ; and 
the fragment without title treating of the means of philosophical demonstra- 
tion, G^, 7, 299-301. — Tr. 2 Cf. Proverbs 20 : 27. — Tr. 



438 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

I believe that great changes for evil and for good are reserved 
for the human race, but in the end more for good than for 
evil. Suppose we see some day a great prince, who, like the 
ancient kings of Assyria or of Egypt or like another Solomon, 
reigns a long time in a profound peace, and that this prince, 
loving virtue and truth and endowed with a great and solid 
mind, takes it into his head to make men happier and more 
accommodating among themselves and more powerful over 
nature ; what wonders will he not do in a few years ? For it 
is certain that in this case more would be done in ten years 
than in a hundred or perhaps a thousand while letting things 
follow their ordinary course. Moreover, if the path were 
opened once for all, many people would enter therein as 
the geometers do, though this would be only for their pleas- 
ure and to acquire fame. The public better civilized will 
some day turn more than it has hitherto done to the advance- 
ment of medicine ; natural histories of all countries will be 
published like almanacs or like the Mercures galans; 1 no val- 
uable observation will be left without being registered ; those 
who will apply themselves thereto will be aided ; the art of 
making such observations will be perfected, and further that 
of employing them to establish aphorisms. The time will 
come when the number of good physicians having become 
greater and the number of people of certain professions of 
which there will then be less need having become proportion- 
ally less, the public will be in a condition to give more 
encouragement to natural research, and above all to the ad- 
vance of medicine, and then this important science will be 
carried far beyond its present condition and will grow apace. 
I believe indeed that this business of the police should be 
the object of the greatest care of those who govern, after that 
of virtue, and that one of the greatest fruits of good morals 
or politics will be to produce a better (science of) medicine, 

1 "Mercure galant," the title of different periodicals treating of politics, 
literature, and containing announcements, and news of various kinds; in par- 
ticular, the title of a journal founded by De Vise in 1672, and continued, with 
several short periods of suspension, under various names and editors, till 1853. 
Leibnitz, in a letter to Sebastian Kortholt, Jan. 9, 1711, inquires whether a 
complete set can be obtained, and at what price : " Discere etiam velim, an 
totus Mercurius Gallant, ut sic dicam, vulgo Mercure Galant. a Devisieo nuper 
extincto a multis annis compositus, tolerabili pretio haberi possit, et quanti? " 
(c/. Dutens, Leibnit. op. om. 5, 315). — Tr. 



ch. in] ON HUMAN UNDERSTANDING 439 

when men shall begin to be wiser than they are and the no- 
bility shall learn the better to employ their wealth and their 
power for their own welfare.] 

§ 21. Ph. As for the knowledge of real existence (which is 
the fourth kind of knowledge) it must be said that we have an 
intuitive knowledge of our existence, a demonstrative knowledge 
of that of God, and a sensitive knowledge of other things. We 
shall speak of these fully in what follows. 

Th. [You could say nothing more justly.] 

§ 22. Ph. Having now spoken of . knowledge, it appears ap- 
propriate the better to discover the present condition of our 
mind that we should consider a little the dark side and take 
knowledge of our ignorance : for it is infinitely greater than 
our knowledge. The causes of this ignorance are as follows : 
(1) Want of ideas ; (2) Inability to discover the connection 
between the ideas we have ; (3) Neglect to trace and examine 
them with exactness. § 23. As for the want of ideas, we have 
as simple ideas only those coming to us from the senses [in- 
ternal or external].' Thus as regards an infinite number of 
the creatures of the universe and their qualities we are like 
the blind as regards colors not indeed possessing the faculties 
necessary in order to their knowledge; and according to all 
appearances man holds the lowest rank among intellectual 
beings. 

Th. [I do not know but that there are also some below us. 
Why should we degrade ourselves unnecessarily? Perhaps we 
hold a sufficiently honorable rank among rational animals ; 
for superior genii may have bodies of another kind so that 
the name animal cannot agree with them. We cannot say 
whether our sun among the great number of other suns has 
more above than below it, and we are well placed in his sys- 
tem: for the earth occupies the middle course between the 
planets, and its distance appears well chosen for a contem- 
plative animal who should inhabit it. Besides we have in- 
comparably more reason to praise than to complain of our lot, 
the majority of our evils rightly being imputed to our fault. 
Above all we should be very wrong to complain of the defects 
of our knowledge, since we avail ourselves so little of that 
which charitable nature presents to us.] 

§ 24. Ph. It is, however, true that the extreme distance of 



440 LEIBNITZ'S CRITIQUE OF LOCKE [be. iv 

nearly all parts of the world which, are exposed to our sight 
conceals them from our knowledge, and apparently the visible 
world is only a small part of this immense universe. We are 
confined in a small corner of space, i.e. in the system of our 
sun, and yet we do not know even what takes place in the 
other planets which as well as our ball revolve about it. 
§ 25. This knowledge escapes us by reason of size and dis- 
tance ; but other bodies are concealed from us because of their 
minuteness ; and these are the ones which it would most con- 
cern us to know ; for from their contexture we could infer the 
use and operation of those which are visible, and know why 
rhubarb purges, hemlock kills, and opium produces sleep. 
Thus § 26. whatever distance human industry may advance 
experimental philosophy upon physical things, I am compelled 
to believe that we can attain upon these matters a scientific 
knoioledge. 

Th. [I fully believe that we shall never advance so far as 
will be desirable ; but it seems to me that some considerable 
progress will be made in time in the explication of certain 
phenomena, because the large number of experiments which 
we are led to make may furnish us data more than sufficient, 
so that only the art of employing them will be lacking, (an 
art) the small beginnings of which I do not despair of seeing 
pushed forward, since the infinitesimal analysis 1 has given us 
the means of uniting geometry with physics, and dynamics has 
furnished us with the general laws of nature.] 

§ 27. Ph. Spirits are still further removed from our knowl- 
edge ; we cannot form any idea of their different orders, and 
yet the intellectual world is certainly grander and more beau- 
tiful than the material world. 

Th. [These worlds are always perfectly parallel as regards 
efficient causes, but not as regards final. For in proportion as 
spirits rule in matter they produce therein wonderful arrange- 
ments. This appears in the changes men have made, in order 
to embellish the earth, as little gods imitating the great archi- 
tect of the universe, though only by employing bodies and 

1 Sir Isaac Newton, 1642-1727, in his Principia, was the first to apply in a 
systematic way the infinitesimal calculus to physics, after that Galileo, 1564- 
1642, had paved the way for a theory of universal gravitation hy his deter- 
mination of the law of acceleration in falling hodies. — Te. 



ch. in] ON HUMAN UNDEKSTANDING 441 

their laws. What may not be conjectured concerning this 
immense multitude of spirits which surpass us? And as 
spirits form all together a kind of state under God, whose gov- 
ernment is perfect, we are far removed from comprehending 
the system of this intelligible world and from conceiving the 
punishments and rewards prepared for those who deserve 
them according to the most exact standard, and from imagin- 
ing what eye has not seen, nor ear heard, nor has ever entered 
into the heart of man. But all this shows that we have all 
the distinct ideas necessary for knowing bodies and spirits, 
but not sufficient detail of facts, nor senses penetrating enough 
to distinguish confused ideas or sufficiently extended to per- 
ceive them all.] 

§ 28. Ph. As for the connection, the knowledge of which 
is wanting to us in the ideas which we have, 1 was going to 
say to you that the mechanical affections of bodies have no 
connection with the ideas of colors, sounds, smells, tastes, 
pleasure, and pain; and that their connection depends only 
upon the good pleasure and the arbitrary will of God. But I 
remember that you think there is a perfect correspondence, 
although this is not always an entire resemblance. But you 
recognize that the too great detail of small things entering 
therein hinders us from discerning that which is concealed, 
though you hope still that we shall make much advance there- 
in ; and that thus you do not wish to say with my illustrious 
author (§ 29), that it is labor lost to engage in such a search, from 
fear that this belief would injure the growth of science. I 
should have spoken also of the difficulty which has hitherto 
been found in explaining the connection between the soul and 
the body, since a thought cannot be conceived as producing a 
motion in the body, nor a motion as producing a thought in 
the mind. [But since I comprehend your hypothesis of pre- 
established harmony, this difficulty of which they despaired 
appears to me removed at once, and as it were, by magic] 
§ 30. There remains then the third cause of our ignorance, 
viz. that we do not follow the ideas we have or may have, 
and do not apply ourselves to finding intermediate ideas. 
Thus it is that we are ignorant of mathematical truths, al- 
though there is no imperfection in our faculties, nor any 
incertitude in the things themselves. The bad use of words 



442 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

has contributed the most to prevent us from finding the agree- 
ment or disagreement of ideas ; and the mathematicians who 
form their thoughts independently of names and accustom 
themselves to present to their minds the ideas themselves in- 
stead of their sounds, have thereby escaped a great deal of 
embarrassment. If men had acted in their discoveries in the 
material world as they have been wont to do in regard to 
those having reference to the intellectual world, and if they 
had been wholly lost in a chaos of terms of an uncertain mean- 
ing, they would have disputed endlessly about the zones, the 
tides, the building of vessels, and the routes; they would 
never have gone beyond the line, and the antipodes would 
still be as unknown as they were when to maintain them was 
declared a heresy. 

Th. [This third cause of our ignorance is the only blamable 
one ; and you see, sir, that the despair of further advance is 
therein contained. This discouragement does much injury; 
and persons of ability and importance have hindered the 
progress of medicine by the false persuasion that it is labor 
lost to work therein. When you see the Aristotelian philoso- 
phers of past time speak of meteors, as the rainbow, for 
example, you will find that they believed they should not 
think alone of explaining distinctly this phenomenon; and the 
attempts of Maurolycus, 1 and afterwards of Marc Antony de 
Dominis 2 appeared to them like the flight of Icarus. But the 

1 Francesco Maurolico, 1494-1575, a celebrated Italian mathematician, 
whose father, a Greek, came originally from Constantinople, taught mathe- 
matics at Palermo, Naples, Rome, and Messina. In his Treatise on Conies he 
sought for the first time to deduce the properties of these curves from the 
corresponding curves in the circle of which they are the perspective. He first 
introduced secants into trigonometrical calculations, constructing and publish- 
ing a table of them in his Theodosii sphsericorum, Messina, 1558, fol. He also 
investigated the structure of the eye, seeking therein the explanation of the 
phenomena of vision. He described exactly the course of the rays of light 
across the cornea and the crystalline lens, but stopped in utter astonishment 
when he discovered that his theory led him to admit that the images of objects 
upon the retina are found inverted. The work of Maurolico, here referred to by 
Leibnitz, is his Problemata ad perspectivam et iridetn pertinentia, appended 
to his Photismi [or Theoremata~\ de lumine et umbra adperspectivam radiorum 
incidentium, Venice, 1575, 4to, new ed., with notes of Clavius, Lyons, 1613. — Tr. 

2 M. Ant. de Dominis, 1566-1624, a native of Dalmatia, was professor of 
eloquence, philosophy, and natural sciences at the University of Padua. 
Though archbishop of Spalatro, he was republican in his views of the consti- 
tution and administration of the church and strongly opposed to the doctrine 



ch. in] ON HUMAN UNDEESTANDING 443 

sequel has disabused the world of this. It is true that the 
bad use of terms has caused a good part of the confusion 
found in our knowledge, not only in ethics and metaphysics, 
or in what is called the intellectual world, but also in medi- 
cine where this abuse of terms increases more and more. We 
cannot always aid ourselves with figures as in geometry : but 
algebra shows us that great discoveries may be made without 
recurring always to the ideas themselves of things. In ref- 
erence to the pretended heresy about the antipodes I will say 
in passing that it is true that Boniface, x Archbishop of May- 
ence, accused Virgil of Salzburg, 2 in a letter, which he wrote 

of papal supremacy. While in England he published his views in his De 
republica ecclesiastica, London, 1617-1620, reprinted Frankfort, 1658, both eds., 
3 vols., fol. For some specimen quotations from this book, cf. Larousse, 
Grande Diet. Univ. de XIX" Siecle, Vol. 6, p. 1068, a. Returning to Italy, he 
and his book were condemned as heretical, in spite of his retraction of his 
errors, and he was imprisoned, and probably poisoned, in the Castle of St. 
Angelo, and his body exhumed and burned with great ceremony in the Campo 
de' Fiori in Rome in January, 1625. 

In his Be radiis visus et lucis in vitris perspectivis et iride, Venice, 1611, 
4to, cited with high praise by Newton in his Optics, he presented to the world 
the first attempt at a theory of the rainbow. He successfully reflected rays 
of light through the interior of raindrops before making them come out again, 
but could not account for the angle at which the observer sees the ray of the 
bow. On his theory, cf. Venturi, Commentarii sopra la storia e le teorie dell' 
ottica, Bologna, 1814, Vol. 1, p. 149. Of the De radiis visus et lucis, chap. 9 
and chap. 13, "Vera iridis tota generatio exjrficatur," are printed in Libri, 
Histoire des Sciences math, en Italie depuis la Renaissance jusqu'a la fin du 
XVII e siecle, 1838-1841, 4 vols., 8vo, Vol. 4, p. 436 sq. Leibnitz thus speaks 
of him in the Miscellanea Leibnitiana, ed. Feller, No. CXV., p. 198 (cf. also 
Dutens, Leibnit. op. om., 6, 319): " Elegantissime materiam tractavit de- 
monstrationibusque mathematicis confirmavit. Iridis etiam et nonnullorum 
aliorum ejusmodi meteorum causam ab Aristotele assignatam recte ex- 
pend it." — Tr. 

1 Boniface ("Winfrid, the Anglo-Saxon Benedictine monk, named Bonifa- 
cius by Pope Gregory II.), 680-755, the apostle to the Germans, became arch- 
bishop of Mayence (Mainz) in 748. On his life and labors, cf. Neander, Hist. 
of the Christ. Relig. and Church, 3, 46 sq. ; Smith and Wace, Diet, of Christ. 
Biog., Vol. 1, p. 324. His Opera quse extant omnia, ed. J. A. Giles, Londini, 
1844, 2 vols., 8vo; also in Migne, Patrol, s. Lot., Vol. 89, Paris, 1863. His 
letters were edited, with notes, by the Jesuit Nic. Serarius, 1555-1609, Mayence, 
1605 and 1629, 4to; and by Wiirdtwein, Moguntise, 1789, fol.— Tr. 

2 St. Fergil, best known by the Latinized form of his name, — Virgilius, — 
was an Irish priest from Aghavoe, Queen's Co., who came to Bavaria, became 
at first abbot of St. Peter's monastery in Salzburg, and finally, on the martyr- 
dom of Boniface, 755, and the death of John, bishop of Salzburg, was appointed 
and consecrated bishop, June 13, 766 or 767. One of his last acts as bishop was 
to visit his entire diocese and to pay a long deferred visit to Carinthia. He 
died Nov. 27, 789. 



444 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

to the Pope against him on this subject, and that the Pope 
replied thereto in a way which showed that he employed the 
term quite in the sense of Boniface; but it does not appear 
that this accusation has had any results. Virgil has always 
held his own. The two antagonists pass for saints, and the 
savants of Bavaria who regard Virgil as an apostle of Carin- 
thia and the neighboring countries, have justified their mem- 
ory of him.] 

CHAPTER IV 

OF THE REALITY OF OUR KNOWLEDGE 

§ 1. Ph. Some one who has not understood the importance 
of having good ideas, and of understanding their agreement 
or disagreement, will think that in reasoning upon them so 
carefully we have been building castles in the air, and that there 
will be in our entire system only the ideal and imaginary. An 
extravagant man, whose imagination is heated, will have the 
advantage of possessing ideas more vivid and in greater num- 
ber, thus he would also have more knowledge. There will be 
as much certitude in the visions of an enthusiast as in the 

Virgil was involved in two controversies with Boniface. First, in regard to 
the validity of an informally administered baptism in which the officiating 
and ignorant priest had mutilated the Latin formula. Boniface said the bap- 
tism was invalid, and must be repeated ; Virgil maintained its validity, and 
on his appeal to Pope Zachary (741-752), was sustained. Second, in regard to 
the "antipodes" here mentioned. Virgil published a philosophical treatise 
maintaining the rotundity of the earth and the antipodes, which Boniface 
regarded as heretical because the view advanced was thought to imply the 
existence of two races of men, one of which did not spring from Adam, was 
therefore free from original sin, and had no need for or share in the work of 
the Redeemer. Pope Zachary, in the letter to Boniface here referred to [cf. 
letters of Boniface, No. 140, in Bibl. Max. Vet. Patr., 27 vols., fol. Lugd., 1677, 
Vol. 13, p. 131-133), characterized as perverse and heretical the doctrine of 
another world and other men under the earth, — " De perversa doctrina, quam 
contra Dominum et animam suam locutus est (quod scilicet alius mundus, 
et alii homines sub terra sint aliusque sol et luna)," etc. ; but Virgil showed 
that his speculations were purely scientific and did not touch the theological 
doctrines of original sin or the unity of the human race. He was accordingly 
acquitted of the charge of heresy, and canonized by Gregory IX. in 1233. Cf. 
Smith and Wace, Diet, of Christian Biog., Vol. 4, pp. 1160, 1211, London, 
1887; Neander, Hist, of the Christ. Relig. and Church, 3, 63; also Bayle, Diet, 
histor. et crit., 2d ed., 1702 (which was, perhaps, Leibnitz's source of infor- 
mation on the subject), Eng. Trans., London, 1738, Vol. 5, p. 493; and for a 
justification of Virgil, cf. " Memoires de Trevoux," Jan. 1708. — Tk, 



en. iv] ON HUMAN UNDERSTANDING 445 

reasonings of a sober rnan ; provided this enthusiast speaks 
consistently; and it will be as true to say that a harpy is not 
a centaur as to say a square is not a circle. § 2. I reply that 
our ideas agree with things. § 3. But the criterion will be 
demanded. — § 4. I reply further in the first place that this 
agreement is manifest as regards the simple ideas of our mind, 
for being unable to form them itself, it must be that they are 
produced by things acting upon the mind; and in the second 
place, § 5. all our complex ideas (those of substances excepted) 
being archetypes which the mind itself has made, not intended 
to be copies of anything nor referred to the existence of any- 
thing as to their originals, they cannot fail to be completely 
conformed to the things necessary to real knowledge. 

Th. Our certitude would be small, or rather nothing, if it 
had no other basis of simple ideas than that which comes from 
the senses. Have you forgotten, sir, how I have shown that 
ideas are originally in our mind, and that indeed our thoughts 
come to us from the depths of our own nature, other creatures 
being unable to have an immediate influence upon the soul. 
Besides the ground of our certitude in regard to Universal 
and eternal truths is in the ideas themselves, independently 
of the senses, just as ideas pure and intelligible do not depend 
on the senses, for example, that of being, unity, identity, etc. 
But the ideas of sensible qualities, as color, savor, etc. (which 
in reality are only phantoms), 1 come to us from the senses, 
i.e. from our confused perceptions. And the basis of the truth 
of contingent and singular things is in the succession which 
causes these phenomena of the senses to be rightly united as 
the intelligible truths demand. 2 That is the difference which 

1 Of. ante, p. 317 (where the term "phantasies," in line 12, rendered hy the 
word "notions," would have been better rendered, perhaps, by "phantasms" 
or "phantoms "), notes 1 and 2, and infra, p. 459. Schaarschmidt translates: 
"Phantasie-Erscheinungen." The term "phantom," or, as it might perhaps 
have been translated, "phantasm," — the Greek ijiwra^a, and the Scholastic 
"phantasma," — signifies here a mental modification given or produced 
through the agency of the senses, but having no corresponding external 
object, i.e. an entirely subjective phenomenon, real as such, but which, since 
it corresponds to no objective external reality, has, to a certain extent, the 
character of a mere appearance. — Tr. 

2 Of. New Essays, Bk. IV., chap. 2, § 14, Th. (2), ante, p. 422, note 1. 
Leibnitz felt, says Schaarschmidt, that we could not be satisfied from a philo- 
sophical point of view with the old definition of truth as consisting in the 
agreement of thought with reality, — Tr, 



446 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

should be made, while that which you here make between 
simple and complex ideas, and ideas complex belonging to sub- 
stances and to accidents, does not appear to me well founded, 
since all intelligible ideas have their archetypes in the eternal 
possibility of things.] 

§ 5. Ph. It is true that our complex ideas need archetypes 
outside the mind only when the question concerns an existing 
substance which must effectively unite outside us these com- 
plex ideas, and the simple ideas of which they are composed. 
The knowledge of mathematical truths is real, although it re- 
volves only upon our ideas, and finds nowhere exact circles. 
But we are assured that existing things will agree with our 
archetypes according as what we suppose therein is found 
existing. § 7. This serves to justify the reality of moral 
things. §8. Nor are Cicero's "Offices" less conformed to 
truth, because no one in the world rules his life exactly 
according to the pattern of a virtuous man such as Cicero has 
painted for us. § 9. But (it will be said) if moral ideas be of 
our invention, what a strange notion shall we have of justice 
and temperance? 

§ 10. I reply that the uncertainty will be only in the lan- 
guage, because what is said is not always understood, or 
always understood in the same way. 

Th. [You might reply also, sir, and much better in my 
opinion, that the ideas of justice and temperance are not of 
our invention, any more than those of the circle or the 
square. I think I have sufficiently shown this.] 

§ 11. Ph. As for the ideas of substances existing outside 
us, our knowledge is real so long as it is conformed to these 
archetypes; and in this respect the mind must not combine 
ideas arbitrarily, so much the more as there are very few sim- 
ple ideas of which we can be certain that they can or cannot 
exist together in nature beyond what appears by sensible 
observations. 

Th. It is, as I have more than once said, because these 
ideas, when reason cannot judge of their compatibility or con- 
nection, are confused, like those of the particular qualities 
of the senses. 

§ 13. Ph. It is well also as regards existing substances not 
to limit ourselves to names or to species supposed to be estab- 



ch. iv] ON HUMAN UNDERSTANDING 447 

lislied by names. This makes me return to discussions we 
have often enough had regarding the definition of man. For 
speaking of an innocent l who has lived forty years without giv- 
ing the least sign of reason, could we not say that he holds 
the middle place between man and beast? It would possibly 
be thought a very bold paradox, or even a falsehood with very 
dangerous consequences. But it seemed to me formerly and 
it seems still to some of my friends whom I cannot disabuse 
as yet (of the idea) that it is only in virtue of a prejudice 
based upon this false supposition that these two names man 
and beast signify distinct species, so well marked by real 
essences in nature that no other species can intervene between 
them, as if all things were thrown into the mould according 
to the precise number of these essences. § 14. When these 
friends are asked what species of animals these innocents are, 
if they are neither men nor beasts, they reply they are innocents, 
and that is sufficient. If asked further what they will become 
in the next world, our friends reply they are not concerned to 
know or inquire. Let them fall or stand to their own master 
(Rom. 14:4), who is good and faithful and disposes of his 
creatures not according to the narrow limits of our particular 
thoughts or opinions, nor does he distinguish them conformably 
to the names and species it has pleased us to invent; let it suffice 
us that those who are capable of instruction will be called to 
render an account of their conduct and will receive their re- 
ward according to the deeds done in their bodies (2 Cor. 5:10). 
§ 15. I shall exhibit to you the rest of their reasonings. The 
question (say they) whether imbeciles must be deprived of a future 
state rests upon two equally false suppositions : first that every 
being having the form and external appearance of man is 
destined to an immortal state after this life; and second that 
everything having a human birth must enjoy this privilege. 
Remove these imaginative ideas, and you will see that such 
questions are ridiculous and groundless. In fact I think we 
shall disallow the first supposition and shall not have the mind 
so buried in matter as to believe that eternal life is due to any 
form of material mass, so that the mass must have feeling 
eternally because moulded upon such a figure. § 16. But the 

1 Locke's word is " changeling," Philos. Works (Bonn's ed.), Vol. 2, p. 176 
sq., and note. — Tr. 



448 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

second supposition comes to the rescue. We shall say that this 
innocent comes from rational parents and that consequently it 
must have a rational soul. I know not by what rule of logic 
we can establish such a consequence, nor how after that we 
should dare to destroy these ill-formed and disfigured produc- 
tions. Oh, they are monsters, it will be said. Very well, so be 
it. But what will this always intractable innocent be? Shall 
a defect in the body make a monster, and not a defect in the 
mind? This is to return to the first supposition, already 
refuted, that the external suffices. A well-formed innocent 
is a man, as we believe; he has a rational soul, although it 
does not appear; but make the ears a little longer and more 
pointed, and the nose a little flatter than usual, then you begin 
to hesitate. Make the face narrower, flatter, and longer; 
there you are all at once decided. And if the head is per- 
fectly that of any animal, it is no doubt a monster ; and this 
is for you a demonstration that it has no rational soul and 
that it should be destroyed. I ask you now where to find the 
just measure and the final limits bearing with them a rational 
soul. There are human foetuses, half beast, half man, others 
three parts of which belong to the one, and one part to the 
other. How determine precisely the lineaments which indicate 
reason? Further, will not this monster be a species midway 
between man and beast? And such is the innocent in question. 
Th. [I am astonished that you return to this question suffi- 
ciently examined by us, and that more than once, and that 
you have not better catechized your friends. If we distin- 
guish the man from the beast by the faculty of reason, there 
is no middle ground, the animal in question must have it or 
not have it; but as this faculty sometimes does not appear, 
we judge of it by indices which are not demonstrative of the 
truth till this reason manifests itself: for we know by the 
experience of those who have lost it and who' at last have re- 
covered its exercise, that its function may be suspended. Birth 
and form furnish presumptions of that which is concealed. 
But the presumption of birth is effaced {eliditur) by a figure 
very different from the human, such as that of the animal was, 
born of a woman of Zealand according to Levinus Lemnius 1 

1 Livin Lemmens — Latin, Levinus Lemnius — 1505-1568, a Dutch physician, 
who was very successful in practice, and had in his time a very great reputa- 



en. v] ON HUMAN UNDERSTANDING 449 

(Book I., Chap. 8), which had a hooked beak, a long and 
round neck, flashing eyes, a pointed tail, and great agility 
at first in running about the room. But you will say that 
there are some monsters or brothers of the Lombards (as the 
physicians formerly called them because it was said that the 
women of Lombardy were subject to this kind of childbirth) 
who approach more and more the human figure. Very well; 
so be it. How then (say you) can the proper limits of the 
figure which is to pass as human be determined? I reply 
that in a conjectural matter there is no precision. And there 
the affair ends. You object that the innocent does not exhibit 
reason, and yet passes as a man, but if it had a monstrous 
figure, it would not be man, and thus you have more regard 
for figure than for reason. But, does this monster exhibit 
reason? Certainly not. You see, then, that it lacks more 
than the innocent. The defect of the exercise of reason is 
often temporal, but it does not cease in those in whom it is 
accompanied by a dog's head. For the rest, if this animal 
with a human figure is not a man, there is no great harm in 
guarding it during the uncertainty as to its fate. And whether 
it has a rational soul or not, God will not have made it for 
nothing, and we may say of the souls of men who live in a 
state always similar to that of early infancy that their fate 
may be the same as that of the souls of those infants who die 
in the cradle. 



CHAPTER V 

OF TRUTH IN GENERAL 

§ 1. Ph. For many centuries the question has been asked, 
What is truth? § 2. Our friends think it is the joining or 
separating of signs according as the things themselves agree 
or disagree among themselves. By the joining or separating 
of signs must be understood what is otherwise called a propo- 
sition. 

tion. Lemnius relates this marvellous occurrence, which he states was reported 
to him by the woman herself, as soon as she had barely recovered, but in which 
there must have been some deception, in his Be miraculis occultis naturse, Bk. 
I., chap. 8, p. 37, Francofurti, 1628, Eng. trans., p. 24, London, 1658. — Tr. 
2g 



450 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

Th. But an epithet does not make a proposition; for example, 
the wise man. But there is a union of two terms. Negation 
also is different from separation; for saying man, and after an 
interval saying wise, is not a denial. Agreement also, or dis- 
agreement is not properly speaking what is expressed by the 
proposition. Two eggs have agreement and two enemies have 
disagreement. The question here concerns an entirely par- 
ticular mode of agreement or disagreement. Thus I think 
this definition fails wholly to explain the point in question. 
But what I find least to my taste in your definition of truth 
is that you seek truth in words. Thus the same sense ex- 
pressed in Latin, German, English, French, will not be the 
same truth, and it will be necessary to say with Hobbes, 1 that 

1 Cf. Leibnitz, Be stilo philos. Nizolii, § 28, ad fin., Gerhardt, 4, 158, Erd- 
maim, 69 b, Duteus, 4, Pt. I., 60, where, after expressing his belief that " Occam 
himself was not more of a Nominalist than Thomas Hobbes now is, who, in 
truth, seems to me more than a Nominalist," Leibnitz continues: " Non con- 
tentus enim cum Nominalibus universalia ad nomina reducere, ipsam rerum 
veritatem ait in nominalibus consistere, ac, quod majus est, pendere ab arbitrio 
humano, quia Veritas pendeat a definitionibus terminorum, definitiones autem 
terminorum ab arbitrio humano." Hobbes in his Leviathan (Morley's Uni- 
versal Library, No. 21), 3d ed., London: Geo. Routledge & Sons, 1887, Pt. 1., 
chap. 4, p. 24, after speaking of " the imposing of ' names,' and the 'connec- 
tion of them,'" says: " When two names are joined together into a conse- 
quence, or affirmation, as thus, ' a man is a living creature ' ... if the latter 
name 'living creature,' signify all that the former name 'man' signifieth, 
then the affirmation, or consequence, is ' true ' ; otherwise ' false.' For ' true ' . 
and 'false' are attributes of speech, and not of things. . . ." And iu the next 
paragraph : " Seeing then that truth consisteth in the right ordering of names 
in our affirmations, a man that seeketh precise truth had need to remember 
what every name he uses stands for, and to place it accordingly." Leibnitz, 
probably, had this or some similar passage in mind, in his references to Hobbes' 
doctrine, and his statement is a possible and seemingly fair interpretation of 
many passages in Hobbes' writings, which passages, however, might be offset 
by others of a different character. Hobbes, nevertheless, seems never to have 
gone beyond his nominalistic position, never, at least, so far as consciously to 
connect his doctrine of truth with the facts of experience and the reality of 
things ; while Leibnitz's doctrine of truth has to a certain extent at least an 
objective reference in affirming an actual or at least possible existence of the 
objects of ideas, cf. ante, pp. 422, note 1, 445, note 2, infra, p. 452, note 1. 

For further exposition of Hobbes' doctrine, cf. G. Croom Robertson, Hobbes, 
pp. 83-90, espec. p. 87 (Philos. Classics), Edinburgh: Win. Blackwood & Sons, 
1886. On the relation of Leibnitz to Hobbes, cf. F. Tonnies, Leibniz und 
Hobbes, in the " Philos. Monatshefte," vol. 23, 1887, 557-573 ; see also, " Mind," 
No. 50, April, 1888, pp. 312-314. For two letters of Leibnitz to Hobbes, cf. 
Gerhardt, Leibniz, philos. Schrift., 1, 82-87, also, 7, 572-574, where the first 
letter is given with an amended text. Leibnitz appended to his The'odicee a 
short piece entitled Reflexions sur Vouvrage que 31. Hobbes a %>ublie en 



en. v] ON HUMAN UNDERSTANDING 451 

truth depends on the good pleasure of men ; which is to speak 
in a very strange manner. You attribute, indeed, truth to God, 
who, you will agree with me (I think), has no need of signs. 
Finally, I have been astonished already more than once at the 
disposition of your friends who are pleased to make essences, 
species, and truths nominal. 

Ph. Do not advance too fast. Under signs they include 
ideas. Thus, truths will be either mental or nominal, accord- 
ing to the species of signs. 

._77i. [We shall then have also literal truths, which maybe 
distinguished as truths upon paper or parchment, of ordinary 
black ink or of printer's ink, if truths must be distinguished 
by signs. It were then better to place truths in the relation 
between the objects of ideas which causes the one to be or not 
to be included in the other. That does not depend upon 
languages, and is common to us with God and the angels; 
and when God manifests a truth to us we shall acquire that 
which is in his understanding, for although there is an infi- 
nite difference between his ideas and ours, as regards perfec- 
tion and extent, it is always true that they agree in the same 
relation. It is, then, in this relation that truth must be placed, 
and we can distinguish between the truths which are inde-' 
pendent of our good pleasure, and between the expressions 
which we invent as seems good to us.] 

§ 3. Ph. It is only too true that men, even in their minds, 
put words in the place of things, especially when the ideas 
are complex and indeterminate. But it is also true as you 
have observed, that then the mind contents itself with the 
indication only of the truth, without for the present under- 
standing it, in the persuasion that it depends upon itself to 
understand it when it will. For the rest, the act which takes 
place in affirming or denying is more easily conceived by re- 
flecting upon what goes on in us, than explained in words. 
Therefore, you do not take it ill that in default of some- 
thing better we have spoken of joining together or of sepa- 
rating. § 8. You will also agree that propositions at least 
may be called verbal, and that, when they are true, they are 

Anglois, de la liberie, cle la necessite et du hasard, cf. Gerhardt, 6, 388-399, 
Ei-dmann, 629-634, Janet, CEuvres philos. de Leibniz, 2, 424-437, Dutens, 1, 
415-429 (in Latin). — Tr. 



452 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

both verbal and also real, for, § 9. falsehood consists in joining 
names otherwise than as their ideas agree or disagree. § 10. 
Words are at least great vehicles of truth. § 11. There is also 
a moral truth, which consists in speaking of things according 
to the persuasion of our mind; there is finally metaphysical 
truth which is the real existence of things in conformity to 
the ideas we have of them. 

Th. [Moral truth is by some called veracity, and metaphysi- 
cal truth is commonly taken by the metaphysicians as an 
attribute of being, but it is an attribute very useless and 
almost void of meaning. Let us content ourselves with seek- 
ing truth in the correspondence of the propositions in the 
mind with the things in question. It is true that I have also 
attributed truth to ideas in saying that ideas are true or false; 
but then I mean, in reality, the truth of propositions affirming 
the possibility of the object of the idea. In the same sense 
we can say also that a being is true, that is to say, the propo- 
sition affirming its actual, or at least, possible existence.] x 



CHAPTER VI 

OF UNIVERSAL PROPOSITIONS, THEIR TRUTH AND CERTITUDE. 

§ 2. Ph. All our knowledge is of general or particular 
truths. We can never make the former, which are the most 
important, well understood, and can ourselves, indeed, very 
rarely comprehend them save as they are conceived and ex- 
pressed by words. 

Th. [I think that other marks also can produce this effect; 
we see it in the characters of the Chinese. A universal char- 

1 Cf. Neio Essays, Bk. II., chap. 32, ante, p. 281, and notes; also Bk. III., 
chap. 3, ante, p. 317, note 3 ; and Bk. IV., chap. 1, ante, pp. 397-8. Locke in the 
first of these passages agrees with the view of Aristotle, De Interpret., 1, 16 a ,. 
12, that truth or falsity is predicahle not of single ideas, hut only of their union 
in judgments or propositions; and Leihnitz in the present passage maintains 
essentially the same doctrine in saying that hy the truth he attributes to ideas 
he means the truth of the propositions affirming the possibility of the objects 
of the ideas. Such " true " or " false " ideas must, then, be regarded simply 
as abbreviated propositions, or as tacitly involving propositions. The idea of 
the decahedron (cf. ante, p. 315, and note 1) is false, although we have its 
nominal definition, because the figure is impossible. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 453 

acteristic 1 very popular and better than theirs might be intro- 
duced if small figures were employed in the place of words, 
which would represent visible things by their lines, and the 
invisible by the visible which accompany them, adding thereto 
certain additional marks suitable to make understood the flex- 
ions and the particles. —This would be of service at first for 
easy communication with distant nations; but if introduced 
also among us without, however, renouncing ordinary writing, 
the employment of this mode of writing would be very useful 
in enriching the imagination, and in giving thoughts less surd 
and verbal than we now have. It is true that the art of draw- 
ing not being known by all, it follows that, excepting the 
books printed in this way (which everybody would soon learn 
to read), everybody could not avail themselves of it otherwise 
than by a method of printing, i.e. having the figures all en- 
graved ready for printing upon paper, and adding thereto 
afterwards with the pen the marks of the flexions or particles. 
But in time everybody would learn the plan in youth, so as 
not to be deprived of the convenience of this figured character, 
which would speak in truth to the eyes, and would be very 
agreeable to the people, just as in fact the peasants already 
have certain almanacs, telling them without words much that 
they ask; and I remember to have seen some satirical impres- 
sions in copper-plate which possessed a somewhat enigmatical 
character in which there were figures significant of themselves, 
mingled with words, 2 while our letters and the Chinese char- 
acters are significant only by the will of men (ex instituto). 

§ 3. Ph. [I think your thoughts will some day be carried 
out, so agreeable and natural appears to me this writing, and 
it seems to be of no little consequence for increasing the per- 
fection of our mind, and rendering our conceptions more real.] 
But to return to general knowledge and its certainty, it will 
be proper to remark that there is a certainty of truth and also 
a certainty of knowledge. When words are so joined in propo- 
sitions that they express exactly the agreement or disagree- 

1 Gf. ante, p. 375, note 1. 

2 Probably something similar to what is now known by the term " Rebus." 
For a brief statement of the development of writing from the picture stage, 
its earliest form, to the alphabetic as we now have it, cf. E. Benj. Andrews, 
Institutes of Gen. Hist., chap. 2, § 13, p. 49, 2d ed. Boston: Silver, Burdett & 
Co., 1888. — Tit. 



454 LEIBNITZ'S CKITIQUE OF LOCKE [bk. iv 

nient as it really is, it is a certainty of truth; and the cer- 
tainty of knowledge consists in perceiving the agreement or 
disagreement of ideas so far as it is expressed in propositions. 
This is what we ordinarily call being certain of a proposition. 

Th. [In fact this last kind of certainty will also suffice with- 
out the use of words, and is nothing else than a perfect knowl- 
edge of the truth ; while the first kind of certainty appears to 
be nothing else than the truth itself.] 

§ 4. Ph. Now as we cannot be assured of the truth of any 
general proposition, unless we know the precise limits of the 
signification of the terms of which it is composed, it will be 
necessary for us to know the essence of each species, which is 
not difficult as regards the simple ideas and the modes. But in 
substances wherein a real essence distinct from the nominal 
is supposed to determine the species, the extent of the gene- 
ral term is very uncertain, because we do not know this real 
essence; and consequently in this sense we cannot be assured 
of any general proposition made upon the basis of these sub- 
stances. But when we suppose the species of substances to 
be nothing else than the reduction of substantial individuals 
into certain sorts, arranged under different general names 
according as they agree with the different abstract ideas which 
we designate by these names, we cannot doubt whether a prop- 
osition, well known as it should be, is true or not. 

Th. [I do not know why you, sir, return again to a point 
sufficiently discussed by us, and which I believe an empty one. 
But, after all, I am very glad of it, because you give me an op- 
portunity very suitable (it seems to me) to disabuse you anew. 
I say then to you that we can be assured, for example, of a 
thousand truths regarding gold, or that body whose internal 
essence makes itself known by the greatest weight known here 
below, or by the greatest ductility, or by other marks. For 
we say that the body of the greatest known ductility is also 
the heaviest of all known bodies. It is true that it is not 
impossible that all which has hitherto been noticed in gold 
will some day be found in two bodies distinguishable by other 
new qualities, and that thus gold would no longer be the low- 
est species, as it has hitherto been regarded provisionally. 
We might also, if the one kind remained rare, and the other 
became common, think it proper to reserve the name of 



ch. vi] ON HUMAN UNDERSTANDING 455 

true gold to the single rare species, in order to retain it in 
use as money by means of new assays which would be suited 
to it. After which we shall not doubt, also, that the internal 
essence of these two species is different; and if indeed the 
definition of an actually existing substance should not be 
fully determined in all respects (as in fact, that of men is not 
as regards the external figure), we should not cease to have 
an infinite number of general propositions upon its subject, 
which would follow from reason and the other qualities which 
we recognize in it. All that we can say regarding these gen- 
eral propositions is, that in case man is taken as the lowest 
species and restricted to the race of Adam, we shall have no 
properties of man such as are named in quarto modo, 1 or may 

1 The term in quarto modo, here used by Leibnitz, refers to a classification 
of propria — ISia, properties — existent in the time of Porphyry, 233-304, though 
not accepted by him, — cf. Kiaayuy-q, chap. 4, 4", 14 (in Aristotle, ed. Berl. 

Acad., Vol. 4, p. 4) : to fie ISiOv Staipouor Terpa^us . . . (18.) reraprov Se e(j>' ov (rvv- 
8eSpa/uijK<= to fxovw (cat ■navrl (cat del, w? T(u a.v9punra to yeAao-TticoV . . . (22.) Taura 5e (cat 

Kvpt'us tSta <pi)o-iv, on (cat avTL(7rpe<j>ei — and due, perhaps, to some one of the old 
Peripatetics, and prevalent in different forms in the Middle Age, according to 
which classification as given by Porphyry there were four classes : 1. Propria 
belonging to one species only, but not to every individual thereof, as gram- 
matical to man ; 2. Propria belonging to every individual of the species, but 
not to this species alone, as biped to man ; 3. Propria belonging to one species 
only and to every individual thereof, but not always, as hoary to man ; 4. Pro- 
pria belonging to one species only, to every individual thereof, always, as 
risibility or risible to man. 

The propria of this fourth class — quartus modus — are, each, of equal 
breadth with its subject, and, though no part of the essence of the species of 
which they are predicated, — man, for example, without theproprium risible, 
still being man, — as a matter of fact belong to every individual of the species 
on all occasions, and to no individual of any other species. Propositions predi- 
cating such propria are judgments in A, according to Archbishop Thomson's 
terminology, of the type "Common Salt is Chloride of Sodium," and are of 
course convertible. 

Propria of this fourth class alone, i.e. propria each of which would be coinci- 
dent with its subject so as to be enouncible in a judgment in A — reciprocal — con- 
stitute the fourth preclicable, and answer to the ISiov of Aristotle and Porphyry, 
and the proprium of Appuleius, Marcianus Capella and Boethius. These 
writers, with the exception of Aristotle, to whom probably the four-fold divis- 
ion of propria was unknown, regard the other three classes, which were pro- 
pria according to the Middle Age schoolmen, as accidents, — accidentia, o-v/xpe- 
iSijicoTa, — a fact which explains the somewhat peculiar language of Leibnitz : 
"We shall have no properties of man such as (of the sort that) are named in 
quarto modo," etc. Leibnitz's thought is this : " In the case of ' man ' " taken 
as the lowest species — species infima — and "limited to Adam's race, there is, 
except provisionally, no such proprium. ' Sole-rational-animal ' would be, 
provisionally, such a proprium, because up till now we know no men whom it 



456 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

be enounced concerning him by a reciprocal or simply conver- 
tible proposition, unless provisionally, as in saying: man is 
the only rational animal. -Taking man as those of our race, 
the provisional consists in the assumption that he is the only 
rational animal of those known to us; for we might some 
day find other animals who would have in common with the 
posterity of men of the present time all that which we have 
hitherto observed in them, but who would have another origin. 
It is as if the so-called Australians should overrun our coun- 
tries : in all likelihood we should then discover some means of 
distinguishing them from ourselves. But in case this should 
not happen, and supposing that God had forbidden this mixt- 
ure of these races, and that Jesus Christ had redeemed ours 
only, it would be necessary to try to make some artificial marks 
in order to distinguish between them. There would doubtless 
be an internal difference, but as it would not make itself recog- 
nizable, we should be reduced to the extrinsic denomination of 
birth alone which we should try to accompany with a durable 
artificial mark that would give an intrinsic denomination, and 
a constant means of distinguishing our race from the others. 
These are all fictions, for we have no need to recur to these 
distinctions, being the only rational animals of this globe. 
Yet these fictions are useful in knowing the natures of ideas, 
substances, and truths general in their character. But if man 
were not taken as the lowest species nor as that of the rational 
animals of the race of Adam, and if, instead of that, he signified 
a genus common to several species, which belonged now to a 
single known race, but which might belong also to others 
distinguishable either by birth or even by their natural marks, 
as, for example, in the case of the supposed Australians; 
then, I say, this genus would have reciprocal propositions, and 
the present definition of man would not be provisional. It is 

would not fit, and know of no other species any of whose individuals it would 
fit. Only provisionally, however, for future discoveries may show, in either 
of these respects, that ' sole-rational-animal,' and ' man ' are not exactly coinci- 
dent concepts." On the whole subject, cf. Prantl, Gesch. d. Logik, Vol. 1, 
pp. 343, 395, 425, 581, 584, 630, 674, 676, 696, Vol. 2, pp. 342-343, Vol. 3, 
p. 102, Vol. 4, p. 241, note 383; Aldrich, Artis Logicss Rudimenta, ed. Mansel, 
Oxford, 1856, pp. 32-34. 

I would add that for much of the material as well as of the language of the 
above note, I am indebted to the kindness of Pres. E. B. Andrews of Brown 
University. — Tr. 



en. vi] ON HUMAN UNDEESTANDING 457 

the same with gold; for suppose that some clay there were two 
kinds of it distinguishable, the one rare and hitherto unknown, 
the other common and perhaps artificial, discovered in the 
course of time; then suppose that the name gold should 
continue for the present species, i.e. for the natural and rare 
gold, in order to preserve by its means the commodity of gold 
money, based upon the rarity of this substance, its definition 
known hitherto by intrinsic denominations would have been 
provisional only, and should be augmented by new marks 
which will be discovered, to distinguish the rare gold or the 
ancient species from the new artificial gold. But if the name 
gold should then remain common to the two species, i.e. if 
by gold you mean a genus of which up to the present time we 
know no subdivision, and which we now take as the lowest 
species (but only provisionally until the subdivision is known) 
and if some day a new species were found, i.e. an artificial 
gold, easy to make, and which might become common ; I say 
that in this sense the definition of this genus should not be 
judged provisional, but perpetual. And indeed, without 
troubling ourselves with the names man or gold, whatever 
name is given to the genus or to the lowest known species, 
and even if none should be given them, what has just been 
said would be always true of ideas, genera or species, and 
species will be defined provisionally only by the definitions of 
genera. But it will always be allowable and reasonable to 
assume, by means of a reciprocal proposition, that there is a 
real internal essence belonging either to the genus or the 
species, which makes itself known ordinarily by external marks. 
I have assumed hitherto that the race does not degenerate or 
change; but if the same race passed into another species, we 
should be so much the more obliged to recur to other marks 
and denominations intrinsic or extrinsic, without confining 
ourselves to the race. 

§ 7. Ph. Complex ideas, which the names we give to the 
species of substances justify, are collections of ideas of certain 
qualities which we have observed coexisting in an unknown sub- 
stratum which we call substance. But we cannot know cer- 
tainly what other qualities coexist necessarily with such com- 
binations, unless we can discover their dependence as regards 
their primary qualities. 



458 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 



Th. I have already remarked before that the same (diffi- 
culty) is found in the ideas of accidents, whose nature is a 
little abstruse, as, for example, are the figures in geometry; 
for when the question concerns, for example, the figure of a 
mirror which collects all the parallel rays into one point as a 
focus, many properties of this mirror may be found before its 
construction is known, but we shall be uncertain about many 
other relations it may have, until we find in it that which 
corresponds to the internal constitution of substances, i.e. the 
construction of this figure of the mirror, which will constitute 
as it were the key to ulterior knowledge.] 

Ph. But if we had known the internal constitution of this 
body, we should have found therein only the dependence 
which the primary, or what you call manifest, qualities may 
have, i.e. you would know what size, figure, and moving force 
depend thereupon ; but we should never know the connection 
which they may have with the secondary or confused qualities, 
i.e. with the sensible qualities, as colors, tastes, etc. 

Th. The fact is, you still assume that these sensible quali- 
ties, or rather the ideas we have of them, do not depend upon 
figure and movement in a natural way, but only upon the 
good pleasure of God, who gives us these ideas. You appear 
to have forgotten, sir, the remonstrance I have more than once 
made to you against this opinion, in order to make you think 
rather that these sensitive ideas depend in detail upon the fig- 
ures and movements, and express them exactly, although we 
cannot distinguish therein this detail in the confusion of 
too great a multitude and minuteness of mechanical actions 
which strike our senses. But if we had reached the internal 
constitution of some bodies, we should see also how they must 
have these qualities, which would themselves be reduced to 
their intelligible reasons ; although it would never be in our 
power to recognize them sensibly in these sensitive ideas 
which are a confused resultant of the actions of bodies upon 
us, as, now that we have the perfect analysis of green into blue 
and yellow, l and have scarcely anything more to ask in regard 
to it save as related to these ingredients, we are, however, 
incapable of analyzing the ideas of blue and yellow in our 

1 Cf. ante, p. 320, note 1 ; also Leibnitz's letter to Th. Burnett, without date, 
but written, according to Gerhardt, in 1699, G., Leibniz, philos. Schrift., 3, 
256. — Tr. 



ch. vi] ON HUMAN UNDEESTANDING 459 

sensitive idea of green, for the very reason that it is a con- 
fused idea. It is much the same as we cannot analyze the 
idea of the teeth of the wheel, i.e. of the cause, in the percep- 
tion of an artificial transparency, which I have noticed among 
the clock-makers, made by the rapid rotation of a cog-wheel, 
which makes the teeth disappear, and an imaginary continu- 
ous transparency appear in their place, composed of the suc- 
cessive appearances of the teeth and their intervals, but in 
which the succession is so rapid that our phantasy cannot dis- 
tinguish it. We find then, indeed, these teeth in the distinct 
notion of this transparency, but not in this confused sensitive 
perception, whose nature is to be and to remain confused; 
otherwise if the confusion ceased (as if the motion were so 
slow that we could observe its parts and their succession) 
this notion, i.e. this phantasm 1 of a transparency would no 
longer exist. And as there is no need of imagining that 
God for his good pleasure gives lis this phantasm, and that 
it is independent of the movement of the teeth of the wheel 
and their intervals, and as, on the contrary, we conceive it 
to be only a confused expression of what takes place in this 
movement, an expression, I say, that consists in the fact that 
these successive things are confounded in an apparent simul- 
taneity : it is thus easy to think that it will be the same as 
regards other sensitive phantasms, of which we have not as yet 
so perfect an analysis, as of colors, tastes, etc. For, to speak 
the truth, they deserve this name phantasms rather than that 
of qualities or even of ideas. And it would suffice us in all 
respects to understand them as well as this artificial trans- 
parency, without its being reasonable or possible to claim 
a further knowledge of them; for to desire these confused 
phantasms to abide, and yet to distinguish therein their in- 
gredients by the phantasy itself, is a contradiction, is a desire 
to have the pleasure of being deceived by an agreeable per- 
spective, and to desire that at the same time the eye see the de- 
ception, which would destroy it. It is a case, in short, where — 

nihilo plus agas 
Quam si des operam, ut cum ratione insanias. 2 

1 Cf. ante, p. 445, note 1. Schaarsckmidt here translates: "Phantasie- 
Erscheinung " ; in line 17 of this page, " Phantasievorstellung " ; in lines 24, 26, 
31, " Erscheinungen." — Tr. 

2 Terence, Eun., 1. 1. 17, 18. — Tr. 



460 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

But it often*happens that men seek nodum in scirpo 1 and make 
difficulties where there are none, by demanding the impossible, 
and afterwards complaining of their impotence and of the 
limits of their light. 

§ 8. Ph. All gold is fixed is a proposition, the truth of which 
we cannot certainly know. For if gold signifies a species of 
things, distinguished by a real essence, which nature has 
given it, we are ignorant what particular substances are of 
this species. Thus, although this maybe gold, we cannot affirm 
it with certainty. If we take gold as a body endowed with a cer- 
tain yellow color, malleable, fusible, heavier than any known 
body, it is not difficult to know what is or is not gold; but 
with all that, no other quality can be affirmed or denied with 
certainty of gold, than that which has a connection with this 
idea, according to a connection or incompatibility which may 
be discovered. 2 Now fixity having no known connection with 
color, weight, and the other simple ideas which I have sup- 
posed to constitute the complex idea we have of gold, it is 
impossible that we can know with certainty the truth of this 
proposition, that all gold is fixed. 

Th. We know almost as certainly that the heaviest of all 
bodies known here below is fixed, as we know certainly that 
it will be light to-morrow. This is because we have tried it a 
hundred thoiisand times ; it is an experimental certainty, and 
of fact, although we do not know the bond which unites the 
fixity with the other qualities of this body. Moreover, it is 
unnecessary to oppose two things which agree and amount to 
the same thing. When I think of a body, which is at the 
same time yellow, fusible, and which resists the cupel, I think 
of a body whose specific essence, although unknown in its 
interior, makes these qualities emanate from its depths, and 
makes itself known confusedly at least by means of them. I 
see nothing wrong in that, nor anything which requires you to 
return so often to the charge in order to attack it. 

§ 10. Ph. It is enough for me now that this knowledge of 
the fixity of the heaviest of bodies is not known to us by the 

i Of. ante, p. 226, note 1. — Tr. 

2 According to the texts of Gerhardt and Erdmann. Jacques and Janet 
read: "Que ce qui a avec cette idee une connexion ou une incompatibilite 
qu'on peut decouvrir " ; i.e. than that which has a discoverable connection 
or incompatibility with this idea. — Tr. 



ch. vi] ON HUMAN UNDERSTANDING 461 

agreement or disagreement of ideas. And I for myself think 
that among the secondary qualities of bodies and the powers 
relating to them there cannot any two be named whose neces- 
sary coexistence or incompatibility can be known with cer- 
tainty, except the qualities which belong to the same sense 
and necessarily exclude one another, as when you can say that 
what is white is not black. 

Th. I believe, however, that you might perhaps find them ; 
for example, every palpable body (or that which may be felt 
by touch) is visible. Every hard body makes a noise when 
struck in the air. The tones of strings or wires are semi-pro- 
portional to the weights which cause their tension. It is true 
that what you ask succeeds only as far as you conceive distinct 
ideas united with confused sensitive ideas. 

§ 11. Ph. It is not always necessary to think that bodies 
have their qualities by themselves independently of anything 
else. A piece of gold, separated from the impression and 
influence of every other body, would immediately lose its 
yellow color and weight; perhaps, also, it would become 
friable and lose its malleability. You know how vegetables 
and animals depend upon the earth, air, and sun; how do you 
know whether the very distant fixed stars have not also an 
influence upon us? 

Th. This is a very excellent remark; and if the contexture 
of certain bodies were known to us, we could not judge wholly 
of their effects without knowing the interior of those which 
touch and traverse them. 

§ 13. Ph. Our judgment, however, may go further than 
our knowledge. For people sedulous in making observations 
can penetrate farther, and by means of certain probabilities 
resulting from an exact observation and by certain hints pur- 
posely put together, often make just conjectures regarding 
that which experience has not yet discovered to them ; but it 
is always only conjecture. 

Th. But if experience justifies these consequences in a con- 
stant manner, do you ' not find that you can acquire certain 
propositions by this means? Certain, I say, at least as those 
which assert, for example, that the heaviest of our bodies is 
fixed and that the one which is after it the heaviest is volatile, 
for it seems to me that the certainty (understanding it as moral 



462 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

or physical), but not the necessity (or metaphysical certainty) of 
these propositions which are learned by experience alone and 
not by analysis and the bond of ideas, is established among 
us and with reason. 1 



CHAPTER VII 



OF PROPOSITIONS CALLED MAXIMS OR AXIOMS 

§ 1. Ph. There is one species of propositions which under 
the name of maxims or axioms pass as principles of science, 
and because they are self-evident, we have been contented to 
call them innate, although no one that I know of has ever tried 
to show the reason and ground of their extreme clearness, 
which forces us, so to speak, to give them our consent. It is 
not, however, useless to enter into this investigation and to 
see whether this great evidence is peculiar to these proposi- 
tions alone, as also to examine how far they contribute to 
our knowledge. 

Th. This investigation is very useful and very important. 
But you must not suppose, sir, that it has been entirely 
neglected. You will find in a hundred places that the Scho- 
lastics have said that these propositions are evident ex ter- 
minis, as soon as the terms are understood, so that they 
were persuaded that the force of conviction was grounded in 
the knowledge of the terms, i.e. in the connection of their 
ideas. But geometers have done very much more: that is 

L ^ 1 Metaphysical and moral or physical certainty differ as the certainty of the 
truths of reason and the truths of fact. The truths of reason ground them- 
selves in the necessities of thought, and their certainty is accordingly absolute. 
The truths of fact, in Leibnitz's view, rest upon the divine choice of the best, 
and have an evidence merely relative and established with the aid of experi- 
ence; their necessity is accordingly only hypothetical. Cf. New Essays, Bk. 
II., chap. 21, § 8, Th., ante, pp. 179-180, and § 13, Th., ante, p. 183. The prin- 
ciple upon which the whole matter depends is the famous distinction of the 
mediaeval scholastics between the understanding and the will of God, a prin- 
ciple to which Leibnitz very often recurs, especially in order to maintain the 
contingency of the world, and to escape from the universal fatalism of 
Spinoza. According to this principle, the understanding of God is the source 
of the necessary truths, and the will of God the source of the contingent truths. 
The distinction, however, does not solve the problem either of the contingency 
of the physical universe or of the moral freedom of man. — Tr. 



en. vii] ON HUMAN UNDERSTANDING 463 

they have undertaken very often to demonstrate them. 1 Pro- 
clus already attributes to Thales of Miletus, one of the 
oldest known geometers, the wish to demonstrate the proposi- 
tions which Euclid has since assumed as evident. 2 -It is said 
that Apollonius has demonstrated other axioms, and Proclus 
has also done so. The late Mr. Eoberval, already eighty 
years old or thereabouts, intended to publish the new ele- 
ments of geometry of which I think I have already spoken to 
you. 3 Perhaps the "New Elements" of Arnauld, which at 
that time made some stir, had contributed thereto. 4 He 
exhibited specimens of them in the Eoyal Academy of Sciences, 
and some found fault that assuming this axiom, if equal mag- 

1 Leibnitz frequently refers, both in the New Essays and elsewhere, to 
the demonstrability of the axioms, and the thought was evidently a favorite 
one with him. It is a weighty thought, too ; for all real advance in specula- 
tive and truly and lastingly constructive thinking rests upon just this " work- 
ing-over of the notions," as Herbart expresses it, this deeper penetration into 
their real meaning and content, and its exposition in the simplest possible 
intelligible forms. — Tr. 

2 Proclus cites Thales of Miletus in prop. XV., theor. VIII., of his In 
primum Euclidis Elementorum lib. Commentarii, ex recog. G. Friedlein, 
p. 299. Thales, c. 624-c. 550 B.C., was the founder of the Greek geometry, astron- 
omy, and philosophy. For his geometry, cf. G. J. Allman, Greek Geometry 
from Thales to Euclid, Dublin, 1889 ; for his philosophy, cf. Zeller, Philos. d. 
Griech., I., 1 [Vol. 1], 180-196, 5th ed., Leipzig, 1892. — Tr". 

3 Cf. ante, p. 107, note 1. — Tr. 

4 The work of Antoine Arnauld, 1612-1694, here referred to is the Nouveaux 
Elemens de Geometric, Paris, 1661, mentioned among the most prominent 
books of that time by Ch. Wolf in his Kurzer Unterricht v. d. vomehmsten 
math. Schrift., Wien, 1763. Arnauld was an excellent mathematician, an able 
philosopher and theologian, a celebrated controversialist, and the indefatigable 
champion and mouthpiece of the Jansenists against the Jesuits. A zealous 
Catholic, he repeatedly tried to convert Leibnitz to that faith. Leibnitz's 
correspondence with him contains important matter regarding his own philos- 
ophy. It was originally edited and published by C. L. Grotefend, Brief wechsel 
z. Leibniz, Arnauld u. d. Landgrafen Ernst v. Hessen-Rheinfels aus d. Hand- 
schriften der Konigl. Bibliothek z. Hannover, Hanover, 1846, and was re- 
printed conformably to Grotefend's text by Janet, CEuvres philos. de Leibniz, 
Vol. 1, pp. 577-691, and, with a new comparison of the original Mss., by Ger- 
hardt, Leibniz, philos. Schrift., Vol. 2, pp. 11-138; cf. also his Einleitung, ib. 
p. 5 sq., and Vol. 1, p. 65, and for Leibnitz's first letter, unanswered, to Ar- 
nauld, ib. 68-82 (Grotefend, op. cit. 137 sq.). 

Arnauld's CEuvres completes, with a life by Larriere, appeared at Paris and 
Lausanne, 1775-1783, 45 vols., Vols. 38-40 containing the philosophical works. 
Of these the most important are : Des vraies et desfausses idees, 1683, directed 
against Malebranche, in which Arnauld develops his doctrine of perception and 
attacks the theory of representative ideas, on which cf. Hamilton's Reid, 
8th ed., Vol. 1, pp. 295-298, Vol. 2, pp. 823 b, 963; Reflexions philos. et theolog. 
sur le nouveau systeme de la nature et de la grace du P. Malebranche, 1685- 



464 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

nitudes are added to equals, equals arise therefrom, he demon- 
strated this other which is considered equally evident: if 
equals are taken from equal magnitudes, equals remain. It was 
said he should have assumed both or demonstrated both. But 
I was not of that opinion, and I believed that it was always 
so much gained to have diminished the number of the axioms. 
Addition is no doubt anterior to subtraction and more simple, 
because the two terms are employed in addition in the same 
way, which is not the case in subtraction. Arnauld did 
the opposite of Roberval. He assumed still more than 
Euclid. As for the maxims, they are sometimes taken as 
established propositions whether evident or not. That may 
be well for beginners whom scrupulousness holds back; but 
when the establishment of science is the question, it is a dif- 
ferent matter. Thus it is that they are often taken in ethics 
and even among the logicians in their topics, in some of which 
there is a good supply, but a part of which contain enough of 
them vague and obscure. For the rest, I said a long time 
since publicly and privately that it is important to demon- 
strate all our secondary axioms, which we ordinarily use, 
by reducing them to the primitive or immediate and indemon- 
strable axioms, which I recently and elsewhere called the 
identicals. 

§ 2. Ph. Knowledge is self-evident when the agreement or 
disagreement of ideas is immediately perceived. § 3. But 
there are truths, not recognized as axioms, which are none 
the less self-evident. Let us see if the four species of agree- 
ment of which we spoke not long since (chap. 1, § 3, and 
chap. 3, § 7), viz. : identity, connection, relation, and real ex- 
istence, furnish us with them. § 4. As for identity or diver- 
sity, we have as many evident propositions, as we have dis- 
tinct ideas, for we can deny both, as in saying man is not a 
horse, red is not blue. Further the statement what is, is, is as 
evident as the statement a man is a man. 

Th. It is true, and I have already remarked that it is as 
evident to say ecthetically in particular A is A, as to say in 

16S6 ; Objections contre Descartes ; and La Logique ou V Art de Tenser, or the 
celebrated Port Royal Logic, 1662, written in conjunction with Nicole (c/. 
infra, p. 530, note 1), the best specimen of the logic of the Cartesian school. 
It has been translated into English most admirably by Prof. Thos. Spencer 



ch. vii] ON HUMAN UNDERSTANDING 465 

general : it is what it is. But to deny the subjects of different 
ideas one of another is not always certain, as I have already 
remarked; as if any one wished to say, the trilateral (or that 
which has three sides) is not a Mangle, because, in fact, tri- 
laterality is not triangularity ; again, if any one had said : the 
pearls of Slusius 1 (of which I spoke to you not long since) 
are not the lines of the cubic parabola, he would have been mis- 
taken, and yet that would have appeared evident to many 
people. The late Mr. Hardy, 2 Conseiller au Chatelet de Paris, 
an excellent geometer and orientalist and well versed in 
the ancient geometers, who has published the commentary 
of Marinus on the Data of Euclid, was so prepossessed with 
the fact that the oblique section of the cone called an ellipse 
is different from the oblique section of the cylinder, that the 
demonstration of Serenus 3 appeared to him paralogistic, and I 
could gain nothing against him by my remonstrances : as he 
was nearly as old as Eoberval, when I saw him, and I was a 
very young man, a difference which could give me very little 
persuasive power as regards him, although in other respects I 
was on very good terms with him. This example may show 
in passing what prepossession may do even in the case of clever 
people, for he was truly prepossessed, and Hardy is spoken of 

1 Cf. ante, p. 387, note 1. — Tr. 

2 Claude Hardy, born near the close of the sixteenth century, died in 1678, 
was a barrister by profession, and became in 1626 " Conseiller au Chatelet de 
Paris." He was acquainted with not less than thirty-six ancient and modern 
languages, and made a profound study of mathematics. Descartes chose him 
as one of his judges in his controversy with Fermat, in 1698, over Fermat's 
De maximis et minimis. Hardy published the Data Euclidis, Greek text, with 
Latin trans., together with the commentary of Marinus, the Neo-Platonist 
(cf. Zeller, Philos. d. Griech., III., 2 [Vol. 6], 833, 3d ed., 1881), who lived in 
the fifth century, and was a disciple and the successor of Proclus (cf. ante, 
p. 108, note 2), at Paris, 1625, 4to. Leibnitz speaks of Hardy as an "homme 
de merite, grand geometre, et grand orientaliste," cf. Dutens, 5, 610.— Tr. 

3 Serenus of Antissa, in the island of Lesbos, a Greek geometer, who lived 
in the fourth century, was the author of two treatises, De Sectione Cylindri 
et Coni, libri duo, which, according to Brunet, appeared, together with the 
Conies of Apollonius of Perga, the Lemmas of Pappus of Alexandria, and the 
commentaries of Eutocius of Ascalonita, at Bonn, 1566, fob, reprinted at Pis- 
toja, 1696, fob, and afterwards edited and published by Halley, Oxford, 1710, 
fol. Hardy could not have seen either of the last two editions, since he died 
in 1678, but possibly he may have been acquainted with that of 1566 ; and, if 
not, then, as Schaarschmidt says, he must refer to Mersenne's Synopsis, 
Paris, 1644, which contains, pp. 276-312, an abridgment of Apollonius and 
Serenus. — Tr. 

2h 



466 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

with esteem in the letters of Descartes. 1 ~But I brought him 
forward only to show how we may be mistaken in denying one 
idea of another, if we have not thoroughly enough examined 
them where it is necessary. 

§ 5. Ph. As regards connection or coexistence, we have very 
few self-evident propositions; there are, however, some, and 
it appears to me that this is a self-evident proposition : two 
bodies cannot be in the same place. 

Th. Many Christians contest the point with you, as I have 
already remarked, and even Aristotle and those who after him 
admit real and exact condensations, reducing one and the same 
entire body into a smaller place than it before filled, and those 
who, as the late Mr. Comenius 2 has done in a little book writ- 
ten expressly for the purpose, claim to overthrow 3 modern 
natural philosophy by the experiment of the air-gun, cannot 
be expected to agree therewith. If you take the body as the 
impenetrable mass, your statement will be true, because it 
will be identical or nearly so; but that the real body is such 
will be denied you. At least it will be said that God could 

1 Schaarschrnidt thinks that Leibnitz here confounded Hardy with Roberval, 
whom he had mentioned just before. Descartes frequently mentions Hardy 
in his letters, cf., for example, Pt. I., epist. Ill, Pt. II., epist. 61, 98, 101, 108, 
Pt. III., epist. 34, 60, 63, etc. ; he also corresponded with him, and doubtless 
valued him highly, as witness his choice of him as arbiter in his controversy 
with Ferniat, but he nowhere in his letters appears expressly to praise him ; 
while he speaks thus of Roberval in Lib. III., epist. 56, ad Fermatium: " qui 
procul dubio inter primarios seculi nostri geometras censeri debet.'-' — Tr. 

2 John Amos Comenius, 1592-1671, the last bishop of the old Moravian and 
Bohemian Brethren, devoted himself chiefly to the reform and regulation of 
public education and instruction, and wrote many works on pedagogy, which 
he collected and published under the title Opera didactica omnia, Amsterdam, 
1657, 4 vols., fol. He also did some work in physical science, publishing his 
Disquisitio de calo?-is et frigoris natura, Amsterdam, 1659, 12mo, which the 
writer in Michaud, Biog. Univ., 9, 345, says is the only one of his physical 
works deserving to be in demand, and his Physicsead lumen divinum refor- 
mats synopsis, Leipsig, 1633, and Amsterdam, 1643, Eng. trans., London, 1651, 
which is, perhaps, the book to which Leibnitz here refers. For Leibnitz's esti- 
mate of a portion of the writings of Comenius, cf. Dutens, 5, 181. For an 
account of his life and work, cf. S. S. Laurie, Comenius. His Life and Educa- 
tional Works, 4th ed. (Pitt Press Series) , Cambridge, Univ. Press, 1893 ; also a 
reprint of the same, with five portraits, a somewhat extended and annotated 
bibliography, and photographic reproductions of pages from early editions of 
Comenius' works, published by C. W. Bardeen, Syracuse, N. Y., 1893. — Tr. 

3 Gerhardt reads "reserver," probably a Ms. or typographical error; Erd- 
mann, Jacques, and Janet read "renverser," which, as the context requires, 
the translation follows. — Tr. 



ch. vii] ON HUMAN UNDERSTANDING 467 

make it otherwise, so that this impenetrability will be ad- 
mitted only as conformed to the, natural order of things which 
God has established and of which experiment assures us, 
although elsewhere it would be necessary to admit that it is 
also very conformable to reason. 

_§ 6. Ph. As for the relations of the modes, mathematicians 
have formed many axioms upon the one relation of equality, 
like that of which you have just spoken, that if equals be 
taken from equals the remainders are equal. But it is not less 
evident, I think, that one and one are equal to two, and that if 
from the five fingers of one hand you take away two and then 
two others from the five fingers of the other hand, the number 
of the fingers remaining will be equal. 

Th. That one and one make two, is not properly a truth, 
but it is the definition of two; although it is true and evident 
that it is the definition of a possible thing. As for the axiom 
of Euclid applied to the fingers of the hand, I willingly admit 
that it is as easy to conceive what you say of the fingers as 
to see it in the case of A and B ; but in order not to do often 
the same thing, you observe it generally, and afterwards it is 
sufficient to make subsumptions. Otherwise, it is as if you 
preferred calculation by particular numbers to universal rules, 
which would be obtaining less than is possible. For it is of 
more account to solve the general problem : to find two num- 
bers whose sum makes a given number, and whose difference 
also makes a given number, than merely to seek two numbers 
whose sum makes ten, and whose difference makes six. For 
if I proceed in this second problem according to the method 
of numerical algebra, mixed with the literal (specieuse), the 
calculation will be as follows : a + b = 10, and a — b = 6 ; 
of which by adding together the right side to the right, and 
the left side to the left, I produce the result, a+b+a—b= 
10 + 6, i.e. (since + b and — b cancel each other) 2 a, = 16 
or a = 8. Subtracting the right side from the right, and the 
left from the left (since to take away a — b is to add — a + b) 
I produce the result a + b — a + b = 10 — 6, i.e. 2 b = 4 or 
6 = 2. Thus, I shall in truth have the a and b I ask for, 
which are 8 and 2, which satisfy the problem, i.e. whose sum 
is 10 and whose difference is 6; but I have not thereby the 
general method for any other numbers, which we might wish 



468 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

or be able to put in the place of 10 or 6, a method which I 
could, however, find with the same facility as these two num- 
bers 8 and 2, by putting x and v in the place of the numbers 
10 and 6. For proceeding the same as before we shall have 
a -\- b ■}- a — b = x + v, i.e. 2a = x + vora = ^x + v, and we 
shall also have a + b — a + b = x — v, i.e. 2b = x — v or 6 = 
^ x — v. This calculation gives this theorem or general canon, 
that when two numbers are required whose sum and differ- 
ence are given, you have only to take as the greater of the 
required numbers, half of the sum made from the given sum 
and difference; and for the less of the required numbers, half 
of the difference between the given sum and difference. You 
see also that I might have dispensed with the letters, if I 
had treated the numbers as letters, i.e. if instead of putting 
2a = 16 and 2 6 = 4, 1 had written 2a = 10 + 6 and 26 = 10 - 6, 
which would have given me a = ^ (10 -+- 6) and 6 = f (10 — 6) . 
Thus, in the particular calculation itself 1 should have had the 
general calculation, taking these symbols 10 and 6 as general 
numbers, as if they were the letters x and v; in order to have 
a truth or method more general, and taking these same charac- 
ters 10 and 6 also for the numbers they ordinarily signify, I 
shall have a sensible example which may serve, indeed, as a 
proof. And as Vieta 1 has substituted letters for numbers for 
the sake of greater generality, I have desired to reintroduce 
the numerical characters, since they are more serviceable 
in algebra (specieuse) even than the letters. I have found this 
of much use in large calculations for avoiding errors and even 

1 Francois Viete, 1540-1603, better known, by tbe Latin form of his name, 
Vieta, was a distinguished French mathematician, who is often regarded as 
the founder of modem algebra, because of his introduction of the general use 
of letters as symbols of undetermined, and therefore general, quantities, thus 
opening up the way for the higher mathematical analysis, afterwards carried 
on by Descartes and others. To him is also due the invention of the different 
simple transformations now used in the solution of equations, such as adding 
to or subtracting from the members of an equation the same quantity, or mul- 
tiplying or dividing them by the same quantity. He first enounced the princi- 
ple of homogeneity or the principle that all the quantities in an equation sbould 
be of one kind, — lines, surfaces, solids, or supersolids, — a principle which, after 
three centuries of controversy, has now been adopted generally by mathemati- 
cians. His various mathematical writings, which, being a man of wealth, he 
printed at his own expense and distributed among the scholars of Europe, 
were collected and edited by F. van Schooten, Professor of Mathematics at 
Leyden, aided by J. Golius and Mersenne, and published under the title of 
Opera mathematica, Leyden, 1646, 1 vol., fol. — Tr. 



ch. vn] ON HUMAN UNDERSTANDING 469 

in the application of proofs, such as the casting away of the 
nines in the midst of the computation without waiting for the 
result, when there are only numbers instead of letters ; which 
may often be when you employ skill in the positions, so that 
the suppositions are found true in the particular case, besides 
the use there is of seeing the connections and orders which 
the letters alone cannot always make the mind discern so well, 
as I have elsewhere shown, after I found that the good char- 
acteristic is one of the greatest aids of the human mind. 
— § 7. Ph. As for real existence which I had counted as the 
fourth species of existence which may be noticed in ideas, it 
can furnish us no axiom, for we have not indeed a demonstra- 
tive knowledge of beings outside us, God alone excepted. 

Th. We can always say that this proposition I exist, is 
of the highest evidence, being a proposition which cannot be 
proved by any other, or rather an immediate truth. And to 
say I think, therefore I am, is not properly to prove existence 
by thought, since to think and to be thinking is the same thing; 
and to say, I am thinking, is already to say, i~ am. You can, 
however, exclude this proposition from the number of the axi- 
oms with some reason, for it is a proposition of fact, based 
upon an immediate experience, and it is not a necessary prop- 
osition, whose necessity is seen in the immediate agreement of 
ideas. * On the contrary, it is only God who sees how these 
two terms, J and existence are united, i.e. why I exist. But if 
the axiom is taken more generally as an immediate or non- 
provable truth, we may say that this proposition, I am, is an 
axiom, and in 'every case we may be assured that it is & primi- 
tive truth, or rather unum ex primis cognitis inter terminos com- 
plexos, i.e. that it is one of the first known statements which 
is understood in the natural order of our knowledge, for it 
may be that a man has never thought expressly of forming 
this proposition, which, however, is innate to him. 

§ 8. Ph. [I have always believed that the axioms have little 
influence upon the other parts of our knowledge. But you 
have disabused me, since you have indeed shown an important 
use of identical propositions. Suffer me, however, sir, to set 
before you still what I have in mind upon this article, for 
your explanations may also serve to make others return from 
their error.] § 8. It is a celebrated rule in the schools that 



470 LEIBNITZ'S CMTIQUE OF LOCKE [ek. iv 

all reasoning comes from things already known and admitted, 
ex praecognitis et praeconcessis. This rule seems to cause these 
maxims to be regarded as truths known to the mind before 
the others, and the other parts of our knowledge as truths 
dependent upon the axioms. § 9. [I think I have shown 
(Book I., chap. 1) that these axioms are not the first known, 
the child knowing much sooner that the rod which I show him 
is not the sugar he has tasted, than all the axioms you please. 
But you have distinguished between particular knowledge or 
experiences of facts and the principles of a universal and 
necessary knowledge (and herein I admit that it is necessary 
to recur to axioms) as also between the natural and accidental 
order]. 

Th. I have also added that in the natural order the state- 
ment, that a thing is what it is, is prior to the statement that 
it is not another; for the question here does not concern the 
history of our discoveries, which is different in different men, 
but the connection and natural order of truths, which is 
always the same. 1 But your remark, viz. : that what the child 
sees is only a fact, deserves still more reflection; for the expe- 
riences of the senses do not give truths absolutely certain (as 
you have often yourself, sir, observed not long since), nor are 
they exempt from all danger of illusion. For if it is allow- 
able to make fictions metaphysically possible, sugar might 
imperceptibly be changed into a rod, in order to punish the 
child who has been naughty, as water is changed into wine 
with us on Christmas eve, if it has been well prepared (mori- 
gene). 2 But in all cases the pain (you will say) that the rod 
inflicts will never be the pleasure the sugar gives. I reply that 
the child will take it into his head as late to make an express 
proposition about this, as to notice this axiom, that you can- 

1 Leibnitz here calls attention to a very important distinction, viz. : the dis- 
tinction between the historical and the natural or logical order of our knowl- 
edge. The genesis of our knowledge, its gradual rise in the course of our lives, 
is always a matter of individual experience, the experience of no two indi- 
viduals being precisely alike ; while the natural or logical order and connec- 
tion of truths, being grounded in reason, is always the same for all. Leibnitz's 
remark further suggests that the origin of a principle or truth is not its 
justification, a common fallacy in much of the investigation of the present 
day, and that the ultimate criteria of truth are philosophical, not historical. 
Of. Bowne, Metaphysics, pp. 13 sq., New York : Harper and Bros., 1882. — Tr. 

2 Duncan, Phllos. WJcs. of Leibnitz, p. 354, translates: "rectified." — Tr.- 



ch. vii] ON HUMAN UNDERSTANDING 471 

not truly say that what is is not at the same time, although 
he can very well perceive the difference of the pleasure and 
the pain, as well as the difference between perceiving and not 
perceiving. 

§ 10. Ph. There are, however, a number of other truths as 
self-evident as these maxims. For example, that one and two 
are equal to three, is as evident a proposition as that axiom 
which states : that the whole is equal to the sum of all its parts. 

Th. You appear to have forgotten, sir, that I have shown 
you more than once that the statement one and tivo is three is 
only the definition of the term three, so that to say that one 
and two is equal to three, is to say that a thing is equal to 
itself. As for this axiom, that the ivhole is equal to the sum of 
all its parts, Euclid makes no express use of it. This axiom 
also needs limitation, for it must be added that these parts 
must not themselves have a common part, for seven and eight 
are parts of twelve, but they make more than twelve. The 
bust and the trunk taken together are more than the man, in 
that the thorax is common to them both. But Euclid says, 
that the whole is greater than its part, a statement which is 
wholly trustworthy. And the statement that the body is 
greater than the trunk, differs from the axiom of Euclid only 
in this, that this axiom is limited to what is exactly necessary : 
but in exemplifying it and clothing the body you make the 
intelligible become also sensible, for the statement that a given 
whole is larger than a given part, is in fact the proposition 
that a whole is larger than its part, but the features of which 
are embellished with some coloring or addition : it is as if he 
who says A B says A. Thus it is not necessary here to oppose 
the axiom and the example as different truths in this regard, 
but to consider the axiom as embodied in the example and 
rendering it true. It is a different matter, if the evidence is 
not observed in the example itself, and when the affirmation 
of the example is a consequence, and not merely a subsump- 
tion of the universal proposition, as may occur indeed in the 
case of the axioms. 

Ph. Our clever author says here: I should like to ask these 
gentlemen who maintain that all other knowledge (not of fact) 
depends upon general principles innate and self-evident, what 
principle they need to prove that two and two are four? for 



472 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

we know (according to him) the truth of this kind of proposi- 
tions without recourse to any proof. What do you say about 
it, sir? 

Th. I say that I was awaiting you there well prepared. 
That two and two are four is not a truth at once immediate, 
supposing that four signifies three and one. We can then 
demonstrate it, and in this way : — 

Definitions. — (1) Two is one and one. 

(2) Three is two and one. 

(3) Four is three and one. 

Axiom. — Putting equal things in their place, the equality remains. 
Demonstration. — 2 and 2 is 2 and 1 and 1 (by def. 1) 2 + 2 

2 and 1 and 1 is 3 and 1 (by def. 2) 2 + 1 + 1 

3 and 1 is 4 (by def. 3) , 3 + 1 

4 

Then (by the axiom) 2 and 2 is 4. Which was to be demonstrated. 

I might, instead of saying that 2 and 2 is 2 and 1 and 1, say 
that 2 and 2 is equal to 2 and 1 and 1, and thus with the 
others. But it may be understood throughout in order to 
shorten the process; and that, in virtue of another axiom 
which states that a thing is equal to itself, or that what is 
the same, is equal. 

Ph. [This demonstration, as little necessary as it is in rela- 
tion to its too well known conclusion, serves to show how 
truths depend on definitions and axioms. Thus I foresee what 
reply you will make to many objections that are made against 
the use of axioms. You object that there will be an innu- 
merable multitude of principles ; but this is when you reckon 
among the principles the corollaries which follow from the 
definitions by the aid of some axiom. And since the defini- 
tions or ideas are innumerable, so also will the principles be 
in this sense, supposing also with you that the undemonstra- 
ble principles are the identical axioms. They become innu- 
merable also by exemplification, but at bottom you can reckon 
A is A and B is B as one and the same principle differently 
clothed. 

Th. Further, this difference of degrees in the evidence 
makes me disagree with your distinguished author that all 



ch. vn] ON HUMAN UNDERSTANDING 473 

these truths called principles and which pass as self-evident, 
because they are so near the indemonstrable primitive ax- 
ioms, are entirely independent and incapable of receiving the 
one from the other any light or proof. For they may always 
be reduced either to axioms, themselves, or to other truths 
nearer the axioms, as this truth, that two and two make four, 
has shown you. And I just told you how Roberval diminished 
the number of Euclid's axioms, by sometimes reducing one to 
another. 

§ 11. Ph. This judicious writer, who has furnished an occa- 
sion for our conferences, agrees that maxims have their use, 
but he believes that it is rather that of closing the mouth of 
the obstinate, than of establishing the sciences. I should be 
very glad, said he, if you would show me some one of these 
sciences built upon these general axioms which cannot be 
shown to be sustained as well without axioms. 

Th. Geometry is, without doubt, one of these sciences. 
Euclid expressly employs axioms in demonstration, and this 
axiom : that tvoo homogeneous magnitudes are equal when one is 
neither larger nor smaller than the other, is the basis of the 
demonstrations of Euclid and Archimedes respecting the size 
of curvilinears. Archimedes employed axioms of which Euclid 
had no need; for example, of two lines, each of which is con- 
cave always on the same side, that which encloses the other is 
the greater. We cannot also dispense with the identical ax- 
ioms in geometry, as, for example, the principle of contradic- 
tion, or the demonstrations which lead to the impossible. 
And as for the other axioms, which are demonstrable, we may 
dispense with them, absolutely speaking, and draw conclu- 
sions immediately from the identicals and from the defini- 
tions; but the prolixity of the demonstrations, and the end- 
less repetitions into which you would then fall, would cause 
a horrible confusion, if it were always necessary to begin ab 
ovo; while by assuming the mean propositions, already 
proved, we easily pass much farther. This assumption of 
truths already known is useful, especially as regards the ax- 
ioms, for they recur so often that geometers are compelled to 
make use of them constantly without citing them ; so that we 
should be mistaken in thinking that they are not there, because 
we do not perhaps always see them quoted in the margin. 



474 LEIBNITZ'S CRITIQUE OE LOCKE [ek. iv 

Ph. But he objects to the example from theology. For the 
knowledge of this holy religion came to us from revelation 
(says our author), and without this aid the maxims would 
never have been able to make us know it. The light comes to 
us then from the things themselves, or immediately from the 
infallible veracity of God. 

Th. It is as if I said, medicine is based upon experience, 
reason then is of no use therein. Christian theology, which 
is the true medicine for souls, is based upon revelation which 
corresponds to experience ; but to make of it a perfect body, 
we must unite therewith natural theology, which is drawn 
from the axioms of eternal reason. Is not this principle 
indeed that veracity is an attribute of God, upon which you 
acknowledge that the certainty of revelation is based, a maxim 
taken from natural theology? 1 

Ph. Our author wishes to distinguish between the means of 
acquiring knowledge and of teaching it, or rather between 
teaching and communicating. After schools had been erected 
and professors established to teach the sciences that others had 
found out, these professors availed themselves of these max- 
ims in order to impress the sciences upon the minds of their 
scholars, and to convince them by means of the axioms of cer- 
tain particular truths ; while the particular truths have served 
the first discoverers in finding the truth without the general 
maxims. 

Th. I wish that this pretended procedure had been justified 
for us by examples of some particular truths. But rightly 
considering things, we shall not find it practised in the estab- 
lishment of the sciences. And if the discoverer finds only a 
particular truth, he is only half a discoverer. If Pythagoras 2 

1 Locke, without discussing its possibility or its method, assumes a special 
source of religion in an immediate revelation of God to the soul of man, and 
rests the truth of this revelation upon the " unerring veracity" of God. Cf. 
Philos. Wks., Vol. 2, p. 209, Bonn's ed. Leibnitz, who elsewhere discusses to 
a certain extent both the possibility and the method of revelation, and admits 
its possibility, and also its actuality, especially as regards those things which 
are beyond the limits of our finite experience, emphasizes the rational element 
in theology by calling attention to the fact that revelation presupposes a nat- 
ural idea of God, philosophically derived and including the attribute of verac- 
ity, to which it may appeal and by which its character and claims to authority 
must be judged. — Tr. 

2 Cf. ante, p. 379, note 1. On his life and philosophy, cf. Zeller, Philos. d. 
Griech., 5th ed., Vol. 1, pp. 296 sq. For his mathematical work, cf. G. J. 



ch. vn] ON HUMAN UNDERSTANDING 475 

had only observed that the triangle whose sides are 3, 4, 5, has 
the property of the equality of the square on the hypothenuse 
with those on the sides (i.e. that 9 + 16 = 25), would he on 
that account have been the discoverer of this great truth which 
includes all right-angled triangles, and which has passed into 
a maxim with the geometers ?- It is true that often an exam- 
ple, seen by chance, serves as the occasion which suggests to a 
clever man the search for general truth, but it is still very 
often no easy matter to find it; besides, this path of discovery 
is not the best nor the most employed by those who proceed in 
an orderly and methodical way, and they make use of it only 
upon the occasions when better methods fall short. In the 
same way, some have thought that Archimedes found the 
quadrature of the parabola by weighing a piece of wood cut 
parabolically, and that this particular experiment caused him 
to discover the general truth; but those who know the pene- 
tration of this great man see clearly that he had no need of 
such an aid. Moreover, if this empirical way of particular 
truths had been the occasion of all the discoveries, it would 
not have been sufficient to give them; and the discoverers 
themselves have been delighted with observing the maxims 
and the general truths if they have been able to attain them, 
otherwise their discoveries would have been very imperfect. 
All that may then be attributed to the schools and to the pro- 
fessors, is that they have collected and arranged the maxims 
and other general truths: and would God they had done so 
still more and with more care and choice, the sciences would 
not be found so scattered and so confused. For the rest I 
admit, that there is often some difference between the method 
we use in teaching the sciences and that which has produced 
their discovery : but this is not the point in question. Some- 
times, as I have already observed, chance has given occasion 
for discovery. If we had noticed these occasions, and had 
preserved the memory of them for posterity (which would 
have been very useful), this detail would have been a very con- 
siderable part of the history of the arts, but it would not have 

Allman, Greek Geometry from Thales to Euclid, Dublin, 1889, and, by tbe 
same author, Pythagorean Geometry, being the mathematical part of the 
article "Pythagoras" in the JEncyclop. Brit., 9th ed., Vol. 20, pp. 146-149 
(Amer. ed.) . — Tr. 



476 LEIBNITZ'S CKITIQUE OF LOCKE [bk. iv 

been proper to make systems of them. Sometimes also dis- 
coverers have proceeded rationally to the truth, but by ex- 
tended circuits. I find that in matters of importance authors 
would have rendered service to the public, if they had been 
willing sincerely to indicate in their writings the traces of 
their experiments ; but if the system of science should be built 
upon that foundation, it would be as if in a finished house you 
wished to preserve all the apparatus which 1 the architect re- 
quired in building it. Good methods of teaching are all such 
that by their means science could certainly have been discov- 
ered; and then if they are not empirical, i.e. if the truths are 
taught by reasons or by proofs drawn from ideas, it will always 
be by axioms, theorems, canons, and such other general propo- 
sitions. The case is different when the truths are aphorisms 
like those of Hippocrates, 2 i.e. truths of fact either general, or 

1 Gerharclt reads " done," manifestly a manuscript or a typographical error. 
Erdmann, Jacques, and Janet read "dont," which the translation follows. — 
Tk. 

2 Hippocrates of Cos, 460-375 B.C., the " Father of Medicine," was the first 
to base the practice of medicine on the observation of nature and the principles 
of an inductive philosophy. Though descended from a family of priest-physi- 
cians, he put aside all its traditions and prejudices, gave himself up to the 
study of the natural history of disease in the living subject, and treated it 
always as subject to natural laws. He placed especial emphasis on sympto- 
mology and dieteties. The two chief modern critical editions of his writings, or 
those ascribed to him, are E. Littre, QSuvres completes d'Hippocrate, 10 vols., 
Paris, 1839-61, and F. Z. Ermerins, Hlppoeratis et aliorum medicorum veterum 
reliquise, 3 vols., Utrecht, 1859-64. The 'A^opurixoi — Aphorisms — are accepted 
as absolutely genuine by Littre, but rejected as spurious by Ermerins. The 
Greek text with French trans, is found in Littre, op. cit., Vol. 4, pp. 396 sq. ; 
with Latin trans., in Ermerins, op. cit., Vol. 1, pp. 397 sq. For an English 
translation, cf. F. Adams, Genuine WJcs. of Hippocrates (Sydenham Soc), 2 
vols., London, 1849, Vol. 2, p. 685. 

In this connection I may add that Professor Schaarschmidt of Bonn Uni- 
versity has kindly informed me that the phrase vv^-wvoto. mivTa cited by Leibnitz 
from Hippocrates, cf. ante, p. 48 (ad fin.) is to be found in the Ue P l rpo^, § 23, 
Littre, (Euvres d'Hippocrate, Vol. 9, p. 106, where it runs thus: Hvppoia /nia, 
£ vfj-nvoia. jxia, f u^jraSea iv6.vra • k.t.a. Professor Schaarschinidt thinks that Leib- 
nitz probably read : i^v^-wota ttclvto., — conspirantia omnia, — omitting fiCa and 
gv/xira.eea, and took ^vfiirvoia for an adjective, while it is in the text a substan- 
tive meaning concordance, — conspiratio, — a usage which sometimes occurs, 
cf. Stephanus, Thesau. Ling. Grsec, Vol. 3, p. 416, C; or that he quoted 
from memory, as he often does. Sii^i/ovs — conspirans — as an epithet of the 
universe occurs in Plutarch, De fato, 2, 574, E: to ^Vei SiotKelaBai. rovSe rhv 

KoafLov, <TViJ.nvovv, Ka\ o-vixna8ri, avrbv airiZ ovra, i.e. "that the World is governed 

by Nature, and that it conspires, consents, and is compatible with itself." 
Plutarch's Morals, Eng. trans., by several hands, corrected and revised by 
W. W. Goodwin, Ph.D., Vol. 5, p. 308, Boston : Little, Brown & Co., 1870. — Tit, 



ch. vii] ON HUMAN UNDERSTANDING 477 

at least true most frequently, learned by observation or based 
on experience, and for which there are no reasons immedi- 
ately convincing. But the question here is not about this, 
for these truths are not known by the connection of ideas. 
- Ph. Here is the manner in which our ingenious author con- 
ceives that the need of maxims has been introduced. The 
schools having established disputation as the touchstone of the 
ability of people, they adjudged the victory to the one who 
holds the field of battle and speaks the last word. But in 
order to furnish means of convincing the obstinate, it was 
necessary to establish maxims. 

Th. The schools of philosophy had done better, no doubt, 
to unite practice with theory, as do the schools of medicine, 
chemistry, and mathematics ; and to give the prize to the one 
who had done the best, especially in ethics, rather than to the 
one who had spoken the best. Yet as there are matters in 
which discourse itself is an effect and sometimes the sole 
effect and masterpiece which can make known the ability of 
a man, as in metaphysical matters, we have had reason on 
some occasions to judge of the ability of people by their suc- 
cess in the conferences. We know, indeed, that at the begin- 
ning of the Reformation the Protestants challenged their 
adversaries to come to colloquies and discussions, and some- 
times upon the success of these discussions the public con- 
cluded for the reform. We know, also, how much the art of 
speaking and of giving birth and force to reasons, and, if it 
may be so called, the art of discussion, can accomplish in a 
council of state and of war, a court of justice, a medical con- 
sultation, and even in a conversation. And we are obliged to 
recur to this means and to content ourselves with words 
instead of acts on those occasions, for this very reason that 
the question then concerns an event or future fact where it 
would be too late to learn the truth by the effect. Thus the 
art of discussion or of contending by reasons (whereby I here 
understand the quotation of authorities and examples) is very 
great and very important ; but unfortunately it is very badly 
managed, and for this reason also often reaches no conclusion 
or a bad one. It is for this reason that I have more than 
once intended to remark upon the colloquies of theologians, 
accounts of whom we have, in order to show the defects which 



478 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

may be noticed in them and the remedies that might be em- 
ployed therefor. In consultations upon business, if those who 
have the most power have not a very solid mind, authority or 
eloquence prevail ordinarily, although they are banded against 
the truth. In a word, the art of conferring and discussing 
would need to be entirely remodelled. As for the advantage 
of the one who has the last word, it is almost wholly in free 
conversations ; for in councils suffrages or votes go by order, 
whether they begin or finish with the last in rank. It is true 
that it ordinarily belongs to the president to begin and end, 
i.e. to propose and decide; but he decides according to the 
plurality of the votes. In academic discussions it is the 
respondent or maintainant (of the thesis) who speaks last, and 
the field of battle abides with him, almost always by an 
established custom. It is a question of testing him, not of 
confounding him; otherwise it would be treating him as an 
enemy. In reality, there is almost no question of truth on 
these occasions : indeed, opposite theses are maintained at 
different times in the same chair. The hall of the Sorbonne 
was shown to Casaubon, 1 and they said to him: this is the 
place where they have disputed for so many centuries; he 
replied, to what conclusion have they come? 

Ph. The wish was, however, to prevent the dispute from 
going on to infinity, and to furnish means of deciding between 
two equally expert combatants, in order that the dispute 
enter not upon an infinite series of syllogisms. This means 
was the introduction of certain general propositions, the 
larger part self-evident, and which being of such a nature as 
to be received by all men with entire consent, were to be 
regarded as general measures of truth, and to hold the place of 
principles (when the disputants had posited no others), beyond 
which none could go, and to which both sides were obliged to 
hold. Thus these maxims having received the name of prin- 
ciples which could be denied in the dispute, and which ended 
the question, they were taken erroneously (according to my 
author) as the sources of knowledge and the foundations of 
the sciences. 

1 Isaac Casaubon , 1559-1614, a great classical scholar and editor, who had 
the reputation of being, next to Scaliger, the most learned man of his age. 
Leibnitz also relates this anecdote in his letter to Thomas Burnett, Feb. 1-11, 
1697, Gerhardt, 3, 192, Dutens, 6, 245. — Tr. 



ch. vii] ON HUMAN UNDERSTANDING 479 

Th. Would to God we had made use of them in this way 
iu the discussions, there would be nothing to say in reply, for 
we should decide something. And what better thing could 
we do than to reduce controversy, i.e. contested truths to 
truths evident and incontestable? would not that be to estab- 
lish them in a demonstrative fashion? And who can doubt 
that these principles, which would end disputes by establish- 
ing truth, would not be at the same time sources of knowledge? 
Forj provided the reasoning is good, it matters not whether 
it is carried on silently in one's study, or exposed for sale 
publicly in a professor's chair. And even if these principles 
were assumptions rather than axioms, taking the assumptions 
not as Euclid, but as Aristotle, i.e. as suppositions which 
must be admitted while waiting opportunity to prove them, 
these principles would always have this use, that by means 
of them all the other questions would be reduced to a small 
number of propositions. Thus I am the most surprised of 
anybody to see a praiseworthy thing blamed by I know not 
what prepossession, to which we clearly see by the example 
of your author the most clever men are susceptible through 
want of attention. Unfortunately they do an entirely differ- 
ent thing in academic disputes. Instead of establishing gen- 
eral axioms, they do all they can to weaken them by vain and 
little understood distinctions, and it pleases them to employ 
certain philosophical rules, of which there are large books 
completely full, but which are little certain and little deter- 
mined and which they have the pleasure of eluding while dis- 
tinguishing them. This is not the way to end the disputes, 
but to render them infinite, and finally to wear out the 
adversary. It is as if we put him in a dark place, where we 
strike at random and no one can judge the blows. This 
invention is admirable for the maintainants (Respondentes) 
who are engaged in maintaining certain theses. It is a buck- 
ler of Vulcan which renders them invulnerable; it is Orci 
galea, Pluto's helmet, which renders them invisible. They 
must be very unskilful or very unfortunate if they can be 
caught with that. It is true there are some rules which have 
exceptions, especially in questions into which many circum- 
stances enter, as in jurisprudence. But to render their use 
sure these exceptions must be determined in number and 



480 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

sense so far as possible; and then it may be that the excep- 
tion itself has its sub-exceptions, i.e. its replications, and that 
the replication has its duplicatio7is, etc., but at the end of the 
reckoning, all these exceptions and sub-exceptions, clearly de- 
termined, and joined with the rule, must achieve universality. 
Of this jurisprudence furnishes very remarkable examples. 
But if these kinds of rules, loaded with exceptions and sub- 
exceptions, should enter into academic disputes, it would 
always be necessary to dispute pen in hand, holding as a 
protocol what is said by both sides. And this would be more 
necessary elsewhere, in disputing constantly pro forma by 
means of many syllogisms, mixed from time to time with dis- 
tinctions, which the best memory in the world must confound. 
But we are not kept from giving ourselves this trouble, from 
pushing sufficiently the formal syllogisms and from registering 
them, in order to discover the truth when it is without recom- 
pense, and we should not indeed succeed therein, if we wished, 
unless the distinctions are excluded or better regulated. 

Ph. It is, however, true, as our author observes, that the 
scholastic method having been introduced also into conversa- 
tions outside the schools, in order to shut the mouths of 
cavillers, has produced a bad effect. For, provided we have 
mediate ideas, we may have the connection without the aid of 
the maxims and before they have been produced, and that 
would be sufficient for sincere and tractable people. But the 
method of the schools having authorized and encouraged men 
in opposing and resisting evident truths until they are reduced 
to contradict themselves or to fight established principles, it 
is no wonder that in ordinary conversation they are not 
ashamed to do what in the schools is a subject of glory and 
counted a virtue. The author adds that reasonable people, 
among the rest of the world, who are not yet corrupted by 
education, will find it very difficult to believe that such a 
method has ever been followed by persons who make a pro- 
fession of loving truth, and who pass their lives in studying 
religion or nature. I shall not inquire here (says he) how 
this method of instructing is fitted to turn away the minds of 
young people from the love of and sincere search for the 
truth, or rather to make them doubt if there really is any 
truth in the world, or at least any which deserves their 



ch. vii] ON HUMAN UNDERSTANDING 481 

adherence. But what I strongly think (he adds) is this, that 
excepting those places which have admitted the Peripatetic 
philosophy into their schools, where it has reigned many cen- 
turies without teaching the world anything but the art of dis- 
putation, these maxims are nowhere regarded as the foundations 
of the sciences nor as important aids to advancement in the 
knowledge of things. 

Th. Your clever author will have it that the schools alone 
have been led to form maxims; but it is the general and very 
rational instinct of the human race. You can infer this from 
the proverbs which are in use among all nations, and which 
are usually only maxims which the public acknowledge. But 
when persons of judgment make a statement which appears to 
us contrary to the truth, we must do them the justice to sus- 
pect that there is a greater defect in their expressions than 
in their sentiments : a procedure confirmed here in our author, 
of whose motive animating him against the maxims, I begin 
to catch a glimpse. Cavilling, as well as the desire to be con- 
vinced in order to yield, exists as really in ordinary discourse, 
where there is no question of exercise, as in the schools ; else- 
where most frequently they have the better grace to suppress 
the majors which are understood, and to be contented with 
enthymemes, and indeed without forming premises it is suffi- 
cient often to use the simple meclius terminus or mediate idea, 
the mind understanding sufficiently its connection without ex- 
pressing it. 1 And this is satisfactory when this bond is incon- 
testable ; but you, sir, will also agree with me that often we 
go too fast in assumption, and that paralogisms arise so that 
it would very often be better to have regard for certainty, 
in expressing ourselves, than to prefer thereto brevity and 
elegance. But the prejudice of your author against maxims 

1 Ordinarily in argumentation we omit one of the premises, usually the 
major, as easily understood and too clearly manifest to require statement. 
Sometimes, but less commonly, we omit the minor premise, and occasionally 
the conclusion, as in epigrams and other forms of wit, the whole point of 
which very often consists in making apparent the unexpressed truth. Leib- 
nitz emphasizes the sufficiency of the middle term — medius terminus — or 
mediate idea, because through it, the common term in the premises expressing 
the particular reason in the given case, the conclusion is reached, whence the 
middle term is sometimes called the argument. The mind having grasped the 
particular reason expressed in this term, can easily supply the rest of the argu- 
ment, and, if necessary, state it in due syllogistic form. — Tr. 
2 i 



482 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

made him reject altogether their utility for the establishment 
of the truth, and goes as far as to make them accomplices with 
disorders in conversation. It is true that young people 
accustomed to academic exercises in which they are occupied 
a little too much with exercise and not enough in drawing 
from the exercise the greatest fruit it should have, viz. : 
knowledge, have some difficulty in emancipating themselves 
therefrom in the world. And one of their cavillings is not to 
wish to yield themselves to the truth save when it has been 
rendered entirely palpable to them, though sincerity and 
indeed civility should compel them not to wait for these ex- 
tremes, which make them disagreeable and give a bad opinion of 
them. It must also be admitted that it is a vice with which 
men of letters are often found infected. But the fault is not 
in wishing to reduce truths to maxims, but in wishing to do 
it unseasonably and needlessly, for the human mind sees much 
at a glance, and it is to restrain it that we wish to compel it 
to stop at every step it takes and to express all that it thinks. 
It is precisely as if when making his account with a merchant 
or host one should compel him to reckon the whole with the 
fingers in order to be more certain of it. And to make that 
demand he must be either stupid or capricious. In fact, 
sometimes we find that Petronius had reason for saying 
adolescentes in scholis stultissimos fieri, 1 that young people 
sometimes become stupid and even harebrained in places, 
which ought to be schools of wisdom; corruptio optimi pessima.' 2 
But still oftener they become vain, blundering, and confused, 
whimsical, troublesome, and that often depends on the dis- 
position of their masters. For the rest, I find that there are 
far greater faults in conversation than that of demanding too 
much clearness. For usually we fall into the opposite vice 
and neither give nor ask for enough of it. If the one is 
troublesome, the other is hurtful and dangerous. 

1 Petronius, Satyricon, chap. 1: "Et ideo ego adolescentulos existimo in 
scholis stultissimos fieri, quia nihil ex iis, quas in usu hahenius, aut audiunt, 
aut vident," etc. — Tr. 

2 The phrase is not found in any classical author. It was perhaps suggested 

by Aristotle, Politics, A, 2, 1289 a , 39: avdyicri yap rr)V fJ.ev T^js irpuTrjs /ecu 0eiOT<xT7]s 

jVoAiretas] napeicBaaLv nlvai xeiptVTrjj/, thus translated by Jowett, The Politics 
of Aristotle, Vol. 1, p. 109, Oxford : Clarendon Press, 1885 : " That which is the 
perversion of the first and most divine [government] is necessarily the worst." 
— Tr. 



ch. vii] ON HUMAN UNDERSTANDING 483 

§ 12. Ph. The use of maxims is sometimes also, when 
attached to false notions, vague and uncertain; for then the 
maxims serve to confirm us in our errors, and even to prove 
contradictions. For example, he who with Descartes 1 forms 
an idea of what he calls body, as of a thing which is nothing 
but extension, may demonstrate easily by this maxim what is, 
is, that there is no vacuum, i.e. space without body. For he 
knows his own idea, he knows that it is what it is and not 
another idea; thus extension, body, and space being with him 
three words signifying one and the same thing, it is also as 
true for him to say, that space is body, as to say that body is 
body. § 13. But another for whom body signifies a solid 
extension, will conclude in the same way that to say : that 
space is not a body is as certain as any proposition we can 
prove by this maxim : it is impossible for a thing to be and not 
to be at the same time. 

Th. The bad use of maxims should not cause their general 
use to be censured ; all truths are liable to this disadvantage, 
that, by uniting them with falsehoods, false or even contradic- 
tory conclusions may be drawn. And in this example there 
is but little need of these identical axioms to which is im- 
puted the cause of the error and contradiction. This would 
be seen if the argument of those who concluded from their 
definitions, that space is body, or that space is not body, 
were reduced to form. There is, indeed, something exces- 
sive in this inference : body is extended and solid, then exten- 
sion, i.e. the extended is not body, and extension is not a 
corporeal thing; for I have already remarked that there are 
superfluous expressions of ideas, or those which do not mul- 
tiply things, as if some one said, by triquetrum I mean a 
trilateral triangle, and concluded therefrom that every "trilat- 
eral is not a triangle. Thus a Cartesian might say that the 
idea of a solid extension is of this same nature, i.e. that it is 
superfluous; as in reality, taking extension as something sub- 
stantial, every extension will be solid, or rather every exten- 
sion will be corporeal. As for the vacuum, a Cartesian will be 
right in concluding from his idea or form of idea that there is 
none, supposing his idea to be valid; but another will not be 

1 Of. Princip. Philos., II., §§ 1, 4, 11, Veitch's trans., pp. 232, 237, 8th ed., 
Edinburgh, 1881. — Tr. 



484 LEIBNITZ'S CRITIQUE OE LOCKE [be. iv 

right in concluding at once from his form that there may be a 
vacuum, as in reality, although I am not for the Cartesian 
view, I nevertheless think there is no vacuum, 1 and I find 
that in this example a worse use is made of ideas than of 
maxims. 

§ 15. Ph. It seems at least that from such use as you would 
make of maxims in verbal propositions they cannot give us 
the least knowledge of substances existing outside us. 

Th. I am altogether of another opinion. For example, this 
maxim that nature proceeds by the shortest paths, or at least 
by the most definite, suffices alone to give a reason for nearly 
the whole of optics, catoptric and dioptric, i.e. of what takes 
place outside us in the action of light, as I have formerly 
shown 2 and Molyneux has strongly approved in his Dioptric, 
which is a very excellent book. 3 

Ph. It is maintained, however, that when use is made of 
identical principles to prove propositions in which there are 
words signifying complex ideas as man or virtue, their use is 
extremely dangerous, and invites men to regard or receive 
falsehood as manifest truth. And this is because men think 
that when the same terms are retained the propositions re- 
volve about the same things, although the ideas which these 
terms signify are different ; so that men taking the words for 
the things, as they usually do, these maxims commonly serve 
to prove contradictory propositions. 

Th. How unjust to blame the poor maxims for that which 
should be imputed to the bad use of terms and to their equiv- 
ocations. By the same reasoning you will blame the syllo- 
gisms because they conclude badly when the terms are equiv- 
ocal. But the syllogism is innocent, because in reality there 
are then four terms contrary to the rules of the syllogism. 
By the same reasoning you would also blame the calculations 
of arithmeticians, or of algebraists, because by putting Xfor V 
or by taking a for b by inadvertence, they draw therefrom 
false and contradictory conclusions. 

1 Cf. ante, p. 16, and New Essays, Bk. II., chap. 4, ante, pp. 125-127; also 
Descartes, Princip. Philos., II., §§ 16 sq., Veitch's trans., pp. 241 sq. — Te. 

2 Leibnitz probably refers to bis article Unicum optica} catoptricse et di- 
optricse principium, published in the " Acta Erud. Lips.," June, 1682, pp. 185- 
190, and found in Dutens, 3, 145-150. — Te. 

3 Cf. ante, p. 138, note 1. Molyneux's Dioptrica nova was for a long time 
the chief work on Optics. — Te. 



ch. vii] ON HUMAN UNDERSTANDING 485 

§ 19. Ph. I should think at least that maxims are of little 
use when we have clear and distinct ideas; and others will 
have it indeed that then they are absolutely of no use, and 
maintain that any one who in these instances cannot discern 
truth and falsehood without these kinds of maxims, will not 
be able to do so by their agency ; and our author (§§ 16, 17) 
shows indeed that they are of no use in deciding whether such 
a one is a man or not. 

Th. If the truths are very simple and evident, and closely 
approaching the identicals and the definitions, there is but 
little need of expressly employing maxims to draw from 
them these truths, for the mind virtually employs them and 
makes its conclusion all at once without intermediate ideas. 
But without axioms and theorems already known, mathema- 
ticians would have much trouble in advancing; for in long 
processes of reasoning (consequences), it is well to stop from 
time to time, and to set up, as it were, military columns in 
the midst of the road, which will serve furthermore to indi- 
cate it to others. Otherwise these long roads will be too 
inconvenient, and will appear even confused and obscure, 
while we are unable to discern anything, or to point out what 
place we are in. It is like going to sea without a compass in 
a dark night, seeing neither bottom, shore, nor stars ; it is like 
travelling in vast moors in which there are neither trees nor 
hills nor streams; it is like a linked chain destined for the 
measurement of lengths, in which there are some hundreds of 
links, perfectly alike, without a distinction of a bead, or of 
coarser grains or of larger links or other divisions which 
might indicate the feet, fathoms, perches, etc. The mind 
which loves unity in multiplicity then joins together some of 
the consequences to form from them mediate conclusions, and 
this is the use of maxims and theorems. By this means there 
is more pleasure, more light, more memory, more application 
and less repetition. If some analyst in calculating should 
choose not to assume these two geometrical maxims, that the 
square on the hypothenuse is equal to the two squares of the . 
sides about the right angle, and that the corresponding sides 
of similar triangles are proportional, thinking that, because 
we have the demonstration of these two theorems by the con- 
nection of the ideas they contain, he can pass them by easily 



486 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

by putting the ideas themselves in their place, he will find 
himself far removed from his reckoning. But that you may 
not think, sir, that the proper use of these maxims is confined 
to the limits of the mathematical sciences alone, you will find 
that its use is not less in jurisprudence, and one of the prin- 
cipal means of rendering it easier, and of looking at its vast 
ocean as upon a geographical map, is to reduce a multitude of 
particular decisions to more general principles. For exam- 
ple, you will find that a multitude of laws, of Digests, of 
actions or exceptions, of those which are called in factum, 1 
depend on this maxim, ne quis alterius damno fiat locupletior, 2 
let no one profit by the injury which might happen to an- 
other, a principle which should, however, be expressed with a 
little more precision. It is true that there is a great distinc- 
tion to be made between the rules of law. I speak of good 
ones, and not of certain brocards (brocardica) s introduced by 
the doctors which are vague and obscure ; ^although these rules 
also might often become good and useful, if reformed, while 
with their infinite distinctions {cum suis fallentiis) they serve 
only to confuse. Now good rules are either aphorisms or 
maxims, and under maxims I include both axioms and theo- 
rems. If these are aphorisms which are formed by induction 
and observation, and not by reason a priori and which clever 
people have made after a review of established law, this text 
of the jurisconsult Paulus in the title of the Digests, which 
of the rules of law, has place : non ex regula jus sumi, 



1 Cf. Digest., Lib. XLIV., Tit. VII., 25, Ulpianus, lib. singul. Regularum: 
"§ 1. — In factum actio dicitur, qualis est (exempli gratia) actio quae datur 
patrono adversus libertum, a quo contra edictum praetoris in jus vocatus 
est." — Tr. 

2 For a similar expression, cf. Digest., Lib. L:, Tit. XVII., 206, Pomponius, 
lib. 9, ex variis Lectionibus : " Jure naturae sequum est, neminem curn alterius 
detrimento et injuria fieri locupletiorem " ; Digest., Lib. XII., Tit. VI., 14; 
also Lib. XXIII., Tit. Ill, 6, Pomponius, lib. 14 ad Sabinum, § 2: ". . . quia 
bono et aequo non conveniat, aut lucrari aliquem cum damno alterius, aut 
damnum sentire per alterius lucrum " ; Lib. XIV., Tit. III., 17, § 4, ad fin. — Tr. 

3 Cf. Letter 11, to Kestner, Jan. 30, 1711, § 2 (Duteus, 4, Pt. III., 264, also 
Kortbolt, Leibnit. epist. ad diversos, Lips. 1734-1742, 3, 251): " Brocardica 
quae vocant, vel sunt ipsa solida juris principia, vel regulse, quaedam topicae : 
priora necessaria sunt: posteriores utiles forent, si satis examinatae, explica- 
taeque haberentur : pertinent enim fere ad facti quaestionem, artemque conji- 
ciendi, ad quam refero etiam interpretandi artificium." Cf. also Leibnitz's 
Nova methodus discendse docendxque jurisprudentiee, Pt. II., § 25, Dutens, 4, 
Pt. III., 188-189.— Tr. 



ch. vn] ON HUMAN UNDERSTANDING 487 

seel ex jure quod est regulam fieri, 1 i. e. we draw rules from a 
law already known, in order the better to remember them, but 
we do not establish the law upon these rules. But there are 
fundamental maxims constituting the law itself and forming 
actions, exceptions, replications, etc., which, when they are 
taught by pure reason, and do not arise from the arbitrary 
power of the state, constitute natural law; and such is the 
rule of which I have just spoken, which forbids tortious 
profit. There are also rules whose exceptions are rare, and 
which consequently pass as universal. Such is the rule of the 
Institutes of the Emperor Justinian in § 2 of the title Actions, 
which declares that when the question concerns corporeal 
things, the actor does not possess, except in a single case 
which the emperor states is indicated in the Digests; but 
he leaves us to search for it. It is true that some read 
instead of sane uno casu, sane non uno ; 2 and from one case 
you can sometimes make many. Among the physicians the 
late Mr. Earner, 3 who, in giving us his Prodromus, made us 
hope for a new Sennertus, 4 or system of medicine accommodated 

1 Cf. Digest., Lib. L., Tit. XVII., 1. Paulus [lib. 16 ad Plautium] : " Regula 
est, quae rem, quse est, breviter enarrat. Non ut ex regula jus sumatur, sed 
ex jure, quod est, regula fiat." Gerhardt's text omits the name Paulus, and 
his footnote states that there is a gap in the Ms. — Tk. 

2 Cf. Sandars, Inst, of Justinian, Lib. IV., Tit. VI., De actionibus, § 2, ad 
fin. (p. 431, 8th ed., London, 1888): "Quod genus actionis in controversiis 
rerum corporalium proditum non est, nam in his is agit qui non possidet : ei 
vero qui possidet, non est actio prodita per quam neget rem actoris esse. Sane 
uno casu, qui possidet, nihilominus actoris partes obtinet, sicut in latioribus 
Digestorum libris opportunius apparebit." The reading "sane uno casu" is 
adopted and followed by the modern editors. The references to the Digests 
are, according to Sandars, Lib. VIII., 5, 2, Lib. XXXIX., 1, 15, ed. Mommsen, 
Berlin : Weidmann, 1870, pp. 267, 378. — Tk. 

3 Jacob Barner, 1611-1686, a German physician, was professor of chemistry 
at Padua, and of philosophy and medicine at Leipzig, and the author or com- 
piler of a large number of works which give a sufficiently faithful account of 
the medicine and especially the chemistry of his time, wholly occupied as it 
was in the chimerical search for the philosopher's stone. His Prodromus Sen- 
nerti novi, Augustas Vindelicorum, 1674, 4to, was published as the prospectus 
of a proposed, but never completed, work, which, like that of Sennert, should 
cover the history of medicine from the earliest times to his own day. — Tr. 

4 Daniel Sennert, 1572-1637, a celebrated German physician, was professor 
of medicine in the University of Wittemberg from 1602-1637, and introduced 
into its curriculum the teaching of chemistry, in spite of strong and continued 
opposition from those who thought it useless. He disputed the doctrine of the 
soul held by the Schoolmen, and by maintaining the immateriality of the souls 
of animals raised against himself many adversaries, among whom was Honora- 



488 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

to the new discoveries or views, advances the opinion that the 
method which physicians ordinarily observe in their systems 
of practice is to explain the art of healing by treating of one 
disease after another following the order of the parts of the 
body human or other, without having given universal precepts 
of practice common to many diseases and symptoms, and that 
this involves them in an infinite number of repetitions; so 
that we might suppress, in his view, three-quarters of Senner- 
tus, and abridge the science infinitely by universal propositions, 
and especially by those with which agrees the ko.66\ov 7rpwrov 
of Aristotle, 1 i.e. which are reciprocal, or approach thereto. - 
I think there is reason in advising this method, especially as 
regards the precepts wherein medicine is ratiocinative ; but in 
proportion as it is empirical, it is not so easy nor so certain 
to form universal propositions. Further, there are usually 
complications in particular diseases, which form, as it were, 
an imitation of substances, so that a disease is like a plant or 
an animal, which demands a history by itself, i.e. they are 
modes or forms of being with which agrees what we have said 
of bodies or substantial things, a quartan 2 fever being as diffi- 
cult to examine thoroughly as gold or quicksilver. Thus it is 
well, without detriment to the universal precepts, to seek in the 

tus Fabri, who accused him of blasphemy and impiety, because he had not 
seen the bearing of his reasonings. Sennert protested that he had never main- 
tained the immortality of the souls of animals, but it was a strict consequence 
of his principle. 

In his Institutiones medicse et de origine animarum in brutis, Wittemberg, 
1611, 4to, Sennert endeavored to unite for the first time the principles of Galen 
(c/. ante, p. 407, note 1) with those of Paracelsus, 1493-1541. His Opera omnia, 
eel. novissima, Lugduni, 1676, 6 vols., fol. Sprengel says he was "the most 
celebrated of all the conciliators of the seventeenth century," "a man who 
united to immense erudition and to a perfect knowledge of the ancients great 
credulity, a taste little refined, and a weak judgment." — Tr. 

1 Aristotle limited scientific consideration to that which is universally or 
for the most part valid. His K.a.66kov ttp&tov is the universal in its original and 
proper sense, as the essential attribute of individual things in which alone it 
has any realization, and whose essence consists in just this realization of the 
universal in them. Tbis universal is conceived of as the cause, and as such 
becomes the middle term in the syllogism, and constitutes the absolutely essen- 
tial element in logical demonstration, in the absence of which the reasoning 
has no validity. Cf. Wallace, Outlines of the Philos. of Aristotle, 3d ed., §§ 23, 
32-34, pp. 47, 64 ; Zeller, Philos. d. Griech. II. 2 [Vol. 4] , 304 sq., 3d ed. ; Prantl, 
Gesch. d. Loc/ik, 1, 104 sq., 119 sq. ; Windelband, A Hist, of Philos., trans, by 
J. H. Tufts, Ph.D., 133-143. New York: Macmillan & Co., 1893. — Tr. 

2 I.e. a fever running in periods of four days. — Tr. 



ch. vii] ON HUMAN UNDEKSTANDING 489 

different kinds of diseases methods of healing, and remedies 
which satisfy many symptoms and complications of causes, 
and especially to gather together those which experience has 
approved. This Sennertus has not sufficiently done, for com- 
petent judges have remarked that the compositions of the 
receipts he proposes are often made more ex ingenio by 
estimate than authorized by experience, as would be neces- 
sary if one would be more certain of his case. I think then 
that the better course would be to unite these two ways, and 
not to complain of repetitions in a matter so delicate and so 
important as is medicine, wherein I find that we lack what 
we have in too large measure in my view in jurisprudence, i.e. 
books of particular cases, and repertories of observations 
already made. For I think that a thousandth part of the 
books of the jurisconsults would suffice us, but that we would 
have none too many in the matter of medicine, if we had thou- 
sands more of well-detailed observations. The fact is, juris- 
prudence is wholly based upon reasons in regard to which 
nothing is expressly indicated by laws or by customs. For we 
can always derive it either from law or, in default of this, 
from natural right by means of the reason. The laws of 
each country are finished and determined, or may become so; 
while in medicine, the principles of experience, i.e. the ob- 
servations, cannot be too greatly multiplied in order to give 
more opportunity to the reason to decipher what nature only 
half allows us to know. For the rest, I do not know any one 
who employs the axioms in the way that the clever author of 
whom you speak does (§§ 16, 17), as if any one, in order to 
demonstrate to a child that a negro is a man, availed himself 
of the principle what is, is, by saying : a negro has a rational 
soul; now the rational soul and man is the same thing, and 
consequently if having a rational soul he were not a man, it 
would be false that what is, is, or rather one and the same 
thing would be or would not be at the same time. For with- 
out employing these maxims, which are not in season here, 
and do not enter directly into the reasoning, as they also do 
not advance it in any respect, everybody will be content to 
reason thus: a negro has a rational soul, whoever has a 
rational soul is a man, therefore the negro is a man. And- if 
any one assuming that there is no rational soul if it does not 



490 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

appear to us, concluded that infants just born and imbeciles 
do not belong to the human species (as, in fact, the author 
states that he has conversed with very reasonable persons .who 
made this denial), I do not think that the bad use of the 
maxim, that it is impossible for a thing to be and not to be, 
would delude them, nor that they think of it even in drawing 
this conclusion. The source of their error would be an exten- 
sion of the principle of our author, which denies that there is 
anything in the soul of which it is not conscious, while these 
gentlemen would proceed as far as to deny the soul itself, 
when others did not perceive it. 



CHAPTER VIII 

OF TRIFLING PROPOSITIONS 

Ph. I believe, indeed, that reasonable persons have not 
been disinclined to employ identical axioms in the way of 
which we have just spoken. § 2. It also seems that these 
purely identical maxims are only trifling propositions or nugato- 
rice, as the schools indeed call them. I should not be content 
to say that they seem thus, did not your surprising example 
of the demonstration of conversion by the agency of the identi- 
cals 1 make me proceed, bridle in hand, thenceforth, when 
contempt for anything is the question. But I shall tell you 
that what you allege in their favor proclaims them wholly 
trifling; viz. : (§ 3) you recognize at first sight that they con- 
tain no instruction unless to show a man sometimes the ab- 
surdity in which he is involved. 

Th. Do you count that as nothing, sir, and do you not recog- 
nize that to reduce a proposition to absurdity is to demonstrate 
its contradictory? I indeed believe that you will instruct no 
man by telling him that he must not deny and affirm the same 
thing at the same time, but you instruct him by showing him 
by the force of the consequence, that he does this without 
thinking of it. It is difficult, in my opinion, always to pass 

1 Cf. New Essays, Bk. IV., chap. 2, ante, p. 409. — Tr. 



ch. Tin] ON HUMAN UNDERSTANDING 491 

from these apagogical demonstrations, i.e. demonstrations which 
reduce to absurdity, and to prove everything by the ostensives, 1 
as they are called; and geometers, who are very curious on 
this point, have tried it sufficiently. Proclus speaks of it 
from time to time, when he sees that certain ancient geome- 
ters, coining after Euclid, have found a demonstration more 
direct (as they think) than his. But the silence of this an- 
cient commentator sufficiently shows that they did not always 
accomplish it. 

§ 3. Ph. You will at least admit, sir, that a million proposi- 
tions may be formed at little expense, but also of very little 
use; for is it not trifling to remark, for example, that the 
oyster is the oyster, and that it is false to deny it, or to say 
that the oyster is not the oyster? As to which our author 
agreeably says that a man who would make this oyster some- 
times the subject, sometimes the attribute, or the predicatum, 
would justly be like a monkey who should amuse himself by 
throwing one oyster from one hand to the other, which pro- 
ceeding could altogether as well satisfy the hunger of the 
monkey as these propositions are capable of satisfying the 
understanding of man. 

Th. I find that this author, as full of intelligence as gifted 
with judgment, has every reason in the world for speaking 
against those who would so use them. But you certainly see 
how the identicals must be employed to render them useful; 
viz. : by showing by force of consequences and definitions that 
other truths which you wish to establish reduce to them. 

§ 4. Ph. I know it and I see clearly that they may be 
applied with much stronger reason to propositions which 
appear trifling and on many occasions are so, wherein a part 
of the complex idea is affirmed of the object of this idea, as 
in the statement : lead is a metal In the mind of a man who 
is acquainted with the meaning of these terms and who knows 
that lead signifies a very heavy fusible and malleable body, 
there is this use alone, that in saying metal, you indicate to 
him at once many simple ideas instead of enumerating them 
one by one. § 5. The same is true when part of the defrni- 

1 I.e. direct demonstrations, a term used as the opposite of the indirect or 
apagogical demonstrations, which show the truth of a thing hy proving the 
absurdity of denying it. — Tk. 



492 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

tion is affirmed of the thing defined; as in the statement: 
all gold is fusible, supposing you have defined gold as a yellow, 
heavy, fusible, and malleable body. Again, to say that the 
triangle has three sides, that man is an animal, that a palfrey 
(palefroy, an old French word) is an animal which neighs, 
serves to define the words, but not to teach anything besides 
the definition. But we learn something from the statement 
that man has a notion of God and that opium plunges him 
into sleep. 

Th. Besides what I have said of the identicals which are 
wholly so, we shall find that these semi-identicals have also a 
particular use. For example, a wise man is always a man; 
that gives us the knowledge that he is not infallible, that he 
is mortal, etc. Some one in danger needs a pistol-ball, and 
lacks the lead to found it in the form he has ; a friend says 
to him : remember that the silver you have in your purse is 
fusible; this friend will not teach him a quality of the silver, 
but will make him think of a use he may make of it, in order 
to have pistol-balls in this pressing need. A large part of 
moral truths and of the most beautiful sentences of authors is 
of this nature: they very often teach us nothing, but they 
make us think at the right time of what we know. That 
iambic senarius of the Latin tragedy, — 

Cuivis potest accidere, quod cuiquam potest, 1 

which might be expressed thus, although less prettily: that 
which may happen to one, may happen to everybody, only 
makes us remember the human condition, quod nihil humani a 
nobis alienum putare debemus.' 2 This rule of the jurisconsults : 
qui jure suo utitur, nemini facit injuriam 3 (he who uses his 

1 Publilius Syrus, in Seneca, Be, Tranquillitate, chap. 11. — Tr. 

2 Of. Terence, Heauton. 1. 1. 23-25: " Homo sum; humani nihil a me alie- 
num puto." — Tr. 

3 Schaarschmidt states that this rule of the jurisconsults comes from the 
"Begulseet prsecepta juris," which were customarily appended to the older 
editions of the Institutiones. The exact phrase does not occur in the Corpus 
Juris Civilis; but cf. Digest, Lib. XXXIX., Tit. II., 24, ad Jin., where Trebatius 
says: " non teneri me damni infecti: neque enim existimari, operis mei vitio 
damnum tibi dari in ea re, in qua jure meo usus sum " ; ib. 26 : " Proculus ait, 
cum quis jure quid in suo faceret," etc.; Digest, Lib. L., Tit. XVII., 55, where 
Gaius says: " Nullus videtur dolo facere, qui suo jure utitur" ; ib. 129, where 
Paulus says : " Nihil dolo creditor facit, qui suum recipit." — Tr. 



ch. vm] ON HUMAN UNDEESTANDING 493 

own right, injures no one) appears trifling. But it is very 
useful on certain occasions and makes one justly think of 
what is necessary. If, for instance, any one raised his house 
as far as he is allowed by the statutes and usages, and by so 
doing deprived his neighbor of some view, he would pay this 
neighbor at once, according to this rule of law, if he ventured 
to complain. For the rest, propositions of fact, or experiences, 
like that which states that opium is a narcotic, carry us farther 
than the truths of pure reason, which can never make us go 
beyond that which is in our distinct ideas. 1 As for this propo- 
sition, that every man has a notion of God, it is from the 
reason, since notion signifies idea. For the idea of God, ac- 
cording to my view, is innate in all men : but if this notion 
signifies an idea in which you actually think it, it is a propo- 
sition of fact which depends on the history of the human race. 
§ 7. Finally, to say that a triangle has three sides is not so 
identical as it seems, for a little attention is required to see 
that a polygon must have as many angles as sides; it would 
also have an additional side, if the polygon were not supposed 
to be closed. 

§ 9. Ph. It seems that the general propositions concerning 
substances are for the most part trifling, if they are certain. 
He who knows the meanings of the words : substance, man, 
animal, form, soul, vegetative, sensitive, rational, will form 
from them many indubitable but useless propositions, partic- 
ularly about the soul, of which we often speak without know- 
ing what it really is. Every one may see an infinite number 
of propositions, reasonings, and conclusions of this nature in 
the books of metaphysics, scholastic theology, and a certain 
kind of physics, the reading of which will teach him nothing 
more of God, spirits, and bodies than he knew before having 
run through these books. 

Th. It is true, that abstracts of metaphysics and such other 
books of this character as are commonly seen, teach only 
words. To say, for example, that metaphysics is the science 
of being in general, which explains the principles and affec- 
tions emanating from it; that the principles of being are 

1 Truths of fact furnish occasion for inductive conclusions which enlarge 
our knowledge ; while truths of reason can only be explicated, or made clearer 
as to their already existing content. — Tr, 



494 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

essence and existence; that the affections are either primi- 
tive, viz. : unity, truth, the good, or derivative, viz. : iden- 
tity, diversity, simplicity, complexity, etc., and, in speaking 
of each of these terms, to give only vague notions and verbal 
distinctions is indeed to abuse the name of science. \jBut we 
must render this justice to the more profound Scholastics, 
like Suarez 1 (whom Grotius valued so highly) and admit that 
there is sometimes in them discussions of value, as upon the 
continuum, the infinite, the contingent, the reality of abstracts, 
the principles of individuation, the origo et vacuum formarum, 
the soul and its faculties, the concurrence of God with his 
creatures, etc., and even in ethics, upon the nature of the 
will and the principles of justice ; in a word, we must admit 
that there is still some gold in these scoriae, but it is only 
enlightened persons who can profit from it; and to load the 
youth with the rubbish of inutilities, because there is some- 
thing of value here and there, would be badly to dispose of 
the most precious of all things, time. For the rest, we are 
not wholly destitute of general propositions regarding sub- 
stances which are certain, and deserve to be known; there are 
grand and beautiful truths concerning God and the soul which 

1 Francisco Suarez, 1548-1617, a famous Jesuit and a distinguished philoso- 
pher, theologian, and philosophical jurist, was "the last great Scholastic." 
In philosophy he was a moderate Thomist. As a theologian, he advocated the 
system known as " congruism." In his Tractatus de legibus ac Deo legislator e, 
reprinted, London, 1679, wherein he was to a certain extent the forerunner of 
Grotius and Pufendorf , he maintained the theory of conditional obedience to 
authority. For an account of his views on natural law and sovereignty, cf. 
Larousse, Grande Diet. Univ. de XIX e Siecle, Vol. 14, pp. 1164c-1165a; for 
his "congruism," ibid., Vol. 4, p. 934 a. His Opera omnia, 23 vols., fol., ap- 
peared at Mainz and Lyons, 1630 sq., Venice, 1640, new revised ed., 26 vols., 
8vo, Besancon and Paris, 1856-62. The most important of his works are, per- 
haps, the Disputationes metaphysicss, 1605, and the Tract, de leg., cited above. 
For an account of his philosophy, cf. Stockl, Gesch. de Philos. d. Mittelalters, 
III. [Vol. 4], 634 sq., and K. Werner, Suarez u. d. Scholastik d. letzten Jahr- 
hunderte, Regensburg, 1861. 

Huig van Groot — Latin, Hugo Grotius — cf. ante, p. 285, note 1, one of the 
founders of the philosophy of law, in his theological writings occasionally cites 
Suarez as an authority ; cf., for example, Opera omnia theologica, Amsterdam, 
1679, Vol. 4, pp. 206, a, 50, 621, a, 54 ; and in his Epistolse ad Gallos, epist. 154 
ad Joa. Cordesium, p. 335, ed. Leipzig, 1674, and new ed. 1684, also Epistolse 
quotquot reperiri potuerunt, epist. 329, p. 118, Amsterdam, 1687, praises him 
thus: " Quorsum tantus Suarezii contemtus? hominis, si quid recte judico, 
in philosophia cui hoc tempore conuexa est scholastica, tantse subtilitatis, ut 
vix quemquam habeat parem? " — Tr. 



ch. vin] ON HUMAN UNDERSTANDING 495 

our clever author has taught either in his own right or in 
part after others. ■ We have perhaps added something also 
thereto. And as for general knowledge concerning bodies, 
considerable additions are being made to what Aristotle left, 
and it should be said that physics, even general physics, has 
become much more real than it was heretofore. As for real 
metaphysics, we are beginning, as it were, to establish it, and 
we find important truths grounded in reason and confirmed by 
experience, which belong to substances in general. I hope, 
also, that I have advanced a little the general knowledge of 
the soul and of spirits. Such a metaphysic was the demand 
of Aristotle, it is the science which he called ZrjTovfxevr), the 
desired (la desiree) or that which he sought, which must be as 
regards the other theoretic sciences what the science of happi- 
ness is to the arts which it needs, and what the architect is to 
the workmen. This is why Aristotle said that the other 
sciences depend upon metaphysics as the most general science 
and must derive from it their principles, demonstrated by it. 1 
You must know also that true ethics is to metaphysics what 
practice is to theory, because upon the doctrine of substances 
in common depends the knowledge of spirits and particularly 
of God and the soul which gives a proper meaning to justice 
and virtue. For as I have elsewhere 2 remarked, if there were 
neither providence nor a future life, the wise man would be 
more limited in the practice of virtue, for he would refer 
everything merely to his present satisfaction, and even this 
satisfaction, which appears already in Socrates, in the em- 
peror Marcus Aurelius, in Epictetus and other ancients, 3 

1 Cf. Aristotle, Metaphys., A, 2, 982*-983 », the object of which is to prove 
the dependence of the other sciences upon metaphysics, and in which the term 
^Tetf frequently occurs in this specific sense; cf. especially 982 b , 7, 8: i£ a-nav- 

Tiav ovv twv eipr)|U.evu)i> eVi ttj>> o.uttji' <E7rio-Tr; l u.-»)i' niirrei to ^f)TOVji.evov ovofxa. For the 

comparison to the architect, cf. 1, 981 a , 30. — Tr. 

2 Leibnitz refers perhaps to what he said in New Essays, Bk. I., chap. 2, 
§ 2, Th. (2), ante, pp. 86-87; or in the Preface to his Codex juris gentium. 
diplomatiwis, § 13 (Dutens, 4, Pt. III., 296) : " Ut vero universali demonstra- 
tione conficiatur, omne honestum esse utile, et omne turpe damnosum, assu- 
menda est immortalitas animfe, et rector universi Deus," etc. — Tr. 

3 Marcus Aurelius Antoninus, 121-180, the noblest of the Roman Emperors, 
whose Meditations or Thoughts exhibit the Stoic philosophy at its best on the 
moral and religious side, and present a morality nearer to that of the New 
Testament than that of any other pagan writer. Eds. of the Greek Text 
to. eis aiirov by J. M. Schultz, Leipzig, 1802, reprinted by Tauchnitz, 1821, and 



496 * LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

would not be so well grounded always without these beautiful 
and grand views which the order and harmony of the universe 
open for us even in a future without limits; otherwise the 
tranquillity of the soul would be only what is called' a forced 
patience, so that we may say that natural theology, comprising 
two parts, theoretical and practical, contains altogether real 
metaphysics and the most perfect ethics. 1 
y% 12. Ph. There is doubtless knowledge which is far re- 

by J. Stick, Leipzig, 1882. Eng. trans., The Thoughts of the Emperor M. 
Aurelius Antoninus, by Geo. Long, revised ed. in Bohn's Class. Library ; also 
Boston: Ticknor and Fields, 1864. On his life and philosophy, cf. Zeller, 
Philos. d. Griech., III., 1 [Vol. 5], 754-763, 3d ed., 1880; Capes, Stoicism (in 
series of " Chief Anct. Philosophies," pub. by the Soc. for promoting Chris- 
tian Knowledge), chap. 13, pp. 200-239, London, 1880; F. W. Farrar, Seekers 
after God, pp. 257-317, London, Macmillan & Co., 1877. 

Epictetus, the date of whose birth and death is unknown, lived in Rome 
under Nero, 54-68, and his successors, and, when Domitian in 94 banished all 
philosophers from the Imperial City, went to Nicopolis in Epirus, and there 
taught till his death, which appears to have occurred in the reign of Trajan, 
98-117, or shortly after. At first a slave, but afterwards a freedman, he repre- 
sented Stoicism in the cottage, while in Aurelius we see it on the throne. He 
left no writings, but his discourses, Aiarp^aC, were carefully taken down as 
far as possible in his own words as he uttered them, by his pupil and admirer 
Arrian. The best ed. is that by Schweighauser, 6 vols., 8vo, Leipzig, 1799- 
1800. Eng. trans., The Discourses of Epictetus, with the Encheiridion and 
Fragments, by Geo. Long, in Bohn's Class. Library ; also by T. W. Higgiuson, 
Boston: Little, Brown & Co., 1865. On his life and philosophy, cf. Zeller, 
Philos. d. Griech., III., 1 [Vol. 5], 738-754, 3ded., 1880; Capes, Stoicism, chap. 
12, pp. 180-199; Farrar, Seekers after God, pp. 186-256, London, 1877. — Tr. 

1 The old scholasticism made natural theology a part of metaphysics, which 
included besides natural theology, ontology, cosmology, and psychology. Cf. 
Thos. Aquinas, Summa Theol., Pt. I., Quest. 1, Art. 1, ad fin. : " Unde theo- 
logia, quae acl sacram doctrinam pertinet, differt secundum genus ab ilia theo- 
logia quae pars philosophise ponitur." Leibnitz, in a writing without place or 
date, which Gerhardt (Leibniz, philos. Schrift., 4, 268, note **) thinks was 
undoubtedly addressed to the Duchess Sophie, says (G. op. cit., 4, 292, and 
Foucher de Careil, Nouvelles lettres et opuscules de Leibniz inedits, Paris, 
1857, p. 25) : " En effect la metaphysique est la theologie naturelle, et le meme 
Dieu qui est la source de tous les biens, est aussi le principe de toutes les con- 
noissances." Of. also Discours de metaphys., § 28, G. 4, 453. 

Leibnitz finds the source of ethical truths in natural theology, because God, 
the idea of whom is the subject of natural theology, is also the object of man's 
highest moral aspiration and effort, so far as he seeks lovingly to comprehend 
him, a point of view from which Leibnitz sought to develop the ethical con- 
ceptions published under the title of Deflnitiones ethicse, G. 7, 73 sq., Erdmann, 
670, trans. Duncan, Philos. Wks. of Leibnitz, 130, and which controls the 
thought-development in the Preface to the Codex juris gentium diplomaticus, 
cf. § 13, Dutens, 4, Pt. III., 296, in the The'odicee, Preface, G. 6, 26-28, E.469, 
Jacques, 2, 3-4, Janet, 2, 3-4, and in the Discours de metaphys., §§ 2-4, 35-37, 
G. 4, 427-430, 460-463. — Tr. 



en. ix] ON HUMAN UNDERSTANDING 497 

moved from being trifling or purely verbal. But this last 
seems to be that in which two abstracts are affirmed, the one 
of the other; for example, that parsimony is frugality, that 
gratitude is justice; and however specious these and other 
propositions sometimes appear at first sight, yet when we 
press their force, we find that it all amounts to nothing else 
than the signification of the terms. 

s Tli. But the significations of terms, i.e. definitions united 
with identical axioms, express the principles of all demonstra- 
tions : and as these definitions can make known at the same 
time the ideas and their possibility, it is plain that what 
depends on them is not always purely verbal. As for the 
example that gratitude is justice, or rather a part of justice, it 
is not to be despised, for it shows that what is called actio 
ingrati, 1 or the complaint which can be made against the 
ungrateful, should be less neglected in the tribunals. The 
Romans received this action against the Liberti, 2 or freedmen, 
and still to-day it should have place as regards the revocation 
of gifts. For the rest, I have already said/ elsewhere 3 that 
abstract ideas also may be attributed to one another, the genus 
to the species, as in the statements : duration is ■ a continuity, 
virtue is a habit; but universal justice is not only a virtue, 
but it is indeed the complete ethical virtue. 



CHAPTER IX 

OE OUR KNOWLEDGE OF OUR EXISTENCE 4 

§ 1. Ph. We have hitherto considered only the essences of 
things, and as our mind knows them only by abstraction, by 
detaching them from every particular existence, other than 
that which is in our understanding, they give us absolutely 
no knowledge of any real existence. And the universal prop- 

1 Of. Cod. Justin., 8, 56, 1, 8, and 10. — Tr. 

2 Gerhardt, Erdmann, and Janet read "les libertes " ; Jacques reads "les 
liberes." — Tr. 

3 Of. Bk. III., chap. 3, § 10, Th., ante, p. 313. — Tr. 

4 Locke's title is, " Of our knowledge of existence," Philos. Works, Vol. 2, 
p. 228, Bonn's ed. — Tr. 

2 K 



498 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

ositions of which we may have a certain knowledge, do not 
relate to existence. Further, every time we attribute anything 
to an individual of a genus or a species by a proposition, which 
would not be certain if the same were attributed to the genus 
or species in general, the proposition belongs only to the exist- 
ence and makes known only an accidental union in the things 
existing in particular, as when we say, such a man is learned. 

Th. Very well, and it is in this sense that the philosophers 
also, distinguishing so often between, what is essence and what 
existence, refer to existence everything which is accidental or 
contingent. Very often we do not even know whether the uni- 
versal propositions, which we know only by experience, are 
not perhaps accidental also, because our experience is limited ; 
as in the countries where water is not frozen, this proposition 
which will be formed about it, that water is always in a fluid 
state, is not essential, and we know it by coming into colder 
countries. But we may take the accidental in a more limited 
sense, so that there will be, as it were, a mean between it and 
the essential; and this mean is the natural (le naturel), i.e. that 
which does not belong to the thing necessarily, but which, 
nevertheless, agrees with it of itself if nothing prevents. 
Thus, some one might maintain that it is not indeed essen- 
tial, but that it is at least natural, for water to remain fluid. 
We might maintain this, I say, but it is not, however, a 
demonstrated fact, and perhaps the inhabitants of the moon, 
if there are any, would have reason to believe the statement 
no less grounded that it is natural for water to be frozen. 
There are other cases, however, where the natural is less 
doubtful; for example, a ray of light always continues straight 
in the same medium unless it accidentally meets some surface 
which reflects it. For the rest, Aristotle was accustomed to 
refer to matter the source of accidental things ; * but then we 
must understand thereby secondary matter, i.e. the heap or 
mass of bodies. 

§ 2. Ph. I have already 2 remarked, following the excellent 
English author who wrote the Essay concerning Understand- 
ing, that we know our existence by intuition, that of God by 

1 Cf. MetaphyS., E, 2, 1027 a , 14: wore r) vKi) eo-T<xi aiTta. i) ivSexofi-ivr} Trapa to ios 
inl to iroAv aAAcos toO o-v/j./3e/37jK6Yos. — Tk. 

2 Cf. Bk. IV., chap. 3, § 21, ante, p. 439.— Tr. 



ch. x] ON HUMAN UNDERSTANDING 499 

demonstration, and that of other things by sensation. § 3. 
Now this intuition which makes known our existence to our- 
selves, makes it known to us with an evidence complete, 
incapable of being proved and having no need of proof; so 
that even when I attempt to doubt all things, this doubt itself 
does not allow me to doubt my own existence. In fine, we 
have on this point the highest degree of certainty that can be 
imagined. 

Th. I am entirely agreed as to all this. And I add that 
the immediate apperception of our existence and of our 
thoughts furnishes us the first truths a posteriori, or of fact, 
i.e. the first experiences, as the identical propositions contain 
the first truths a priori, or of reason, i.e. the first lights (les 
premieres lumieres). 1 Both are incapable of proof, and may be 
called immediate; the former, because they are immediate 
between the understanding and its object; the latter, because 
they are intermediate between the subject and the predicate. 



CHAPTEE X 

OF OUR KNOWLEDGE OF THE EXISTENCE OF GOD 

§ 1. Ph. God having given to our soul the faculties with 
which it is adorned, has not left himself without a witness ; 
for the senses, perception, and the reason furnish us manifest 
proofs of his existence. 

Th. God has not only given the soul faculties suitable for 
knowing him, but he has also impressed upon it characters 
which indicate him, although the soul needs faculties to per- 
ceive these characters. But I do not wish to repeat the discus- 
sions we have already had upon ideas and innate truths, 
among which I reckon the idea of God and the truth of his 
existence. Let us come rather to the fact. 

Ph. Now, although the existence of God is the truth most 
easily proved by the reason, and its evidence equals, if I am 
not mistaken, that of mathematical demonstrations, it yet 
demands attention. It needs at once only reflection upon 

1 Schaarschmidt translates : "die ersten Erleuchtungen aus dem Innern," 
i.e. the first illuminations from within. — Tk. 



500 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

ourselves and our own indubitable existence. § 2. Thus I sup- 
pose that every one knotvs that something actually exists, and that 
thus there is a real being. If there is any one who can doubt 
his own existence, I declare that I do not speak to him. § 3. 
We know also by an intuitive knowledge that bare nothing can- 
not produce a real being. Whence it follows, with mathemat- 
ical evidence, that something has existed from all eternity, since 
everything which has a beginning must have been produced 
by something else. § 4. Now every being which draws its 
existence from another, draws also from it all it has, and 
all its faculties. The eternal source of all beings is then 
also the principle of all their powers, so that this eternal being 
must be also all-powerful. § 5. Further, man finds in himself 
knowledge. There is, then, an intelligent being. ISTow it is im- 
possible for a thing absolutely destitute of knowledge and per- 
ception to produce an intelligent being, and it is contrary to 
the idea of matter, deprived of thought, to produce it of itself. 
The source of things is then intelligent, and there has been an 
intelligent being from all eternity. § 6. An eternal, very power- 
ful, and very intelligent being is what we call God. If, how- 
ever, any one were found so unreasonable as to suppose that 
man is the only being having knowledge and wisdom, but that, 
nevertheless, he has been formed by pure chance, and that it 
is this same principle, blind and without knowledge, which 
carries on all the rest of the universe, I shall advise him to 
examine at his leisure the wholly solid and emphatic censure 
of Cicero ("De Legibus," lib. 2). Certainly, he says, no one 
could be so foolishly arrogant as to think that he has within 
himself an understanding and reason, and yet that there is no 
intelligence governing the heavens and all this vast universe. 1 
From what I have just said it clearly follows that we have a 
more certain knowledge of God than of anything else outside us. 
Th. I assure you, sir, with perfect sincerity, that I am ex- 
tremely sorry to be obliged to say something against this 
demonstration ; but I do it solely in order to give you an op- 
portunity to fill up the void. It is principally in the part 

1 Cicero, Be Leg., Bk. II., chap. 7: " Quid est enim verius, quam neminem 
esse oportere tarn stulte arrogantem, ut in se rationem et menteni putet iuesse, 
in ccelo mundoque non putet? Ant ut ea quae vix summa ingenii ratione com- 
prekendat, nulla ratione moveri putet ? " — Tr. 



OH. x] ON HUMAN UNDERSTANDING 501 

where you conclude (§ 3) that something has existed from all 
eternity. I find therein some ambiguity, if that means that 
there never has been any time in which nothing existed. I admit 
it, and it follows truly from the preceding propositions by 
an inference wholly mathematical. For if there had always 
been nothing, there would always have been nothing, nothing 
being unable to produce a being; then we ourselves should not 
be, which is contrary to the first truth of experience. But the 
consequence appears at once, that by the statement that some- 
thing has existed from all eternity, you mean an eternal 
thing. But it does not at all follow in virtue of what you 
have hitherto advanced, that if there has always been some- 
thing, there has always been a certain thing, i.e. an eternal 
being. For certain opponents will say that I have been pro- 
duced by other things, and these things by others. Further, 
if some admit eternal beings (as the Epicureans their atoms) 
they will not think themselves compelled for that reason to 
admit an eternal being who is the only source of all the 
others. For if they should admit that this which gives exist- 
ence, gives also the other qualities and powers of the thing, 
they will deny that a single thing gives existence to the 
others, and they will say also that in each thing many others 
must concur. Thus we shall not reach by this alone a source 
of all the powers. Yet it is very reasonable to judge that 
there is one, and also that the universe is governed with wis- 
dom. But when we believe matter susceptible of thought, we 
may be disposed to believe that it is not impossible that it 
may produce something. At least it will be difficult to bring 
forward a proof which does not show at the same time that it 
is wholly incapable of it; and, assuming that our thought 
comes from a thinking being, may we take it as admitted, 
without prejudice to the demonstration, that this must be 
God? 

§ 7. Ph. I do not doubt that the excellent man from whom 
I have borrowed this demonstration is capable of perfecting 
it; and I shall try to influence him to do so, since he could 
scarcely render a greater service to the public. You also de- 
sire it. This makes me think that you do not consider it 
necessary, in order to shut the mouths of atheists, to make 
everything revolve upon the existence of the idea of God in 



502 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

us, as some do, who attach themselves too strongly to this 
favorite discovery even to rejecting all other demonstrations 
of the existence of God, 1 or at least attempting to weaken 
them and forbidding to employ them as if they were weak or 
false; although at bottom they are proofs which show us so 
clearly and in a manner so convincing the existence of this 
sovereign being by the consideration of our own existence, 
and of the sensible parts of the universe, that I think no wise 
man ought to resist them. 

\J Tli. Although I am for innate ideas, and in particular for 
that of God, I do not think that the demonstrations of the 
Cartesians drawn from the idea of God are perfect. I have 
shown fully elsewhere 2 (in the "Actes de Leipsic," and in 
the "Memoires de Trevoux") that what Descartes has bor- 
rowed from Anselm, 3 Archbishop of Canterbury, is very beau- 

1 Descartes relied mainly, and Spinoza exclusively, on the ontological or a 
priori argument for the proof of God's existence. Spinoza's system, in fact, 
did not admit the possibility of any other argument, since God is the only sub- 
stance and all other things are merely modes, accidents, or expressions of that 
substance. Cf. Descartes, Meditations, III. and V., Veitch's trans., pp. 115 sq., 
143 sq., Princip. Philos., Pt. I., §§ 13 sq., Veitch, pp. 198 sq., Discours de la 
Methode, Pt. IV., Veitch, pp. 34 sq.; Spinoza, Ethica, Pt. I., ed. Van Vloten and 
Land, Vol. 1, pp. 39 sq., trans. Elwes, Vol. 2, pp. 45 sq.; letter to De Vries, 
V. V. & L., 2, 34, trans. E. 2, 315. Also on Descartes, Windelband, Hist, of Philos., 
trans, by Tufts, 392-3, 405 ; on Spinoza, ibid., 401, 407-10. Leibnitz, while seek- 
ing to correct and complete the ontological argument, makes the teleological 
form of the a posteriori argument, in his doctrine of monads and their pre- 
established harmony, one of the constituent principles of his system. Cf. Coi\- 
fessio natitrse contra atheistas, 1668, Gerhardt, 4, 105-109, Erdmann, 45-47, 
Dutens, 1, 5-8; Principes de la nature et de la grace, §§ 11 sq., G. 6, 603, E. 
716, trans. Duncan, 214, Monadologie, §§ 38 sq., G. 6, 613, E. 708, trans. D., 223. 
Leibnitz's doctrine of monads demands the existence of God as its necessary 
ground and complement. Cf. ante, p. 363, note 1. He regarded all the argu- 
ments for God's existence as valuable and urged men to perfect them. Cf. 
infra, p. 505, note 2. On his doctrine, cf. Windelband, op. cit., 420-425. — Tr. 

2 Leibnitz means the Med. de Cog., Ver. et Id., published in the "Acta 
Erud. Lips.," Nov., 1684, and found in Gerhardt, 4, 422, Erdmann, 79, Dutens, 
2, Pt. I., 14, Janet, 2, 514 (in French) , trans. Duncan, 27 ; and the De la demon- 
stration Cartesienne, etc., published in the " Memoires de Trevoux," 1701, G. 
4, 405, E. 177, Dutens, 2, Pt. I., 254, Janet, 2, 568, trans. Duncan, 136.— Tr. 

3 Anselm, 1033-1109, archbishop of Canterbury from 1093 till his death, and 
the real founder of the Christian Scholasticism of the Middle Age, was a dis- 
tinguished philosopher and theologian, whose fame rests chiefly upon his onto- 
logical or a priori argument for the existence of God, and his theory of the 
incarnation and atonement. His Opera are found in Migne, Patrol. Cur. 
Compl., Vol. 155. The most important for philosophy are the Cur Deus 
Homo ?, the Monologium, and the Proslogium. The two latter, with Gaunilo's 



ch. x] ON HUMAN UNDERSTANDING 503 

tiful and really very ingenious, but that there is still a gap 
therein to be filled. This celebrated archbishop, who was 
without doubt one of the most able men of his time, congratu- 
lates himself, not without reason, for having discovered a 
means of proving the existence of God a priori, by means of 
its own notion, without recurring to its effects. And this is 
very nearly the force of his argument : God is the greatest, 
or (as Descartes says) the most perfect of beings, or rather a 
being of supreme grandeur and perfection, including all de- 
grees thereof. That is the notion of God. See now how 
existence follows from this notion. To exist is something 
more than not to exist, or rather, existence adds a degree to 
grandeur and perfection, and as Descartes states it, existence 
is itself a perfection. Therefore this degree of grandeur and 
perfection, or rather this perfection which consists in exist- 
ence, is in this supreme all-great, all-perfect being : for otherwise 
some degree would be wanting to it, contrary to its definition. 
Consequently this supreme being exists. The Scholastics, 
not excepting even their Doctor Angelicus, 1 have misunder- 

refutation of the Proslogium, entitled Liber pro insipiente, and Anselm's 
reply, Liber apologeticus, were edited by C. Haas, Tubingen, 1863. There is 
a French trans., with notes, of the Monologium and Proslogium by Bouchitte, 
Le Rationalisme Chretien, Paris, 1842; and an English trans, of the Pros- 
logium and Lib. apologet. in the "Bibliotheca Sacra," Vol. 8 [1851], pp. 529 
sq., 704 sq., and of the Cur Deus Homo?, ibid., Vol.11 [1854], pp. 729 sq., 12 
[1855], 52 sq. His ontological argument is found in the Proslogiu?n and the 
Liber apologeticus. An excellent account of it is given in Ueberweg-Heinze, 
Gesch. d. Philos., 7th ed., Berlin, 1888, Vol. 2, p. 152 sq., Eng. trans, from 4th 
German ed., New York, 1871, Vol. 1, pp. 383-86. Cf. also Windelband, Hist, 
of Philos., trans, by Tufts, pp. 291-294; Mulford, The Republic of God, pp. 4, 
5, 4th ed., Boston, 1882. For further account of Anselm's life and philosophy, 
cf. Hasse, Anselm von Canterbury, 2 vols., Leipzig, 1843, 1852 (ontolog. argt. 
in Vol. 2, pp. 233-286) ; Stockl, Gesch. d. Philos. d. Mittelalters, 1, 151-208 ; 
Haureau, Histoire de la Philos. Scholastique, Paris, 1872-80, 1, 265-87. 

For expositions and criticisms of the ontological argument, cf. Kant, Krit. 
d. r. Vernunft., ed. Rosenkranz and Schubert, 2, 462-470, ed. Hartenstein, 
1838, 2, 456-464, 1867, 3, 405-411, ed. Kirchman, Leipzig, 1877, 1, 476-483, trans. 
Miiller, 1 vol. ed., 509-518; E. Caird, The Philos. of Kant, Glasgow, 1877, 
630, 642, The Grit. Philos. of Kant, New York, 1889, 2, 110, 120 ; Hegel, 
Vorlestmgen u. d. Beiveise vom Dasein Gottes, in his Philos. d. Relig., 
Anhang, 2, 357 sq., 2d ed., Berlin, 1840; Dorner, Christ. Glaubenslehre, 1, 201 
sq., Eng. trans., 1, 214 sq. ; Pfleiderer, Philos. d. Relig., 2, 271 sq., 2d ed., 
Berlin, 1884, Eng. trans., 3, 271 sq. — Tr. 

1 I.e. Thomas Aquinas, 1225 or 1227-1274. For his critique of the ontologi- 
cal argument, cf. Summa theologise, Pt. I., Quest. 2, Article 1; Contra gen- 
tiles, Bk. I., chap. 11; and Stockl, Gesch. d. Philos. d. Mittelalters, II., 1 [Vol. 



504 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

stood this argument, and have taken it as a paralogism; in 
which respect they were altogether wrong, and Descartes, 
who studied quite a long time the scholastic philosophy at the 
Jesuit College of La Fleche, had great reason for re-establish- 
ing it. It is not a paralogism, but it is an imperfect l demon- 
stration, which assumes something that must still be proved 
in order to render it mathematically evident; that is, it is 
tacitly assumed that this idea of the all-great or all-perfect 
being is possible, and implies no contradiction. And it is 
already something that by this remark it is proved that, 
assuming that God is %>ossible, he exists, which is the privilege 
of divinity alone. We have the right to presume the possi- 
bility of every being, and especially that of God, until some one 
proves the contrary. So that this metaphysical argument 
already gives a morally demonstrative conclusion, which de- 
clares that according to the present state of our knowledge we 
must judge that God exists, and act in conformity thereto. 
But it is to be desired, nevertheless, that clever men achieve 
the demonstration with the strictness of a mathematical proof, 
and I think I have elsewhere 2 said something that may serve 
this end. The other argument of Descartes, which under- 
takes to prove the existence of God because the idea of him is 
in our soul, and must have come from the original, is still less 
conclusive. For in the first place this argument has this de- 
fect, in common with the preceding, that it assumes that there 
is in vis such an idea, i.e. that God is possible. For what 
Descartes alleges, that in speaking of God we know what we 

2], 498. Spinoza also censures Aquinas for his rejection of the ontological 
argument ; cf. Korte Verhandeling van God, in Spinoza, Opera, ed. Van Vlo- 
ten and Land, Vol. 2, p. 265, and Schaarschmidt's German trans, of the same 
(Vol. 18 of J. H. v. Kirchmann's Philos. Bibliothek), p. 6, 2d ed., Berlin, 
1874. — Tb. 

1 Gerhardt reads " parfaite " ; Erdmann, Jacques, and Janet " imparfaite." 
The reading of G. is evidently a Ms. or typographical error, as the sense 
requires that of E., J., and J. — Tb. 

2 Leibnitz here probably refers to the De la demonstration Cartesienne, 
etc., 1701, Gerhardt, 4, 405, Erdmann, 177, Dutens, 2, Pt. I., 254, trans. Dun- 
can, 136. But cf. also G. 4, 292-294, 401-403, trans. Duncan, 132-136 ; Animad- 
versiones in partem, generalem Principiorum Cartesianorum, 1692, Pt. I., ad 
art. 14, 18, 20, G. 4, 358-60, trans. Duncan, 50-51, and Letters to Jacquelot, 
Nov., 1702, G. 3, 442 sq., Letter to Conring, Jan. 3, 1678, G. 1, 188, E. 78; cor- 
respondence with Eckhard, G. 1, 212 sq. ; and Stein, Leibniz it. Spinoza, Bei- 
lage VII., p. 306: Probatio existentise Dei ex ejus essentia. — Tb.. 



ch. x] ON HUMAN UNDERSTANDING 505 

are saying, and that consequently we have an idea, is a decep- 
tive indication, since in speaking of perpetual mechanical 
movement, for example, we know what we are saying, and 
yet this movement is an impossible thing, of which, conse- 
quently, we can have only an apparent idea. Secondly, this 
same argument does not sufficiently prove that the idea of 
God, if we have it, must come from the original. Bat I do 
not wish to delay here at present. You will say, sir, to me, 
that recognizing in us the innate idea of God, I ought not to 
say that we may question whether there is one. But I per- 
mit this doubt only in relation to a strict demonstration based 
upon the idea alone. For we are otherwise sufficiently assured 
of the idea and of the existence of God. And you will re- 
member that I have shown how ideas are in us, not always in 
such wise that we are conscious of them, but always in such 
wise that we may draw them from our own depths and make 
them perceivable. And this is also my belief concerning the 
idea of God, the possibility and existence of which I hold to 
be demonstrated in more than one way. And the pre-estab- 
lished harmony itself furnishes a new and incontestable means 
of so doing. 1 I believe also that nearly all the means which 
have been employed to prove the existence of God are good 
and might be of service, if we would perfect them, and I am 
not at all of the opinion that we should neglect that drawn 
from the order of things. 2 

§ 9. Ph: It will perhaps be proper to insist a little upon this 
question, whether a thinking being can come from a non- 
thinking being deprived of all sensation and knowledge such 
as matter may be. § 10. It is indeed quite evident that a 
part of matter is incapable of producing anything of itself, 
and of giving itself motion; its motion must then either be 
eternal or be impressed upon it by a more powerful being. If 
this motion were eternal, it would always be incapable of pro- 
ducing knowledge. Divide matter into as many little parts as 
you please, in order, as it were, to spiritualize it, give it all 

1 Of. ante, p. 363, note 1.— Tr. 

2 Leibnitz's idea is that all right thought, if thorough-going and deep enough, 
must at last lead back to God, its original source. None of the proofs of God's 
existence are therefore to be cast aside, but the essential significance of each 
is to be sought out and ascertained and its form perfected, and all are to be 
united into one organic whole. — Tr. 



506 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

figures and motions you wish, make it a globe, a cube, a prism, 
a cylinder, etc., whose diameters are only the one-millionth 
part of a gry, which is one-tenth of a line, which is one-tenth 
of an inch, which is one-tenth of a philosophical foot, which 
is one-third of a pendulum, each vibration of which in the 
latitude of forty-five degrees is equal to one second of time. 
This particle of matter, small as it is, will act upon other 
bodies of a size proportional to itself no differently than 
bodies of an inch or a foot in diameter act among them- 
selves. And we may hope as rationally to produce feeling, 
thought, and knowledge, by putting together gross parts of 
matter in a certain figure and motion, as by means of the 
smallest parts of matter in the world. These last knock, 
push, and resist each other just as the great ones do, and this 
is all they can do. But if matter could draw from its bosom 
feeling, perception, and knowledge, immediately and with- 
out machinery, or without the aid of figures and motions, 
then their possession must be an inseparable property of 
matter and of all its parts. To which one could add that, 
though the general and specific idea we have of matter 
leads us to speak of it as if it were a thing single in num- 
ber, yet all matter is not properly one individual thing, which 
exists in a material being or a single body that we know or 
can conceive. So that if matter were the first eternal think- 
ing being, there would not be one eternal infinite and think- 
ing being, but an infinite number of eternal infinite a thinking 
beings, independent of one another, whose forces would be 
limited and thoughts distinct, and who consequently could 
never produce this order, harmony, and beauty which is seen 
in nature. Whence it necessarily follows that the eternal 
first being cannot be matter. I hope that you, sir, will be 
more content with this reasoning taken from the celebrated 
author of the preceding demonstration than you have appeared 
to be with his demonstration. 

Th. I find the present reasoning the most solid in the 
world, and not only exact, but further profound and worthy of 
its author. I am perfectly of his opinion that no combination 
and modification of the parts of matter, however small they 

1 Locke has "finite" here, Philos. Works, Vol. 2, p. 237, Bonn's ed. Ger- 
hardt, Erdmann, Jacques, and Janet all read " infinis." — Tb. 



ch. x] ON HUMAN UNDERSTANDING 507 

may be, can produce perception; forasmuch as the gross par- 
ticles could not give it (as is manifestly admitted) and as 
all is proportional in the small parts to what may take place 
in the great. It is furthermore an important remark regard- 
ing matter which the author makes here, that it must not be 
taken as a thing single in number, or (as I have been wont 
to state it) as a true and perfect monad or unity, since it is 
only a mass of an infinite number of beings. Here this excel- 
lent author needed but a step to arrive at my system. For in 
fact I give perception to all these infinite beings, each one of 
which is like an animal endowed with a soul (or some active 
analogous principle which makes its true unity), together 
with what is necessary to this being in order to be passive 
and endowed with an organic body. Now these beings have 
received their nature, active as well as passive (i.e. what they 
have of immaterial and material), from a general and supreme 
cause, because otherwise, as the author very well says, being 
independent of one another, they could never produce this 
order, harmony, and beauty which is seen in nature. But 
this argument, which appears to possess only a moral certainty, 
is pushed to a necessity wholly metaphysical by the new hind 
of harmony I have introduced, which is the pre-established har- 
mony. For each one of these souls expressing in its way what 
takes place outside it and being unable to have any influence 
on other particular beings, or rather, being obliged to draw 
this expression from the depths of its own nature, each one 
must necessarily have received this nature (or this internal 
reason of the expression of that which is outside) from a 
universal cause upon which all these beings depend and which 
makes one perfectly in accord and correspondent with another ; 
a thing impossible without an infinite knowledge and power 
and with an artifice great as regards especially the spontane- 
ous agreement of the mechanism with the acts of the rational 
soul. The illustrious author 1 who made objections against it 

1 Leibnitz here refers to Pierre Bayle, 1647-1706, a celebrated critic, philoso- 
pher, and controversialist, who published in his Dictionnaire historique et 
critique, Rotterdam, 1695-97, 2 vols., 2d ed., revised and enlarged, 1702, article 
"Rorarius," a criticism of Leibnitz's Systeme nouveau de la nature, etc., pub- 
lished in the " Jour, des Savants," June, 1695, pp. 449 sq. Leibnitz sought to 
repel his criticisms in a writing, July, 1698, addressed to Basnage de Beauval, 
editor of the "Histoire des ouvrages des Scavans," and published therein, 



508 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

in his wonderful Dictionary doubted, as it were, whether this 
condition of things did not surpass all possible wisdom, saying 
that the wisdom of God did not appear to him too great for 
such an effect, and recognized at least that never had the 
feeble conceptions we may have of the divine perfection been 
so set in relief. 

§ 12. Ph. How delighted I am at this agreement of your 
thoughts with those of my author ! I hope you will not be dis- 
pleased, sir, if I give you an account also of the rest of his 
reasoning upon this article. First he examines whether the 
thinking being, upon whom all the other intelligent beings 
depend (and with much stronger reason all other beings) is 
material or not. § 13. It is objected that a thinking being 
might be material. But he replies that if that were so, it is 
enough that this be an eternal being which has an infinite 
knowledge and power. Further, if thought and matter can be 
separated, the eternal existence of matter will not follow 
from the eternal existence of a thinking being. § 14. It will 
further be asked of those who make God material whether 
they imagine that every part of matter thinks. In that case 
it will follow that there would be as many Gods as particles 
of matter. But if each part of matter does not think, then 
there is a thinking being composed of non-thinking parts, 
which has already been disproved. § 15. To say that any 
single atom of matter thinks, and that the other parts, 

July, 1698, p. 329 sq., cf. Gerhardt, Leibniz, philos. Schrift., 4, 517-24, Erdmann, 
150-154, Jacques, 1, 481-87, Dutens, 2, Pt. I., 74-80. In the 2d ed. of his Diction- 
naire, p. 2599 sq., Eng. trans, from 2d ed., carefully collated with the several 
eds. of the original, 5 vols., London, 1738, 4, 900-916, Bayle again discussed 
Leibnitz's views, and to this discussion Leibnitz made a thorough and search- 
ing reply, first published by Gerhardt, 4, 524-54, with the title: Extract du 
Dictionnaire de M. Bayle, article Rorarius, p. 2599 sqq. de V Edition de Van 
1702 avec mes remarques. Leibnitz pub. a revision of this detailed refutation, 
in 1712, in the " Histoire critique de la Republique des Lettres," Vol. 2, p. 78 
sq. Gerhardt has published it, 4, 544-71, with many additions by Leibnitz. 
Cf. also Erdmann, 183-191, Dutens, 2, Pt. I., 80-93, Janet, 2, 579-94. Leibnitz 
elsewhere frequently refers to Bayle, especially in the Theodice'e, in the pre- 
liminary essay entitled, Discours preliminaire sur conformite de lafoi avec la 
raison, in which Bayle's objections are carefully examined, and in Pts. II. and 
III., where he is cited on nearly every page, and which presents a continuous 
polemic against him. The composition of the Theodicee was occasioned by the 
discussions held by Leibnitz with Queen Sophie Charlotte of Prussia on philo- 
sophical and theological topics suggested by the reading of Bayle's Dictionary. 
For the correspondence of Leibnitz and Bayle, cf. Gerhardt, 3, 21 sq. — Tn. 



ch. x] ON HUMAN UNDERSTANDING 509 

though equally eternal, do not think, is to make the gratuitous 
statement that one part of matter is infinitely above another 
and produces thinking beings not eternal. 1 §16. If we will 
have it that the thinking eternal and material being is a cer- 
tain particular mass of matter whose parts are non-thinking, 
we fall back upon the view which has been disproved ; for the 
parts of matter are united in vain, they can acquire only a 
new local relation, which cannot give them knowledge. § 17. 
It matters not whether this mass is at rest or in motion. If 
at rest, it is only an inactive mass which has no privilege 
above one atom ; if in motion, since this motion, which distin- 
guishes it from other parts, is destined to produce thought, 
all these thoughts will be accidental and limited, each part by 
itself being without thought, and having nothing which regu- 
lates its movements. Thus there will be neither freedom, nor 
choice, nor wisdom, any more than in simple brute matter. 
§ 18. Some believe that matter is at least coeternal with God. 
But they do not say why : the production of a thinking being, 
which they admit, is much more difficult than that of matter 
which is less perfect. And perhaps (says the author) if we 
would withdraw ourselves a little from common ideas, give 
wings to our mind, and engage in the profoundest examina- 
tion we could make of the nature of things, we might be able to 
attain a conception, though in an imperfect manner, how matter 
may at first have been made, and how it commenced to exist by 
the poiver of this eternal first being. But we should see at the 
same time that to give being to a spirit is an effect of this 
eternal and infinite power much more difficult to comprehend. 
But because this would perhaps lead me too far (he adds) 
from the notions upon which the philosophy now in the world is 
based, it would not be excusable in me to deviate so far from 
them or to inquire, so far as grammar would permit, whether 
at bottom the commonly established opinion is contrary to 
this particular view; it would be wrong, I say, for me to 
engage in this discussion, especially in this corner of the world, 
where the received doctrine is good enough for my purpose, 
since it posits as an indubitable thing that if the creation or 
beginning of any substance whatever from nothing be once 

1 LeibDitz anticipates this argument of Locke by his law of continuity. — 
Tit. 



510 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

admitted, the creation of every other substance, except the 
Creator himself, may with the same facility be assumed. 

Th. You have given me genuine pleasure, sir, by giving me 
some account of a profound thought of your clever author, 
which his too scrupulous prudence has prevented him from 
producing in its entirety. It would be a great wrong, if he 
should suppress it and leave us there, after having made our 
mouths water. I assure you, sir, that I believe there is some- 
thing beautiful and important concealed behind this enigmati- 
cal manner. 1 The substance in large letters might make one 
suspicious that he conceives the production of matter in the 
same way as that of the accidents, which we find no difficulty 
in drawing from nothing : and in distinguishing his particular 
thought from the philosophy now prevalent in the world or in that 
corner of the earth, I do not know but that he had in mind the 
Platonists, who take matter as something fleeting and transi- 
tory, after the manner of the accidents, and had an altogether 
different idea of spirits and souls. 

§ 19. Ph. Finally, if some deny creation, by which things 
are made from nothing, because they cannot conceive it, our 
author, writing before he knew your discovery on the reason 
of the union of the soul and the body, holds against them, 
that they do not understand how voluntary movements are j>ro- 
duced in bodies by the will of the soul, and they cease not to 
believe the fact, being convinced by experience ; and he re- 
plies with reason to those who answer that the soul being una- 
ble to produce a new motion, produces only a new determina- 
tion of the animal spirits, he replies to them, I say, that the 
one is as inconceivable as the other. And nothing can be 
better said than what he adds on this occasion, that to wish 
to limit what God can do to what we can comprehend, is to 
give an infinite extent to our comprehension, or to make God 
himself finite. 

Th. Although now the difficulty regarding the union of the 
soul and the body has in my view been removed, there remain 
difficulties elsewhere. I have shown a posteriori by the pre- 

1 With regard to this riddle or enigma, Professor Schaarschmidt informs me 
that Raspe, in his ed. of the Nouveaux Essais, 1765, says, p. 409: " Mr. Coste 
l'a explique d'apres le Chevalier Newton dans la remarque (2) an § 18, de ce 
chapitre. Edition de Locke d'Amsterdam, de 1755, p. 523." — Tk. 



ch. xi] ON HUMAN UNDEKSTANDING 511 

established harmony, that all the monads have received their 
origin from God and depend upon him. But we cannot com- 
prehend the Iioav in detail; and at bottom their conservation 
is nothing else than a continual creation, 1 as the Scholastics 
have very clearly recognized. 



CHAPTEE XI 

OF OUR KNOWLEDGE OF THE EXISTENCE OF OTHER THINGS 

§ 1. Ph. As, then, the existence of God only has a necessary 
connection with ours, the ideas we may have of anything no 
more prove the existence of this thing than the portrait of a 
man proves his existence in the world. § 2. The certainty, 
however, I have of black and white upon this paper by means 
of sensation is as great as that of the motion of my hand, 
which is second only to the knowledge of our own existence, 
and of that of God. § 3. This certainly deserves the name of 
knowledge. For I do not believe that any one can seriously be 
so sceptical as to be uncertain of the existence of things which 
he sees and feels. At least, he who can carry his doubts so 
far will never have any controversy with me, since he can 
never be certain that I say anything contrary to his opinion. 
The perceptions of sensible things § 4. are produced by exter- 
nal causes which affect our senses, for we do not acquire these 
perceptions without the organs, and if the organs sufficed, 
they would always produce them. § 5. Further, I sometimes 
experience the fact that I cannot prevent these ideas from 
being formed in my mind, as, for example, the light, when I 
have my eyes open in a place into which the light may enter : 
while I can lay aside the ideas which are in my memory. 
There must be, then, some external cause of this living im- 
pression whose efficacy I cannot overcome. § 6. Some of these 

1 Of. Observatio ad Recensionem libri de Fidei et Rationis consensu a Do- 
mino Jaqueloto editi, mense Octobri proxime prsecedenti factum, pub. in the 
" Acta Erud. Lips.," Dec. 1705, p. 553, ad fin., Gerhardt, 6, 556-8, Erdmann, 
433-4, Duteiis, 2, Pt. I., 256-8; Theodicee, Pt. III., §§ 382, 385, 391-3, G. 6, 
342, E. 614, Jacques, 2, 290, Janet, 2, 388, Dutens, 1, 387 ; Pichler, Die The- 
ologie des Leibniz, 1, 252, Miinchen, 1869; Monadologie, § 47, G. 6, 614, E. 708, 
Jacques, 2, 397, Janet, 2, 601, trans. Duncan, 225; Nolen, Leibniz, La Mono- 
' dologie, 3d ed., Paris, 1893, pp. 148, 211. — Tr. 



512 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

impressions are produced in us with pain, although afterwards 
we remember it without feeling the least inconvenience. And 
although mathematical demonstrations do not depend on the 
senses, yet the examination made of them by means of dia- 
grams is of much use in proving the evidence of our sight, and 
seems to give to it a certainty approaching that of demonstra- 
tion itself. § 7. Our senses also in many cases bear witness 
to each other. He who sees the fire may feel it if in doubt of 
it. And in writing this, I see that I can change the appear- 
ance of the paper, and say beforehand what new idea it is 
going to present to the mind; but, when these characters are 
traced, I can no longer avoid seeing them as they are, in 
addition to the fact that the sight of these characters will 
make another man utter the same sounds. § 8. If any one 
thinks that all this is but a long dream, he may dream, if he 
pleases, that I make this response to him, that our certainty 
based upon the testimony of our senses is as perfect as our 
nature allows, and our condition demands. He who sees a 
candle burning, and tries the heat of the flame, which hurts 
him if he does not withdraw his finger, will not ask for a 
greater certainty in order to govern his actions, and if this 
dreamer did not so do (i.e. withdraw his finger) he would find 
himself awakened. Such an assurance then suffices us, which 
is also as certain as pleasure or pain, two things beyond which 
we have no interest in knowledge Or the existence of things. 
§ 9. But beyond our actual sensation, there is no knowledge, 
and it is only jdrobability, as when I believe that there are men 
in the world; of which fact there is a high degree of probabil- 
ity, although at present, alone in my chamber, I see none of 
them. § 10. It is also folly to expect a demonstration of every- 
thing and to act not in accord with clear and evident truths 
though they are not demonstrable. A man who should so 
use them could be assured of nothing but of dying in a very 
short time. 

Th. I have already remarked in our preceding conferences 
that the truth of sensible things is justified by their connec- 
tion, 1 which depends upon the intellectual truths grounded in 
reason and upon constant observations in the sensible things 

1 Cf. New Essays, Bk. IV., chap. 2, § 14, Th. (2), ante, p. 422, note 1. From 
the idealistic point of view, the only possible criterion of the truth of the phe- 



ch. xi] ON HUMAN UNDERSTANDING 513 

themselves even when the reasons do not appear. And as 
these reasons and observations give us the means of judging 
the future as related to our interest, and as success corresponds 
with our rational judgment, we could not demand, nor have 
indeed, a greater certainty regarding these objects. We can 
also give a reason for dreams themselves, and for their slight 
connection with other phenomena. Nevertheless, I believe 
that we might extend the appellation of knowledge and of 
certainty beyond actual sensations, since clearness and mani- 
festness go beyond, which I consider as a species of certainty; 
and it would undoubtedly be folly seriously to doubt whether 
there are men in the world when we do not see any. To doubt 
seriously is to doubt in relation to the practical, and we might 
take certainty as a knowledge of truth which we cannot doubt 
in relation to the practical without madness ; and sometimes 
we take it still more generally, and apply it to cases where 
we could not doubt without deserving to be severely blamed. 
But evidence would be a luminous certainty, i.e. where we do 
not doubt because of the connection we see between ideas. 
According to this definition of certainty, we are certain that 
Constantinople is in the world, that Constantine, Alexander 
the Great, and Julius Csesar lived. It is true that some peas- 
ant of Ardennes might justly doubt about these, for lack of 
information; but a man of letters and of the world could not 
do so without great derangement of mind. 

§ 11. Ph. We are assured in truth by our memory of many 
things which are past, but we shall not be able to judge easily 
whether they exist still. I saw yesterday water, and a certain 
number of beautiful colors upon bubbles formed upon this 
water. Now I am certain that those bubbles as well as that 
water existed, but I do not know with any more certainty the 
present existence of the water than that of the bubbles, 
although the former is infinitely more probable because the 
water has been observed to be lasting and the bubbles to dis- 
appear. § 12. Finally, outside of ourselves and God we know 
other spirits only by revelation, and we have concerning them 
only the certainty of faith. 

nomena of the senses is the constancy and regularity in their connection or 
consecution. Cf. also Be modo distinguendi phienomena realia ab imagina- 
riis, Gerhardt, Leibniz, philos. Schrift., 7, 319 sq. ; Erdmann, 443-445. — Tr. 

2 l 



514 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

Th. It lias already been remarked that our memory some- 
times deceives us. And we put confidence in it or not, accord- 
ing as it is more or less vivid, and more or less connected with 
the things we know. And even when we are assured of the 
principal fact we may often question the circumstances. I 
remember to have known a certain man, for I feel that his 
image as well as his voice is not new to me; and this double 
indication is a better guarantee to me than one of the two, but 
1 cannot remember where I have seen him. It happens, how- 
ever, though rarely, that a person is seen in a dream before he 
is seen in flesh and blood. And I am assured that a lady of a 
well-known court saw in a dream and described to her friends 
the person she afterwards married, and the hall in which the 
betrothal was celebrated, and she did this before she had seen 
or known either the man or the place. They attributed the 
circumstance to some indefinite secret presentiment; but 
chance may produce this effect, since it is quite rare that it 
happens, besides, dream-images being somewhat obscure, there 
is more liberty in connecting them afterwards with certain 
others. 

§ 13. Ph. Let us conclude that there are two kinds of prop- 
ositions, the one particular and concerning existence, as, for 
example, that an elephant exists ; the other general, concern- 
ing the dependence of ideas, as, for example, that men should 
obey God. § 14. The majority of these general and certain 
propositions bear the name of eternal truths, and, in fact, they 
all are such. This is not because these are propositions act- 
ually formed somewhere from all eternity, or because they 
are graven upon the mind after some model, which always 
existed, but because we are assured that when a creature en- 
riched with faculties and means therefor, applies his thoughts 
to the consideration of his ideas, he will discover the truth 
of these propositions. 

Th. Your division appears to return to mine of propositions 
of fact and propositions of reason. Propositions of fact also 
may become general in a way, but it is by induction or obser- 
vation, so that it is only a multitude of similar facts, as when 
it is observed that all quicksilver is evaporated by the force 
of fire; and this is not a perfect generality, because we do 
not see its necessity. General propositions of reason are 



ch.xi] ON HUMAN UNDERSTANDING 515 

necessary, although the reason also furnishes some which are 
not absolutely general, and are only probable, as, for example, 
when we presume an idea to be possible until its contrary is 
discovered by a more exact research. There are finally mixed 
propositions, drawn from premises, some of which come from 
facts and observations, and others are necessary propositions; 
and such are a number of geographical and astronomical con- 
clusions regarding the globe of the earth and the course of the 
stars, which spring from the combination of the observations 
of travellers and astronomers with the theorems of geometry 
and arithmetic. But as, according to the usage of logicians, 
the conclusion folloivs the weakest of the premises x and cannot 
have more certainty than they, these mixed propositions have 
only the certainty and generality which belong to the obser- 
vations. As for the eternal truths, it must be observed that at 
bottom they are all conditional and say in effect : such a thing 
posited, such another thing is. For example, in saying: every 
figure which has three sides will also have three angles, I say 
nothing else than that, supposing there is a figure with three 
sides, this same figure will have three angles. 1 say this 
same, and it is in this respect that the categorical proposi- 
tions which may be stated unconditionally, although at bot- 
tom conditional, differ from those called hypothetical, as this 
proposition would be: if a figure has three sides, its angles are 
equal to two right angles, in which we see that the antecedent 
proposition (viz. : the figure of three sides) and the consequent 
(viz. : the angles of the figure of three sides are equal to two 
right angles) have not the same subject as they have in the 
preceding case, in which the antecedent was : this figure has 

1 The variously phrased formula : conclusio sequitur partem debiliorem or 
deteriorern ; sectetur partem conclusio deteriorem ; pejorem sequitur semper 
conclusio partem, is the Scholastic expression of the fundamental principle of 
the categorical syllogism, according to which the conclusion cannot contain 
more than is contained in the premises, or, as given by Hamilton (Lects. on 
Logic, p. 219, Boston, 1873), in his third rule of the syllogism, "The conclu- 
sion must correspond in quantity with the subsumption [minor premise], and 
in quality with the sumption [major premise]." Logicians regarded negative 
and particular propositions as weaker or worse as related to universal and 
affirmative propositions, the negative being weaker in quality and the par- 
ticular in quantity, so that in the syllogism if one of the premises is particular 
the conclusion will be particular, and if one of the premises is negative the 
conclusion will be negative. For the history of the subject, cf. Prantl, Gesch. 
d. Logik, 1, 371, 587 ; 2, 275 ; 3, 48. — Te. 



51G LEIBNITZ'S CEITIQUE OF LOCKE [bk. iv 

three sides, and the consequent: the said figure has three angles. 
Although, again, the hypothetical may often be transformed 
into the categorical, merely by changing a little the terms, 
as if instead of the preceding hypothetical, I said : the angles 
of every figure with three sides are equal to tivo right angles. 
The Scholastics have hotly disputed de constantia subjecti, as 
they called it, i.e. how the proposition made upon a subject 
can have a real truth, if this subject does not exist. The fact 
is that the truth is only conditional, and says, that in case the 
subject ever exists, it will be found such. But it will be 
further demanded, in what is this connection founded, since 
there is in it some reality which does not deceive. The reply 
will be, that it is in the connection of ideas. But it will be 
asked in reply, where would these ideas be if no mind existed, 
and what then would become of the real ground of this cer- 
tainty of the eternal truths? This leads us finally to the ulti- 
mate ground of truths, viz. : to that Supreme and Universal 
Mind, which cannot fail to exist, whose understanding, to 
speak truly, is the region of eternal truths, as St. Augustine 
has recognized and expresses in a sufficiently vivid way. 1 And 
in order not to think that it is unnecessary to recur to this, 
we must consider that these necessary truths contain the de- 
termining reason and the regulating principle of existences 
themselves, and, in a word, the laws of the universe. Thus 
these necessary truths being anterior to the existence of 
contingent beings, must be grounded in the existence of a 

1 Aurelius Augustinus, 354-430, grounded his philosophy in the principle of 
the ahsolute and immediate certainty of consciousness or inner experience. 
Cf. De Beata Vita, chap. 7 ; Solil. II., 1 (ante, p. 410, note 1) ; De Vera Relig., 39, 
72 sq. ; De Trin., X., 14, XIV., 7. In this certainty of the individual conscious- 
ness, i.e. in thought itself, is immediately involved the idea of God in whom 
exist the universal truths as the ideas or norms of all reality. Cf. De Icleis, 2 : 
" Sunt namque ideae principales formse quaedam, vel rationes rerum stabiles et 
incommutabiles, qua? ipsae formatae non sunt atque per hoc aeternae ac semper 
eodem modo se habentes, quae in divina intelligentia continentur, et quum 
ipsae neque oriantur neque intereant, secundum eas tamen formari dicitur 
omne, quod interire potest et omne, quod oritur et interit." 

For a good account of Augustine's philosophy, cf. Ueberweg-Heinze, 7th 
ed., Berlin, 1888, 2, 97-115, especially 106-7, Eng. trans, from 4th Germ, ed., 
New York, 1871, 1, 333 sq., especially 339-40; Windelband, Hist, of Philos., 
trans, by Tufts, 276 sq. Augustine's works form Vols. 32-47 of the Latin 
Fathers in Migne, Patrol, cur. compl., Paris, 1835 sq.; Eng. trans, by Dods, 
15 vols., Edinburgh, 1871-77, and in Schaff's lib. Nicene and Post-Nicene 
Fathers, Vols. 1-8, Buffalo, 1886-88. — Tr. 



ch. xn] ON HUMAN UNDERSTANDING 517 

necessary substance. Here it is that I find the original of the 
ideas and truths which are graven in our souls, not in the 
form of propositions, but as the sources out of which applica- 
tion and occasion will cause actual judgments to arise. 1 



^CHAPTER XII 

OF THE IMPROVEMENT OF OUR KNOWLEDGE 

§ 1. Ph. We have spoken of the kinds of knowledge we 
have. Now let us come to the means of improving the knowl- 
edge or of finding the truth. It is the received opinion among 
scholars, that the maxims are the bases of all knowledge, and 
that each particular science is based upon certain things 
already known (prazcognita). § 2. I admit that mathematics 
seem to favor this method by their good success, and you have 
given considerable support to this view. But it is still doubtful 
whether it is not rather the ideas which were of service therein 
through their connection thau two or three general maxims 
which were posited at the beginning. A young lad knows 
that his body is greater than his little finger, but not by vir- 
tue of this axiom, that the whole is greater than its part. 
Knowledge commenced by particular propositions; but after- 
wards it was desired to relieve the memory by means of gen- 
eral notions from a cumbersome load of particular ideas. If 
language were so imperfect that there were no relative terms, 
zvhole and part, could he not know that his body is larger than 
his little finger? I at least give you the reasons of my author, 
although I think I foresee what you will say thereto in con- 
formity with what you have already said. 

Th. I know not why you bear the maxims such ill will as 
to attack them yet again ; if they serve to relieve the memory 
of a multitude of particular ideas, as you admit, they must be 
very useful, although they had no other use. But I add that 



1 For Leibnitz God is the source of all truths as well as of all beings. The 
idea of God contains in itself potentially all truth, and is the regulative (but 
not in the Kantian sense of the term), or better, the constitutive, principle 
of all thought, just as his actuality contains potentially within itself all exist- 
ences, and is the regulative, i.e., constitutive, principle of all being. Cf. also, 
ante, p. 496, note 1. — Tr. 



518 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

they do not spring from particular ideas, for they are not 
found by induction from examples. He who knows that ten 
is more than nine, that the body is larger than the finger, and 
that the house is too large to be able to run away with the 
door, knows each one of these particular propositions, by one 
and the same general reason which is, as it were, incorpo- 
rated therein and illuminated, just as we see designs adorned 
with colors in which the proportion and configuration con- 
sists properly in the outlines, whatever the color may be. 
Now this common reason is the axiom itself which is known, 
so to speak, implicitly, although it does not exist at first in an 
abstract and separate manner. The examples derive their 
truth from the incorporated axiom, and the axiom has not its 
ground in the examples. And as this common reason of these 
particular truths exists in the minds of all men, you see clearly 
that it is not necessary that the words ivhole and part be found 
in the language of him who is imbued therewith. 

§ 4. Ph. But is it not dangerous to authorize assumptions 
under the pretext of axioms? One will assume, with some of 
the ancients, that all is matter ; another, with Poiemo, 1 that 
the world is God ; a third will assert that the sun is the prin- 
cipal divinity. Judge what a religion we should have, if that 
were allowed. ; So true is it that it is dangerous to receive 
principles without questioning them, especially if they con- 
cern morality. For some one will expect another life, like 
that of Aristippus, 2 who placed happiness in the pleasures of 
the body, rather than like that of Antisthenes, 3 who main- 

1 Poiemo, the successor of Xenocrates, 396-314 B.C., as scholarch, or head, 
314-270 B.C., of the school of the Old Academy, and the third in that office 
from Plato (Speusippus holding it from Plato's death in 347 to 339, and Xeno- 
crates from 339-314), devoted himself chiefly to ethics. The statement that he 
declared the universe to he God — noAe/nov rbv koct/jlov 9ebv air^vaTo — rests on 
the authority of Stobaeus, JEclogse phys., Bk. I., chap. 2, 5, § 62, p. 15, ed. A. 
Meineke, Leipzig, 1855-64. For his philosophy, cf. Zeller, Philos. d. Griech., 
II., 1 [Vol. 3], 993-4, 1045-3, 4th ed., Leipzig, 1889. — Tr. 

2 Aristippus, c. 435-c. 366 B.C., the founder of the Cyrenaic school, made 
pleasure, which, according to Diog. Laertius, II., 85, 86, he defined as the 

feeling of a gentle motion — TeAos 5' atti^aive ttjv \elav K Lvq<Ti.v eis ala-Brio-tv ZvaSiSo- 

fiev-qv ... Tj)>' ju.ev AeiW Ktvrjan.v tijv rfSov^v — the end of life, the wise man aiming 
to enjoy pleasure without heing controlled by it. For his writings, cf. Mul- 
lach, Fragt. philos. Gr., II., 397 sq. On his life and philosophy, cf. Zeller, 
Philos. d. Griech., II., 1 [Vol. 3], 336 sq., ethical doctrine, 352 sq. — Tr. 

3 Antisthenes, c. 440-c. 369 B.C., a pupil of Gorgias and Socrates, was the 
founder of the Cynic school, and taught, according to Diog. Laertius, VI., 11, 



ch. xii] ON HUMAN UNDERSTANDING 519 

tained that virtue suffices to produce happiness.- And Arche- 
laus, 1 who will lay it down as a principle that justice and 
injustice, honesty and dishonesty, are defined only by the laws 
and not by nature, will no doubt have other measures of moral 
good and evil than those who admit obligations anterior to 
human constitutions. § 5. It must be, then, that principles are 
certain. § 6. But this certainty comes only from the com- 
parison of ideas : thus we have no need of other principles, 
and according to this rule alone we shall advance much farther 
than by putting our minds at the disposal of another. 

Th. I am astonished, sir, that you turn against maxims, i.e. 
against evident principles, that which can and must be said 
against principles assumed gratis. When one demands prce- 
cognita in the sciences, or anterior knowledge, which serves 
to ground science, he demands known principles and not arbi- 
trary positions, whose truth is not known; and even Aristotle 
understands that the inferior and subaltern borrow their prin- 
ciples from other superior sciences in which they have been 
demonstrated, except the first of the sciences, which we call 
metaphysics, which, according to him, asks nothing from the 
others, and furnishes them the principles they need; and 
when he says: Set Tuo-rtvaiv tov ixavOdvovra, 2 the apprentice must 

that virtue only is a good, and that it is sufficient for happiness — avTdpKt] yap 
Trjc apeTifv elvau irpbs evSaip-oviav. For his writings, cf. Mullach, Fragt. philos. 
Gr., II., 261 sq. On his life and philosophy, cf. Zeller, Philos. d. Griech., II., 1 
[Vol. 3], 281 sq., ethical doctrine, 303 sq. — Tr. 

1 Archelaus, the dates of whose birth and death are unknown, was a physi- 
cist, and the disciple of Anaxagoras, c. 500-428 B.C., whose physical doctrine 
he seems to have modified in the direction of the Ionic school as represented 
by Anaximines, c. 588-c. 524 B.C., and Diogenes of Apollonia. Zeller says that 
the statement, as given by Diog. Laertius, II., 16, that he derived the distinc- 
tion of good and bad from custom rather than nature — to SUaiov elvai «ai to 
ai<rxpbv ov tfrvaei akKi v6p-ta — appears to be due to a mistake in interpreting his 
language, and that he merely said that men at the beginning were without 
custom and law, and first attained thereto in the course of time. On his 
philosophy, cf. Zeller, Philos. d. Griech., I., 2 [Vol. 2], 1031-1038, 5th ed., 
Leipzig, 1892. — Tb. 

2 Cf. Aristotle, Sophist. Elench., chap. 2, 161, b, 1-3: SiSao-KaKiKol p.kv ol e« 

Tuiv oiKeiuiv apxi>f e/cacrTou p-adrjixaTos (cat ovk 6k to>v tov anOKpivop.evov &o££iv cruAAoyifd- 

p.evoi. (Selyap Trio-Tfuetf tov p.av9*vovTo.) , i.e. discussions for the purpose of teach- 
ing proceed from the special principles of each science, and do not draw their 
conclusions from the opinions of the participating pupil ; Aristotle's thought 
being that the pupil will receive a confirmation of the mere faith in the prin- 
ciples demanded of him at the outset, in the course of the explanation and 
demonstration of these principles in his presence, and in the agreement of the 
scientific results with the facts and his further knowledge. Leibnitz here 



520 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

believe his master, his thought is that he must do it only while 
waiting, while he is not yet instructed in the higher sciences, 
so that it is only provisionally. "Thus we are very far from 
receiving gratuitous principles. To this it must be added that 
even principles whose certainty is not complete may have 
their use if we build upon them only by demonstration; for 
although all the conclusions in this case are conditional only, 
and are valid only upon the supposition that this principle is 
true, nevertheless this connection itself and these conditional 
enunciations would at least be demonstrated ; so that it were 
much to be desired that we had many books written in this 
way, where there would be no danger of error, the reader or 
disciple being warned of the condition. And practice will be 
regulated by these conclusions only as the supposition shall 
be found verified elsewhere. This method also serves very 
often itself to verify suppositions or hypotheses, when many 
conclusions arise from them, the truth of which is otherwise 
known, and sometimes this gives a perfect proof (retour) 
sufficient to demonstrate the truth of the hypothesis. Mr. 
Conring, 1 a physician by profession, but a clever man in every 
kind of learning, except perhaps mathematics, wrote a letter 
to a friend engaged in reprinting at Helmstadt the book of 
Viottus, 2 an esteemed Peripatetic philosopher who tried to 

expresses a similar thought, in premising the provisional character of that 
faith which the beginner should have in his teacher. — Tr. 

1 Hermann Conring, 1606-1681, one of the most learned men of his age, 
possessed of vast erudition, and thoroughly informed on medicine, law, the- 
ology, history, physics, philology, etc., taught at Helmstadt, and wrote an 
immense number of works, which have been united in part and published 
under the title of Opera omnia, Brunswick, 1730, 7 vols., fol. For an account 
of him, cf. Michaucl, Biog. Univ., Vol. 9, pp. 447-452. For his correspondence 
with Leibnitz, cf. Gerbardt, Leibniz, philos. Schrift., 1, 153-206. — Tr. 

2 Bartolommeo Viotto, or Viotti, surnamed a Clivolo, son of a distin- 
guished surgeon, Tommaso Viotto, who was the first in the University of 
Turin to receive the laurel crown in surgery from the Decurions of Trino, 
was a philosopher and physician of Turin, and, in the five years preceding 
1552, public professor of logic in that city. He died in 1568. He was author 
of Be balneorum naturalium viribus lib. IV., Lugduni, 1552, reprinted in Be 
balneis omnia quse extant apud Grsecos, Latinos, et Arab as, fol. Venetiis, 1553, 
pp. 247-71 ; arid of the work here and elsewhere referred to by Leibnitz, 
Bemonstrationwn in methodum medendi lib. V., 8vo, Parisiis, 1560, and under 
the editorship of A. Frolingius, Helmstadt, 1661, Braunschweig, 1684. Cf. 
Correspondence of Leibnitz and Conring, Gerbardt, Leibniz. philos. Schrift., 
1, 184, 187; of Leibnitz and Placcius, Dutens, Leibnit. op. om., 6, 45. 

Conring, Introd. in univ. art. med., Halre et Lipsiae, 1726, p. 23, says of 



en. xii] ON HUMAN UNDERSTANDING 521 

explain the demonstration and "Posterior Analytics" of 
Aristotle. This letter was appended to the book, and in 
it Conring criticised Pappus when he said that analysis 
proposes to discover the unknown by assuming it, and by 
reaching therefrom, by inference, known truths ; x a method 
which is contrary to logic (he said) which teaches that from 
falsehood we cannot infer truths. But I made known to him 
afterwards that analysis makes use of definitions and other 
reciprocal propositions which furnish means of making the 
proof (retour), and of discovering synthetic demonstrations. 2 
And even when this proof is not demonstrative, as in physics, 
it is nevertheless sometimes highly probable, when the hy- 
pothesis explains easily many phenomena, difficult without 
it and very independent of one another. I hold to the 
truth, sir, that the principle of principles is in a way the 
good use of ideas and of experience; but by examining it 
thoroughly we shall find that, as regards ideas, it is nothing 
else than the union of definitions by means of identical axi- 
oms. Nevertheless, it is not always an easy thing to come to 
this ultimate analysis, and whatever desire the geometers, at 
least the ancient geometers, have shown to succeed therein, 
they have not yet been able to do so. The celebrated author 

him : " Certe qui necessitatem ejus in medicina sirnul et ipsam artem demon- 
strandi post Galenum ostenderit, hactenus nemo inventus est, si excipias 
unum Bartholomseum Viottum honiinem longe doctissimum ; cujus de demon- 
stratione prteclarum opus ante centum annos prodiit." Cf., also, G. Pasch, 
De novis inventis, 2d ed., 4to, Lipsise, 1700, p. 26; J. A. van der Linden, De 
scriptis medicis, 8vo, Amstelredami, 1637, p. 82, Linden, renovat., 4to, Norim- 
bergre, 1686, pp. 114, 119 ; Kestner, Medicinisches-Gelehrten-Lexicon, 4to, Jena, 
1740, p. 897 ; G. G. Bonino, Biografia medica piemontese, 8vo, Torino, 1824, 
Vol. 1, pp. 199-201. — Tr. 

1 Pappus of Alexandria was a Greek geometer " of a very high order," who 
flourished, according to the best recent opinion, in the reign of Diocletian, 
284-305, and whose Sura-ywyjj, or Collection, is of very great value in the his- 
tory of mathematics. From Bk. VII. of this work is derived a large part of 
our knowledge of Greek geometry. The best ed. of the whole work is F. 
Hultsch, Pappi Alexandrini Collectionis quw supersunt, 3 vols., Berlin, 1876-78. 

Pappus' explanation of the nature of analysis and synthesis, which Con- 
ring erroneously criticised, is found in the preface of Bk. VII. of the 2vvay&>y)j, 
cf. Hultsch, op. eit., Vol. 2, pp. 634-6; C. I. Gerhardt, Der Sammlung des 
Pappus von Alexandrien, siebentes u. achtes Buch, Halle, 1871, pp. 2-4. Ac- 
cording to Schaar schmidt, this explanation is perhaps the clearest and best 
concise statement that has been made of the nature of the analytic and syn- 
thetic method. — Tr. 

2 Cf. Correspondence of Leibnitz and Conring, Letter of Jan. 3d, 1678, 
Gerhardt, Leibniz, philos. Schrift., 1, 187-8; also, ibid., 185, 190, 193 sq. — Tr. 



522 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

of " Tlie Essay on Human Understanding," would give them 
much pleasure if he would complete this investigation, a little 
more difficult than we think. Euclid, for example, has put 
among the axioms one which amounts to saying: that two 
straight lines can meet only once. The image derived from 
the experience of the senses, does not permit us to picture to 
ourselves more than one meeting of the two lines ; but it is 
not upon this that science must be founded. And if any one 
believes that this image gives the connection of distinct ideas, 
he is not sufficiently instructed concerning the source of truths, 
and a multitude of propositions, demonstrable by others ante- 
rior, would pass with him as immediate. Many of those who 
have criticised Euclid, have not sufficiently considered this: 
these kinds of images are only confused ideas, and he who 
knows the straight lines only by this means will not be capable 
of demonstrating anything.* 7 Euclid, therefore, for want of a 
distinctly expressed idea, i.e. a definition of a straight line (for 
that which he gives meanwhile is obscure and of no use to him 
in his demonstrations), was obliged to return to two axioms 
which for him took the place of definitions and which he em- 
ployed in his demonstrations : the one that two straight lines 
have no common part, the other that they enclose no space. 
Archimedes has given a kind of definition of the straight line, 
in saying that it is the shortest line between two points. But 
he tacitly assumes (by employing in his demonstrations ele- 
ments like those of Euclid, based upon the two axioms I have 
just mentioned) that the properties (affections) of which these 
axioms speak, accord with the line which he defines. 1 Thus if 
you believe, with your friends, under the pretext of the agree- 
ment or disagreement of ideas, that what these images tell us 
was allowed and is still to be received in geometry, without 
seeking that strictness of demonstration by means of defini- 
tions and axioms which the ancients demanded in this science 
(as I believe many people will believe for lack of information), 
I will admit, sir, that you may be contented as regards those 
who trouble themselves only about practical geometry such 
as it is, but not as regards those who desire to have the science 
which serves indeed to perfect the practical. And if the 
ancients had been of this opinion and had relaxed their efforts 
1 Gerliardt and Erdmann read " definit " ; Jacques " decrit." — Tb,. 



ch. xii] ON PIUMAN UNDEESTANDING 523 

on this point, I think they would have made but little advance, 
and would have left us only an empirical geometry such as 
that of the Egyptians apparently was, and such as that of the 
Chinese seems still to be; this would have deprived us of the 
most worthful physical and mechanical knowledge which 
geometry has caused us to discover, and which is unknown 
wherever our geometry is unknown. It is also apparent 
that in following the senses and their images we should fall 
into errors ; much the same as we see that all those who are 
not instructed in exact geometry receive as an indubitable truth 
upon trust in their imagination, that two lines continually 
approaching each other, must finally meet; while geometers 
give contrary instances in the case of certain lines called 
asymptotes. But besides this we should be deprived of what 
I value most highly in geometry as related to reflection, viz. : 
permitting us to catch a glimpse of the true source of eternal 
truths and of the means of making us comprehend their neces- 
sity, a matter which the confused ideas of the sense-images 
could not show us distinctly. You will say to me that Euclid 
was obliged, however, to confine himself to certain axioms 
whose evidence is seen only confusedly by means of the 
images. I agree with you that he has limited himself to these 
axioms, but it was better for him to limit himself to a small 
number of truths of this nature which appeared to him the 
simplest and to deduce from them the others which another 
less exact would also have taken as certain without demonstra- 
tion, than to leave many of them undemonstrated, and what is 
worse, to allow people the liberty of extending their laxity 
according to their fancy. You see then, sir, that what you 
and your friends have said regarding the connection of ideas 
as the true source of truths needs explication. If you are 
willing to content yourself with the confused sight of this 
connection, you weaken the exactness of demonstrations, and 
Euclid has done incomparably better in reducing all to defini- 
tions and to a small number of axioms. Yet if you wish this 
connection of ideas to be distinctly seen and expressed, you 
will be obliged to recur to definitions and identical axioms, 
as I claim; and sometimes you will be obliged to content 
yourself with some axioms less primitive, as Euclid and 
Archimedes have done, when you find difficulty in attaining a 



524 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

perfect analysis, and yon will do better in that way than to 
neglect or defer some fortunate discoveries which you can 
already make by their means : as in fact I have already said 
to you at another time, sir, that I believe we should not have 
a geometry (I mean a demonstrative science), if the ancients 
had not been willing to advance until they had demonstrated 
the axioms they were obliged to employ. 

§ 7. Ph. I begin to understand what a distinctly known con- 
nection of ideas is, and I see clearly that in this sense axioms 
are necessary. I see clearly also how necessary it is that the 
method we follow in our researches, when the question is that 
of the examination of ideas, be regulated by the example of 
the mathematicians who from certain very clear and easy 
beginnings (which are nothing else than the axioms and defi- 
nitions) proceed by small degrees and a continual chain of 
reasoning to the discovery and demonstration of truths that 
appear at first beyond human capacity. The art of finding- 
proofs, and these admirable methods they have invented for 
separating and putting in order mediate ideas is what has 
produced such wonderful and unexpected discoveries. But 
whether with time a similar method may not be found out 
useful in respect to other ideas as well as those belonging to 
magnitude is a question I will not determine. At least, if 
other ideas were examined according to the ordinary method 
of the mathematicians, they would lead our thoughts farther 
than we are perhaps led to imagine. § 8. And this might be 
done particularly in the case of morality, as I have more than 
once said. 

Th. I believe you are right, sir, and I have been disposed 
for a long time to make it my business to accomplish your 
predictions. 

§ 9. Ph. In regard to the knowledge of bodies we are com- 
pelled to take a directly contrary path; for having no ideas 
of their real essences, we are obliged to recur to experience. 
§ 10. But I do not deny that a man accustomed to making 
rational and regular experiments is capable of forming juster 
conjectures regarding their still unknown properties than 
another not so accustomed, but it is judgment and opinion, not 
knowledge and certainty. This makes me think that physics 
is incapable of becoming a science in our hands. But experi- 



en. xn] ON HUMAN UNDERSTANDING 525 

rnents and historical observations may be of use to us as 
regards the health of our bodies and the conveniences of life. 

Th. I admit that physics as a whole will never be a per- 
fect science among us, but we shall not cease to be able to 
have some physical science, and indeed we have already some 
specimens of it. For example, magnetology may pass for 
such a science, for, making a few suppositions based upon 
experience, we can demonstrate from them by a certain infer- 
ence a number of phenomena which really occur as we see that 
reason declares. We ought not to hope to give a reason for 
all experiments, as indeed the geometers have not yet proved 
all their axioms ; but just as they are satisfied to deduce a 
large number of theorems from a small number of principles 
of the reason, so is it sufficient that the physicists by means 
of certain principles of experience give a reason for a multi- 
tude of phenomena and can indeed prove them in practice. 

§ 11. Ph. Since then our faculties are not fitted to make us 
discern the internal fabric of bodies, we must consider that it 
is enough that they discover to us the existence of God, and a 
sufficiently extended knowledge of ourselves to instruct us in 
our duties and in our greatest interests, particularly as related 
to eternity. And I think I am right in inferring therefrom 
that morality is the proper science and the important business of 
mankind in general, as, on the other hand, the different arts which 
are conversant about different parts of nature are the lot of par- 
ticular men. It may be said, for example, that ignorance of 
the use of iron is a reason in the countries of America, where 
nature has spread abroad abundantly all kinds of goods, for the 
lack of the greatest part of the conveniences of life. Thus 
very far from despising the science of nature, § 12. I hold, 
that if this study is directed, as it ought to be, it may be of 
greater use to the human race than all that has been done up 
to this time ; and he who invented printing, who discovered 
the use of the compass, and who made known the virtue of 
quinquina, has contributed more to the propagation of knowl- 
edge and to the advancement of the useful conveniences of 
life, and has saved more people from the grave, than the 
founders of colleges and hospitals and other monuments of 
the most exemplary charity, which have been built at great 
expense. 



526 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 



Th. You could say nothing, sir, more to my liking. True 
morality or piety, very far from favoring the inactivity of cer- 
tain idle quietists, must impel us to cultivate the arts. And 
as I said not long since, a better police would be able to bring 
us some day a much better medical science than that we have 
at present. We cannot preach this doctrine enough, next to 
the care for virtue. 

§ 13. Ph. Although I recommend experiments, I do not 
despise probable hypotheses. They may lead us to new dis- 
coveries, and are, at least, a great aid to the memory. But 
our mind has a great tendency to go too fast and to be satis- 
fied with certain superficial appearances, for lack of taking 
the necessary time and trouble to apply them to a multitude 
of phenomena. 

Th. The art of discovering the causes of phenomena, or 
true hypotheses, is like the art of deciphering, in which an 
ingenious conjecture often greatly shortens the road. Lord 
Bacon began to put the art of experimenting into precepts, 
and Chevalier Boyle * had a great talent for practising it. 
But if the art of employing experiments and of drawing con- 
sequences therefrom is not joined with it, we shall never 
with the utmost cost attain to what a man of great penetration 
might discover at first sight. Descartes, assuredly such a man, 
has made a similar remark in one of his letters 2 regarding the 
method of the Chancellor of England; and Spinoza (whom I 
do not hesitate to quote when he says a good thing) in one of 
his letters 3 to the late Mr. Oldenburg, Secretary of the Boyal 
Society of England, printed among the posthumous works of 
this subtle Jew, makes a similar reflection upon a work of 
Boyle, who, to speak the truth, stops a little too much to 
draw from a great number of fine experiments no other con- 

1 Cf. ante, p. 324, note 2. — Tr. 

2 The remark here referred to by Leibnitz as occurring in one of Descartes' 
letters has not as yet been found in any of those now extant ; and, as mention 
is made of Bacon in Spinoza's remark cited immediately after, it is possible 
that Leibnitz confounded the two authors, a thing which might readily happen, 
especially as Leibnitz was often out of the reach of books when composing 
his works, as probably in this case, cf. ante, p. 8, note 1. — Tr. 

3 Of. Spinoza, Opera, ed. Van Vloten and Land, 2, 19 : " Sed interim nescio, 
cur clarissimus vir hoc" (i.e. universal mechanism) " adeo sollicite conetur 
colligere ex hoc suo experimento ; cum jam hoc a Verulamio, et postea a 
Cartesio satis superque demoustratum sit." — Tr. 



ch. xn] ON HUMAN UNDEESTANDING 527 

elusion than this which he might take as a principle, viz. : that 
everything in nature takes place mechanically, a principle 
which can be rendered certain by reason alone, and never by 
experiments, whatever their number. 

— § 14. Ph. After having established clear and distinct ideas 
with fixed names, the great means of extending our knowl- 
edge is the art of finding mediate ideas which can show us the 
connection or incompatibility of the extreme ideas. The max- 
ims at least are of no avail in furnishing them. Suppose a 
man has not an exact idea of a right angle, he will vainly tor- 
ment himself in demonstrating something about the right- 
angled triangle : and whatever maxims he employs, he will have 
difficulty in attaining by their aid the proof that the first 
squares of the sides enclosing the right angle are equal to the 
square on the hypothenuse. A man might ruminate upon 
these axioms a long time without ever seeing more clearly 
into mathematics. 

Th. It is of no avail to ruminate upon the axioms without 
having something to which to apply them. Axioms often 
serve to connect ideas, as, for example, this maxim, that similar 
extensions of the second and third dimensions are in reason 
double and triple the corresponding extensions of the first 
dimension, is of very great use; and the quadrature, for ex- 
ample, of the lune of Hippocrates 1 springs from it at once in 
the case of the circles by uniting therewith the application of 
these two figures the one to the other, when their given posi- 
tion furnishes the opportunity for so doing, as their known 
comparison promises light thereupon. 

1 Hippocrates of Chios, c. 440 B.C., a contemporary of Hippocrates of Cos, 
the physician (c/. ante, p. 476, note 2), was a celebrated Greek geometer, whose 
most noted achievement was the discovery of the quadrature of the lune, or 
the crescent-shaped plane figure produced by drawing two perpendicular radii 
in a circle and describing upon the line joining their extremities a semicircle. 
This lune is famous as the first curvilinear space whose area was exactly de- 
termined, and its area is exactly equal to that of the triangle formed by the two 
radii and the line joining their extremities. For the demonstration of this, 
cf. Larousse, Grande Diet. Univ. de XIX e Siecle, Vol. 10, p. 791, a, b. On 
Hippocrates and his services to mathematics, cf. Allman, Greek Geom. 
from Thales to Euclid, 64 sq.; Gow, A Short Hist, of Greek Math., 164 sq.; 
H. Suter, Gesch. d. math. Wissenschaften, 2d ed., Vol. 1, pp. 33-36, Zurich, 
1873. — Tr. 



528 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

CHAPTER XIII 

OTHER CONSIDERATIONS CONCERNING OUR KNOWLEDGE 

§ 1. Ph. It will be perhaps further appropriate to add, that 
our knowledge has a close relation to our sight in this, as well 
as in other things, that it is neither wholly necessary nor wholly 
voluntary. We cannot fail to see when our eyes are open to 
the light, but we can turn them towards certain objects, § 2. 
and consider them with more or less application. Thus when 
the faculty is once applied, it does not depend upon the will 
to determine the knowledge; no more than a man can prevent 
himself from seeing what he sees. But he must employ his 
faculties, as it is necessary in order to inform himself. 

Th. We have spoken before of this point, and established 
the fact that it does not depend upon man to have this or that 
opinion in the present state, but it depends upon him to pre- 
pare himself to have it or not to have it eventually, and that 
thus opinions are voluntary only in an indirect manner. 

CHAPTER XIV 

OF JUDGMENT 

§ 1. Ph. Man would be found without direction in the 
greater part of the arts of his life, if he had nothing to con- 
duct him from the point where certain knowledge fails him. 
§ 2. He must often be contented with a simple twilight of prob- 
ability. § 3. The faculty of using this is judgment. One is 
contented with it often of necessity, but often through want 
of diligence, patience, and skill. § 4. It is called assent or 
dissent, and is employed when anything is presumed, i.e. when 
it is taken as true before it is proved. When this is done con- 
formably to the reality of things, it is a right judgment. 

Th. Others call judgment the act which is performed every 
time a statement is made after some knowledge of a cause; 
and there will be some also who will distinguish judgment 



chs. xm-xv] ON HUMAN UNDERSTANDING 529 

from opinion, as not of necessity being so uncertain. But I 
do not wish to criticise any one regarding the use of words, 
and it is allowed you, sir, to take judgment as a probable 
opinion. As for presumption, which is a term of the juris- 
consults, good use with them distinguishes it from conjecture. 
It is something more, something which must pass for truth 
provisionally until there is proof of the contrary, while a 
sign, a conjecture, must often be weighed against another con- 
jecture. Thus it is that he who admits having borrowed 
money from another, is presumed to pay the debt, unless he 
shows that he had done so already, or that the debt ceases by 
some other principle. Presumption is not then in this sense 
taking before proof, which is not allowed, but taking in advance 
but with foundation, while awaiting a contrary proof. 



CHAPTEE XV 

OF PROBABILITY 

§ 1. Ph. If demonstration shows the connection of ideas, 
probability is nothing else than the appearance of this connec- 
tion based upon proofs in which immutable connection is not 
seen. § 2. There are several degrees of assent from assurance 
down to conjecture, doubt, distrust. § 3. When there is cer- 
tainty, there is intuition in all parts of the reasoning which 
show its connection; but what makes me believe is some- 
thing extraneous. § 4. Now probability is grounded in its 
conformity with what we know, or in the testimony of those 
who know. 

Th. I prefer to maintain that it is always grounded in like- 
lihood (yraisemblance) or in conformity with the truth; and 
the testimony of another is also a thing which the truth has 
been wont to have for itself as regards the facts that are 
within reach. It may be said then that the similarity of the 
probable and the truth is taken either from the thing itself, 
or from some extraneous thing. The rhetoricians employ two 
kinds of arguments: the artificial, drawn from things by rea- 
soning, and the non- artificial, based only upon the express 
testimony either of man or perhaps also of the thing itself. 



530 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

But there are mixed arguments also, for testimony may itself 
furnish a fact which serves to form an artificial argument. 

§ 5. Ph. It is for lack of similarity to truth that we do not 
readily believe that which has nothing like that which we 
know. Thus when an ambassador told the king of Siam that 
with us the water was so hardened in winter that an elephant 
might walk thereon without breaking through, the king said 
to him : Hitherto I have believed you as a man of good faith ; 
now I see that you lie. § 6. But if the testimony of others can 
render a fact probable, the opinion of others should not pass 
of itself as a true ground of probability. For there is more 
error than knowledge among men, and if the belief of those 
whom we know and esteem is a legitimate ground of assent, 
men have reason to be Heathen in Japan, Mahometans in 
Turkey, Papists in Spain, Calvinists in Holland, and Luther- 
ans in Sweden. 

Th. The testimony of men is no doubt of more weight than 
their opinion, and in reason it is also the result of more 
reflection. /But you know that the judge sometimes makes 
them take the oath de crediditate, as it is called ; that in the 
examinations, we often ask witnesses not only what they have 
seen but also what they think, demanding of them at the 
same time the reasons of their judgment, and whether they 
have reflected thereupon to such an extent as behooves them. 
Judges also defer much to the views and opinions of ex- 
perts in each profession; private individuals, in proportion 
as it is inconvenient for them to present themselves at the 
appropriate examination, are not less compelled to do this. 
Thus a child, or other human being whose condition is but 
little better in this respect, is obliged, whenever he finds him- 
self in a certain situation, to follow the religion of the coun- 
try, so long as he sees nothing bad therein, and so long as he 
is not in a condition to find out whether there is a better. A 
tutor of pages, whatever his sect, will compel them each to 
go to the church where those who profess the same belief as 
this young man go. The discussions between Nicole 1 and 
others on the argument from the great number in a matter of 

1 Pierre Nicole, 1625-1695, one of the most distinguished of the Port-RoyaL- 
ists, and, with the exception of Arnauld (cf. ante, p. 463, note 4) and Pascal, the 
most accomplished member of the school, was author with Arnauld of the fa- 



xv] ON HUMAN UNDERSTANDING 531 



faith may be consulted, in which sometimes one defers to it 
too much and another does not consider it enough. -There are 
other similar prejudgments by which men would very easily 
exempt themselves from discussion. These are what Tertul- 
lian, in a special treatise, calls Prescrijotiones, 1 availing him- 
self of a term which the ancient jurisconsults (whose lan- 
guage was not unknown to him) intended for many kinds of 
exceptions or foreign and predisposing allegations, but which 
now means merely the temporal prescription when it is in- 
tended to repel the demand of another because not made with- 
in the time fixed by law. Thus there was reason for mak- 
ing known the legitimate prejudgments both on the side of the 
Soman Church and on that of the Protestants. It has been 
found that there are means of opposing novelty, for example, 
on the part of both in certain respects ; as, for example, when 
the Protestants for the most part abandoned the ancient form 
of ordination of clergymen, and the Romanists changed the 
ancient canon of the Old Testament books of Holy Scripture, 
as I have clearly enough shown in a discussion I had in 
writing, and from time to time, with the bishop of Meaux, 
whom we have just lost, according to the news which came 
some days since. 2 Thus these censures being mutual, the 
novelty, although it presents a suspicion of error in these 
matters, is not a certain proof thereof. 

mous L'Art de Penser or the Port Royal Logic. His most important work is 
his JSssais de Morale, Paris, 1671-74. It was about his De Vunite' de Ve'glise ou 
refutation du nouveau systeme de Jurien, Paris, 1687, that the theological 
controversies here alluded to by Leibnitz centred, and " in which the question 
was considered, whether Roman Catholicism allows itself to engage in the — 
undoubtedly questionable — argument of the ' majority of professors.'" An 
account of Nicole's Be Vunite de Ve'glise will be found in Bayle's Diet., Eng. 
transl., Vol. 4, p. 363, London, 1737. — Tr. 

1 Tertullian, 150-160 — 220-240, sought in his De Prsescriptione Hsereticorum 
to produce a formal general argument against all heresies — "adversus hsere- 
ses omnes " — his object being to prevent heretics, in accordance with certain 
just and necessary rules (prsescriptiones) , from appealing to Scripture in sup- 
port of their views. For an account of the work, cf. Smith and Wace, Diet. 
of Christ. Biog., Vol. 4, p. 837 a, sq. — Tr. 

2 Leibnitz here refers to his correspondence with Jacques Benigne Bossuet, 
1627-1704, Bishop of Meaux from 1681 till his death. This correspondence was 
irenic in character, and extended, with some interruptions, over a period of 
about 25 years, but was without result, because Leibnitz would not suffer the 
freedom of scientific inquiry to be taken away, while Bossuet desired sub- 
jection to the infallible authority of the church. The entire correspondence 
has been published by Foucher de Careil, QSt/vres de Leibniz, Vols. 1, 2, 



532 LEIBNITZ'S CRITIQUE OF LOCKE [bk. 



CHAPTER XVI 

OF THE DEGREES OF ASSENT 

§ 1. Ph. As for the degrees of assent, we must take care 
that the grounds of probability we have do not operate beyond 
the degree of likelihood found therein or which has been found 
therein when they are examined. For we must admit that 
assent cannot always be based upon an actual view of the rea- 
sons which have prevailed with the mind, and it would be 
very difficult even for those x Avho have an admirable memory 

Paris, 1859-60. A portion of the same is found in Dutens, Leibnit. op. om., 1, 
507 sq. The letters especially referred to are (1) of Leibnitz: Dec. 11, 1699, 
(Foucher de Careil, (Euvres de Leibniz, 2, 274-277 ; Dutens, Leibnit. op. om., 1, 
591-596), May 14 and 24, 1700 (F. 2, 314-369 ; D. 1, 612-642) ; (2) of Bossuet : Jan. 
9 and 30, 1700 (F. 2, 278-306; D. 1, 596-611), Aug. 17, 1701 (F. 2, 396-^26; D. 1, 
657-673). For an account of the controversy, cf. Pichler, Lie Theologie des 
Leibniz, Vol. 2, pp. 206-215. 

The present passage is important, as it enables us to determine the date of 
the composition of the New Essays, or at least of this portion of them. Bos- 
suet died April 12, 1704. This passage must then have been written in the 
second half of April, 1704; and from other data (for which cf. Guhrauer, 
Leibniz. Eine Biographie, Bk. II., p. 282 and Anmerkungen z. zweiten Buche, 
pp. 38-39 ; and Gerhardt's Introduction to the New Essays, ante, pp. 8, 9, and 
notes) it is evident that the entire work was substantially completed in 1704, 
though the revision of the French style, and possibly some minor additions or 
alterations, occupied Leibnitz to a certain extent after this date. 

In this connection it is to be noted that the date given, ante, p. 9, line 15, 
1709, should be 1704 {cf. Gerhardt, Leibniz, philos. Schrift., 3, 297, note *), and 
that Gerhardt's remark, ante, p. 9: "On the other hand, he remarks, well- 
nigh it seems in the opposite sense," etc., as well as that by the Translator, 
ante, p. 101, note \,prope.fin.: " As Leibnitz was occupied . . . with the com- 
position and revision of his New Essays, from 1700 ... to 1709 and perhaps 
later . . . possibly even as late as 1714 or 1716," should be modified accord- 
ingly.— Tr. 

1 Gerhardt's text reads: " Sur une veue actuelle des raisons, qui ont prevalu 
sur Vesprit, et il seroit tres difficile, meme a ceux, qui out une memoire ad- 
mirable," etc. The words italicised above are not found in the texts of Raspe, 
Erdmann, Jacques and Janet; and Janet restores the sense of "this incorrect 
phrase" thus: "... Sur une vue actuelle des raisons, comme il arrive chez 
ceux qui ont une memoire admirable, capable de toujours retenir. ..." 
Gerhardt's reading agrees with Locke's text, cf. Philos. Wks., Vol. 2, p. 271, 
Bohn's ed., and is therefore to be preferred. — Tr. 



ch. xvi] ON HUMAN UNDERSTANDING 533 

always to retain all the proofs which have compelled them to 
a certain assent, and which sometimes might fill a volume on a 
single question. - It suffices that they have once examined the 
matter minutely with sincerity and with care, and that they 
have, so to speak, cast up the account. § 2. Without this men 
must be very sceptical, or change their view at every moment, 
in order to yield themselves to every man who, having exam- 
ined the question of late, offers them arguments which they 
cannot at once wholly answer, for lack of memory or of appli- 
cation at leisure. § 3. It must be admitted that this often 
makes men obstinate in error : but the fault is, not that they 
rely upon their memory, but that they have badly judged be- 
fore. For often the remark that they have never thought 
otherwise takes the place of an examination and of reason 
with men. But ordinarily those who have least examined 
their opinions hold them most tenaciously. Holding to what 
one has seen is praiseworthy, but not always to what one has 
believed, because some consideration may have been left behind 
capable of overturning all. There is perhaps no one in the 
world who has the leisure, patience, and means of assembling 
all the proofs on both sides of the question upon which he 
has his opinions in order to compare these proofs and safely 
to conclude that nothing more remains for him to know for his 
more ample instruction. But the care of our life and of our 
more important interests cannot bear the delay, and it is abso- 
lutely necessary that our judgment be determined upon the 
points when we are incapable of attaining to a certain knowl- 
edge. 

Th. There is nothing but what is good and solid in what 
you, sir, have just said. It would be desirable, however, for 
men to have at certain junctures written abstracts (in form of 
memoranda) of the reasons which have led them to an impor- 
tant opinion, which they are obliged often to justify after- 
wards to themselves or others. Besides, although in a matter 
of justice it is not usually allowable to retract the judgments 
which have been passed, and to revise the verdicts agreed 
upon (otherwise there would necessarily be perpetual unrest, 
which would be so much the more intolerable as the accounts 
of things past cannot always be preserved), yet one is some- 
times allowed upon new light to sue for justice, and also to 



534 LEIBNITZ'S CKITIQUE OF LOCKE [bk. iv 

obtain what is called restitutio in integrum 1 contrary to the 
decision that has been given. And likewise in our own 
affairs, especially in matters very important, where it is still 
allowable to embark or to put back, and where it is not preju- 
dicial to suspend their execution and to proceed bridle in 
hand, the decisions of our minds based upon probabilities 
should never so pass in rem judicatam* as the jurisconsults call 
it, i.e. to a settlement, that we may not be disposed to the 
revision of the reasoning when new counter reasons of weight 
present themselves. But when there is no more time for delib- 
eration, we must follow the judgment we made with as much 
firmness as if it were infallible, but not always with so much 
strictness. 3 

§ 4. Ph. Since, then, men cannot avoid exposing themselves 
to error in judgment and having different opinions, since they 
cannot look at things from the same points of view, they must 
maintain peace between themselves and the duties of humanity 
amid this diversity of opinions without claiming that another 
should promptly change a rooted opinion upon our objec- 
tions, especially if there is room for supposing that his 
adversary acts from interest or ambition or from some other 
private motive. Most frequently those who would impose 
upon others the necessity of yielding to their opinions have 
examined things with but little thoroughness. For those who 
have entered beforehand sufficiently into the discussion to 
extricate themselves from doubt are so few in number, and 
find so little reason to condemn others, that nothing violent 
is to be expected on their part. 

Tli. Really that which one has the most right to censure in 
men is not their opinion, but their rash judgment in censuring 

1 Of. Paulus, Sententiarum, Lib. I., Tit. VII. 1. : "Integri restitutio est re- 
dintegrandse rei vel causae actio. 2. Integri restitutionem praetor tribuit ex 
bis causis, quae per metum, dolum et status permutationem, et justum errorem, 
et absentiam necessariani, et infirmitatem aetatis gesta esse die untur; " also 
Digest, Lib. XLIL, Tit. I. 33. 

2 Cf. Digest, Lib. XLIL, Tit. LI: " Res judicata dicitur, quae finem con- 
troversiam pronunciatione judicis accipit : quod vel condemnatione vel abso- 
lutione contingit." — Tr. 

3 Janet cites as a parallel passage Descartes, Discours de la Me'thode, Pt. 
III. : " Ma seconde maxime e'tait d'etre le plus ferine et le plus resolu en mes 
actions que je pourrais, et de ne suivre pas moiiis constamment les opinions 
les plus douteuses lorsque je m'y serais une fois determine que si elles eussent 
ete tres-assurees." — Te. 



ch. xvi] ON HUMAN UNDERSTANDING 535 

that of others, as if it were necessary to be stupid or wicked 
to judge differently from themselves; a condition of things 
which, in the authors of these passions and hatreds who spread 
them among the public, is the effect of a mind haughty and 
unfair, which loves to rule and cannot suffer contradiction. 
JSTot that there is not, in truth, reason very often for censuring 
the opinions of others, but it must be done in a spirit of fair- 
ness, and sympathy with human weakness. It is true that 
we are right in taking precautions against bad doctrines, 
which are influential upon manners and upon practical piety : 
but we must not attribute them to people to their prejudice 
without having good proofs of the same. If fairness wishes 
to spare persons, piety demands the representation, where it is 
fitting, of the bad effects of their dogmas when they are in- 
jurious, as those are which are contrary to the providence of a 
perfectly wise, good, and just God, and contrary to that 
immortality of souls which renders them susceptible of the 
effects of his justice, not to speak of other opinions dangerous 
as regards morality and the police. I know that excellent and 
well-meaning men maintain that these theoretic opinions 
have less influence upon practice than is thought, and I also 
know that there are persons of an excellent disposition whom 
these opinions will never make do anything unworthy of 
themselves : as also those who have reached these errors by 
speculation, are by nature wont to be farther removed from 
the vices to which men in general are susceptible, besides the 
fact that they are careful of the dignity of the sect in which 
they are, as it were, chiefs ; and it may be said that Epicurus 
and Spinoza, for example, have led a life wholly exemplary. 
But these reasons cease most frequently in their disciples or 
imitators, who, believing themselves released from the trouble- 
some fear of an overseeing Providence and of a menacing 
future, give loose reins to their brutish passions, and turn 
their mind to the seduction and corruption of others; and if 
they are ambitious and of a disposition somewhat harsh, they 
will be capable, for their pleasure or advancement, of setting 
on fire the four corners of the earth, as I have known from the 
character of some whom death has swept away. I find also 
that similar opinions insinuating themselves little by little 
into the minds of men of high life who rule others and upon 



536 LEIBNITZ'S CRITIQUE OF LOCKE [bk. IV 

whom affairs depend, and slipping into the books in fashion, 
dispose all things to the general revolution with which 
Europe is threatened, and accomplish the destruction of what 
still remains in the world of the generous sentiments of the 
ancient Greeks and Eomans, who preferred love of country 
and of the public good, and regard for posterity to fortune, 
and even to life. These public spirits, as the English call 
them, are fast diminishing, and are no longer in fashion; and 
they will diminish still faster when they are no longer sus- 
tained by the good morality and true religion which even 
natural reason teaches us. The best of the opposite character 
Avho are beginning to rule have no other principle than that they 
call honor. But the mark of the honest man and of the man of 
honor with them is only to do no baseness as they understand 
it. And if for the sake of power or through caprice anyone 
poured forth a deluge of blood, if he turned every sense upside 
down, that would be counted as nothing, and a Herostratus x of 
the ancients or a Don Juan in the " Festin de Pierre " 2 would 
pass for a hero. Boldly they scoff at the love of country, they 
ridicule those who care for the public, and when any well-mean- 
ing man speaks of what will become of posterity, they reply: 
we shall see when the time comes. But these persons will pos- 
sibly experience themselves the evils they think reserved for 
others. If, however, this disease of an epidemic mind whose bad 
effects begin to be visible is corrected, these evils will perhaps 
be prevented; but if it goes on increasing, Providence will 
correct men by the revolution itself which must spring there- 
from: for whatever may happen, everything will always turn 
out for the better in general at the end of the account, although 
that ought not and cannot happen without the punishment of 
those who have contributed even to the good by their bad acts. 
But I return from a digression into which the consideration of 
truthful opinions and of the right of censuring them has led me. 

1 Herostratus, an Ephesian, who, for the sake of making his name famous, 
as he himself confessed on heing put to torture, set fire to the temple of Ar- 
temis at Ephesus, on the night in which Alexander the Great was horn, 
356 B.C. — Tk. 

2 The Don Juan ou le Festin de Pieive, 1665, a comedy of Moliere, 1622- 
1673, the principal character of which is Don Juan. The play, written in 
prose, was versified in 1677, at the request of Moliere's widow, hy Thomas 
Corneille, 1625-1709.— Tk. 



ch. xvi] ON HUMAN UNDERSTANDING 537 

Now as in theology censures go very much, farther than else- 
where, and as those who lay great stress upon their orthodoxy, 
often condemn their adversaries, to whom those in the same 
party who are called syncretists by their adversaries are 
opposed, this opinion has caused civil wars to spring up 
between the rigid and condescending in one and the same 
party. But, as to refuse eternal salvation to those who are of 
another opinion is to encroach upon the rights of God, the 
wisest of those who condemn, only indicate the peril in which 
they think they see erring souls, and leave to the peculiar 
mercy of God those whose wickedness does not render them 
incapable of profiting therefrom, and on their part believe 
themselves obliged to make all imaginable efforts to withdraw 
them from a condition so dangerous. If these persons who 
thus judge of the perils of others have come to this opinion 
after a suitable examination and there are no means of dis- 
abusing them of it, their conduct cannot be censured so long 
as they use only fair means. But as soon as they go farther, 
they violate the laws of equity. For they should consider 
that others persuaded like themselves have an equal right to 
maintain their views, and even to spread them if they think 
them important. Opinions must be excepted which teach 
crimes that should not be allowed, and which it is right to 
suppress by stringent means, if it should be true, indeed, that 
he who maintains them cannot be rid of them; 1 as it is right 
to destroy even a poisonous animal, wholly innocent as it is. 
But I speak of suppressing the sect and not men, since we 
can prevent them from doing harm and dogmatising. 

§ 5. Ph. To return to the ground and degrees of assent, it 
is proper to remark that propositions are of two kinds. Some 
are of fact, and, depending upon observation, may be based upon 
human testimony ; others are speculative, and, regarding things 
which our senses could not discover, are incapable of similar 
testimony. § 6. When a particular fact is in conformity with 
our constant observations, and with the uniform report of 
others, we rest upon it as firmly as if it were certain knowl- 

1 Gerhardt reads: "ne peut point s'en defaire." Erdmann, Jacques and 
Janet read: "ne peut point s'en faire," and Janet in his note says : "supply 
' d'autres.' " With this reading the meaning is: " cannot procure for himself 
others." — Tr. 



538 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

edge, and where it is in conformity with the testimony of all 
men, in all ages, so far as can be known, it is the first and 
highest degree of probability; for example, that fire warms, 
that iron sinks to the bottom of the water. Our belief built 
upon such foundations rises to assurance. § 7. In the second 
place, all historians relate that such an one has preferred his 
individual interest to that of the public, and as it has always 
been observed that this is the custom of the majority of men, 
the assent I give to these histories is confidence. § 8. Thirdly, 
when there is nothing either for or against it in the nature of 
things, a fact, vouched for by the testimony of unsuspected 
people, for example, that Julius Ceesar lived, is received with 
a, firm belief. § 9. But when the testimony is found contrary 
to the ordinary course of nature or the witnesses vary among 
themselves, the degrees of probability may vary infinitely, 
whence arise these degrees which we call belief, conjecture, 
doubt, uncertainty, distrust; and there it is that exactness is 
necessary to form a right judgment and to proportion our 
assent to the degrees of probability. 

Th. Jurisconsults in treating of proofs, presumptions, con- 
jectures, and indices, have said a number of good things on 
this subject, and have gone into some considerable detail. 
They begin with notoriety, in which there is no need of proof. 
Afterwards they come to complete proofs, or those which pass 
as such, upon which they pronounce sentence, at least, in a 
civil process, but upon which in some places they are more 
reserved in a criminal process; and they are not wrong in 
demanding in such case proofs more than complete, and espe- 
cially as regards what is called corpus delicti, according to the 
nature of the act. There are then proofs more than complete, 
and there are also ordinary complete proofs. Then there are 
presumptions, which pass provisionally as complete proofs, 
i.e. so long as the contrary is not proved. There are proofs 
more than half complete (to speak precisely), in which the one 
who relies upon them is allowed to swear to make them good 
(the juramentum suppletorium) ; there are others less than half 
complete, where wholly to the contrary the oath is adminis- 
tered to him who denies the act, to purge himself (the jura- 
mentum purgationis) . Beyond this there are many degrees 
of conjectures and indices. Particularly in a criminal process 



ch. xvi] ON HUMAN UNDERSTANDING 539 

there are indices (ad torturam) to proceed to the torture, which 
itself has its degrees indicated by the formulas of arrest; 
there are indices (ad terrendum) sufficient to show the instru- 
ments of torture and to prepare things as if they intended to 
come to it. There are some (ad capturam) to make sure of 
a suspected man; and (ad inquirendum) to make inquiries 
secretly and without noise. And these differences may be of 
use also on other similar occasions. The entire form of judi- 
cial procedure is nothing else in fact than a species of logic 
applied to questions of law. Physicians also have a number 
of degrees and differences in their signs and indications which 
may be seen among them. The mathematicians of our times 
have begun to calculate chances upon the occasion of games. 
Chevalier de Mere, 1 whose "Agremens" and other works have 
been printed, a man of penetrating mind who was both a 
player and a philosopher, gave them an opportunity by form- 
ing questions regarding the profits in order to know how much 
the game would be worth, if interrupted at such or such a 
stage. In this way he induced Pascal, his friend, to examine 
these things a little. The question made a stir and gave 
Huygens the opportunity to produce his treatise "de Alea." 2 

1 Cf. ante, p. 213, note 2 ; also Response {Replique) aux inflexions contenues 
dans la seconde Edition du Dictionnaire Critique de M. Bayle, Gerhardt, 4, 
570, Erdinami, 190, Janet, 2, 593, Dutens, 2, Pt. I., 92. Antoine Gombault, 
chevalier de Mere, c. 1610-1684, was erroneously confounded with a Georges 
Brossin, chevalier de Mere, belonging to another family, by all biographers 
since Moreri, until the special researches of M. de Bremont d'Ars proved the 
error and assigned him his right name. He had an inordinately exalted idea 
of his own importance and attainments, especially in mathematics. His 
Agrements, discours de M. le chevalier de Mere a M me **, appeared in 1677, 
12mo, and in the collected edition of all his works, entitled (JEuvres du chevalier 
de Mere, Amsterdam, 1692, 2 vols., 12mo. A volume of (JEuvres posthumes, 
12mo, appeared at Paris, 1700, and again at The Hague, 1701. For further 
account of him, cf. Larousse, Grande Diet. Univ. de XIX me Siecle, Vol. 11, p. 
72.— Tk. 

2 Cf. ante, p. 150> note 3. Huygens' De ratiociniis in alese ludo, dated The 
Hague, 1657, is found in F. van Schooten, Exercitat. math. lib. V., pp. 514-539, 
Lugd. Bat. 1657, 4to. It was written by Huygens in Dutch and translated into 
Latin by Schooten. There are two English translations, one attributed to 
Motte, but probably by Arbuthnot ; the other by W. Brown. Cf. I. Todhunter, 
Hist, of the Math. Theory of Probability , pp. 22-23, Cambridge and London, 
Macmillan & Co., 1865. Leibnitz, Miscellan. Leibnit., No. CXIIL, cf. Dutens, 
6, Pt. I., 318, says of it: " Christiani Hugenii ratiocinia de lusu alese, Franc. 
Schotenii scriptis mathematicis adjecta, sunt elegans specimen ratiocinationis 
de gradibus probabilitatis." 

Spinoza also discussed the calculation of probabilities in games of chance, 



540 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

Otlier learned men entered into the subject. Some principles 
were established of which the Pensioner De Witt also availed 
himself in a brief discourse printed in Dutch on annuities. 1 
The foundation on which they have built goes back to the 
prosthaplioiresis,- i.e. the taking of an arithmetical mean be- 
tween several equally receivable suppositions.-^ Our peasants 
also have made use of it for a long time according to their 
natural mathematics. For example, when some inheritance or 
land is to be sold, they form three bodies of appraisers ; these 
bodies are called Schurzen in Low Saxon, and each body makes 
an estimate of the property in question. Suppose, then, that 
the first estimates its value to be 1000 crowns, the second 
1400, the third 1500; the sum of these three estimates is 
taken, viz. 3900, and because there were three bodies, the 
third, i.e. 1300, is taken as the mean value asked for; or 
rather, they take the sum of the third part of each estimate 
which is the same thing. This is the axiom: wqualibns 
cequalia, equal suppositions must have equal consideration. 
But when the suppositions are unequal they compare them 
with each other. Suppose, for example, that with two 
dice, the one ought to win if it makes 7 points, the 
other if it makes 9, the question is asked what proportion 
obtains between their probabilities of winning? I reply that 
the probability of the last is worth only two-thirds of the 

in a letter to Jan van der Meer. Cf. Epistola No. 38 (formerly 43) , Spinoza, 
Opera, ed. Van Vloten and Land, 2, 145-149 (in Latin and Dutch) ; Spinoza's 
Brief wechsel, in J. H. v. Kirchmann's Philos. Bibliothek, Vol. 46, pp. 145- 
147. — Tb. 

1 Cf. ante, p. 426, note 2. John De Witt appears to have been " the first to 
apply scientific principles to the calculations connected with annuities, which 
are analogous to those connected with assurances." His report on this sub- 
ject was presented to the States General, July 30, 1671. It was entitled De 
vardye van de lif-renten na proportie van de los-renten, and appeared at La 
Haye, 1671. An abstract of it, showing exactly how De Witt reasoned on the 
subject, will be found in M. Nicolas Struyck, Inleiding tot het algemeine geo- 
graphy, etc., p. 345, Amsterdam, 1740, 4to, and an English translation of the 
tract is printed in Contributions to the Hist, of Insurance by Frederick 
Hendriks in the "Assurance Magazine," Vol. 2 (1852), p. 231. For some 
remarks on De Witt's hypothesis as to the rate of mortality, cf. the same vol., 
p. 393. — Tr. 

2 Prosthaphseresis — npoaBa^aipEa-^ — = a previous subtraction. The term 
here signifies " the fundamental principle for the ascertainment of the degree 
of probability which requires us to take the arithmetical mean of the existing 
suppositions estimated according to their relative value." —Tr. 



ch. xvi] ON HUMAN UNDERSTANDING 541 

probability of the first, for the first can make 7 in three ways 
with two dice, viz. : by 1 and 6, or 2 and 5, or 3 and 4; and 
the other can make 9 in two ways only, by throwing 3 and 6, 
or 4 and 5; and all these methods are equally possible. 
Then the probabilities, which are as the numbers of equal 
possibilities, will be as 3 to 2, or as 1 to f . I have more than 
once said that a new kind of logic would be required which 
would treat of the degrees of probability, since Aristotle in 
his " Topics " has done nothing less than this, and has con- 
tented himself with putting in a certain order certain popular 
rules distributed according to the common topics, which may 
be of use on some occasion where the question concerns the 
amplification of the discourse and the giving to it probability 
without putting it to the trouble of furnishing us a necessary 
balance for weighing probabilities and forming thereupon a 
solid judgment. 1 It would be well for him who should treat 
of this matter to pursue the examination of games of chance; 
and in general I wish that some skilful mathematician would 
produce an ample work with full details and thoroughly 
reasoned upon all sorts of games, which would be very useful 
in perfecting the art of invention, the human mind appearing 
to better advantage in games than in the most serious matters. 
_ § 10. Ph. The law of England observes this rule, that the 
copy of an act received as authentic by witnesses is a good 
proof, but the copy of a copy, however attested, and by wit- 
nesses the most credible, is never admitted as a proof in a 
trial. I have never yet heard any one censure this wise pre- 
caution. This observation at least may be drawn from it, 
that testimony has less force in proportion as it is farther 
removed from the original truth which is in the thing itself; 
while among certain peoples use is made of it in a directly 
contrary manner, opinions acquiring force as they grow older, 
and what would not at all have appeared probable a thousand 
years ago to a reasonable man a contemporary of the one who 
first certified it, passes at present as certain because many 
have related it upon his testimony. 

Th. Historical critics have great regard for contemporary 
witnesses of things : but a contemporary even merits belief 
chiefly as regards public events only ; but when he speaks of 

1 Of. ante, p. 417, note 3.— Tr. 



542 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

motives, secrets, hidden forces, and things which may be dis- 
puted, as, for example, poisonings, assassinations, we acquaint 
ourselves with what many have believed. Procopius is very 
credible when he speaks of the war of Belisarius against the 
Vandals and the Goths, but when he retails horrible scandals 
against the Empress Theodora in his "Anecdotes," he may 
believe them who will. 1 ^Generally, we should be very re- 
served in believing satires ; we see some published in our times 
which, although wholly improbable, have nevertheless been 
greedily swallowed by the ignorant. And some day perhaps 
it will be said : Is it possible that one would have dared to 
publish these things at that time, if there had been any appar- 
ent foundation for them ? But if this statement is some day 
made, the judgment will be a very erroneous one. The world, 
however, is inclined to indulge in satire ; and, to quote but 
one example, the late Mr. Maurier, the son, 2 having published, 
from some caprice, in his memoirs printed some years since, 
certain things wholly without foundation against the incom- 
parable Hugo Grotius, ambassador from Sweden to France, 
stirred apparently by some unknown circumstance against the 
memory of this illustrious friend of his father, I have noticed 
that many authors have repeated them from envy, although 
the negotiations and letters of this great man sufficiently 
make known the contrary. We have emancipated ourselves 
indeed from writing romances in history, and he who produced 
the last life of Cromwell thought that in order to enliven the 
subject he was allowed, in speaking of the life, still private, 
of this clever usurper, to make him travel in France, where 
he follows him into the public houses of Paris as if he had 

1 For critical discussion of the authorship of the TA ' XvixSoja — Anecdota 
or Historia Arcana — of Procopius, and of the credibility of its. contents, cf. 
J. H. Reinkens, Anecdota sintne scripta a Procopio Csesariensi inquiritur, 
Breslau, 1858, who denies, and F. Dahn, Prokopius von Ciisarea, Berlin, 1865, 
who affirms, that Procopius is the author. Prof. James Bryce gives a brief 
account and estimate of the work in his article on "Procopius," in the 
Encyclop. Brit. 9th ed. Cf. also M. Debidour, Thesis, 1877, who tries to make 
out the best case he can for Theodora, and Prof. Bryce in the " Contemporary 
Review," Feb. 1885. — Tr. 

2 Louis Aubery du Maurier, the historian, died 1687, was the son of 
Benjamin Aubery, an ambassador from France to Holland, and published 
Memoires pour servir a VHistoire de Hollande, 1680, Memoires de Hamburg, 
de Lubeck, de Holstein, etc. Leibnitz refers to him in his letter to Bierling, 
Oct. 24, 1709, Gerhardt, 7, 487.— Tr. 



ch. xvi] ON HUMAN UNDERSTANDING 543 

been his master. 1 But it appears by the history of Cromwell 
written by Carrington, a well-informed man, and dedicated 
to his son Richard when he acted the part of the Pro- 
tector, that Cromwell never went out of the British Isles. 
Detail especially is uncertain. There are almost no good 
accounts of battles ; the majority of those of Titus Livius 
appear to be imaginary, as well as those of Quintus Curtius. 
It would be necessary to have on both sides the accounts of 
exact and capable men, who indeed would draw up plans of 
them like those which the Count of Dahlberg, who had already 
served with distinction under the King of Sweden, Charles 
Gustavus, and who, being Governor-General of Livonia, re- 
cently defended Biga, has had engraved touching the actions 
and battles of this prince. We must not, however, at once 
decry a good historian at a word from some prince or minister 
who has exclaimed against him on some occasion, or in regard 
to some subject not to his taste or wherein there really is per- 
haps some fault. The story is told that Charles the Fifth, 
wishing to have something of Sleidan 2 read, said: "Bring me 
my story-teller (menteur) ," and that Carlowitz, a Saxon gentle- 
man, of good repute at that time, said that the history of Slei- 
dan destroyed in his mind all the good opinion he had had of 
the ancient histories. That statement, I say, will have no force 
in the minds of well-informed persons in overthrowing the 
authority of the history of Sleidan, the best part of which is 
a series of the public acts of the Diets and Assemblies, and 
of the writings authorized by the princes. ~ And if there re- 
mained the least scruple regarding it, it has just been removed 
by the excellent history of my distinguished friend, the late 
Mr. Von Seckendorf 3 (in which I cannot, however, refrain 

1 Leibnitz here refers, according to Schaarschniidt, to Jas. Heath's Flagel- 
lum; or the Life and Death, Birth and Burial of Oliver, the late Usurper, 
London, 1663, 8vo. In this book the Protector is generously slandered and 
abused. S. Carrington's The Hist, of the Life and Death of Oliver Cromwell, 
London, 1659, 8vo, is a panegyric, in which Cromwell is compared, among 
others, with Alexander the Great. An abridgment of Heath's book may be 
found in the " Harleian Miscellany," 1, 279, ed. Park. It may be added that 
" the earliest lives of Cromwell were either brief chronicles of the chief events 
of his life or were panegyrics." — Tr. 

2 Cf. ante, p. 114, note 1. — Tr. 

3 Veit Ludwig von Seckendorf, 1626-1692, a distinguished German scholar 
and statesman, whose Commentarins historicus et apologeticus de Lutheran- 



544 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

from disapproving the term " Lutlieranism " on the title-page, 
which a bad custom has authorized in Saxony), wherein the 
majority of the statements are justified by extracts from an 
immense number of pieces, drawn from the Saxon archives 
which he had at his disposal, although the Bishop of Meaux, 
who contested their validity, and to whom I sent it, merely 
replied to me that this book is horribly prolix ; but I could 
wish that it were twice as large on the same scale. ^The more 
ample it is, the more hold it must give, since one has only to 
choose his passages ; besides, there are some esteemed histori- 
cal works which are much greater. For the rest, we do not 
always despise authors x^osterior to times of which they 
speak when what they relate is apparently otherwise. Some- 
times, also, it happens that they preserve some most ancient 
pieces. For example, there has been doubt as to what family 
Suibert, Bishop of Bamberg, since Pope under the name of 
Clement II., belonged. An anonymous author of the history 
of Brunswick, who lived in the fourteenth century, named his 
family, and some persons learned in our history desired to pay 
no regard whatever to it ; but I have had a chronicle much 
more ancient, not yet printed, in which the same statement is 
made with more details, from which it appears that he be- 
longed to the family of the ancient allodial seigniors of Horn- 
bourg (not far from Wolfenbuttel), the territory of which was 
given by the last owner to the cathedral church of Halber- 
stadt. 

§ 11. Ph. I do not wish you to think that I desired to lessen 
the authority and use of history by my remark. It is from 
this source that we receive with a convincing evidence a large 

ismo sive de Reformatione, Leipzig, 1692, 3 vols., fol., occasioned by and 
directed against the L'Histoire clu Luther anisme, Paris, 1680, of the Jesuit 
Maimbourg, is his most important work, and a rich storehouse of authentic 
materials for the history of the reformation from 1517-1547, drawn from 
documents contained in the Saxon archives, the writings of the reformers and 
their contemporaries, accompanied by a polemical and historical commentary. 
It is the work of an able, philosophic mind, with scarcely a trace of the secta- 
rian spirit. Leibnitz gives a brief account and estimate of the book in his 
letters to Bossuet, Jan. 8-18, and April 8-18, 1692 (c/. Foucher de Careil, 
CEuvres de Leibniz, 1, 228, 275, Dutens, Leibnit. op. om., 1. 523-4, 530-531). It 
is also referred to in Bossuet's letters to Leibnitz, Jan. 10, 1692 (F. 1, 226, D. 1, 
522), March 26 or May 26, 1692 (F. 1, 253), and Leibnitz to Bossuet, without 
dates (F. 1, 223, 254-255). For further remarks of Leibnhz concerning it, cf. 
Dutens, 5, 90, 93, 566. — Tr. 



en. xvi] ON HUMAN UNDERSTANDING 545 

part of our useful truths. I see nothing more valuable than 
the records of antiquity remaining to us, and I wish we had 
more of them, and less corrupted. But it is always true that 
no copy raises itself higher than the certainty of its first 
original. 

Tli. It is certain, that when we have a single ancient author 
as the authority for a fact, all those who have copied him add 
no weight thereto, or rather should be reckoned as nothing. It 
should be wholly as if what they said belonged to the number, 
twv anal; Aeyo/xeVwv, of things which have been said only once, 
a collection of which Menage * wished to make. - Moreover, to- 
day, if a hundred thousand petty writers should repeat the 
slanders of Bolsec 2 (for example), a man of judgment would 
value it no more than the noise of goslings. Jurisconsults 
have written de fide historica; but the subject merits a more 
exact research, and some of these gentlemen have been too 
indulgent. As for that which is of great antiquity, some of 
the most noted facts are doubtful. Clever people have doubted, 
with reason, whether Bomulus was the first founder of the 
city of Borne. There is dispute about the death of Cyrus, and 
besides, the discrepancy between Herodotus and Ctesias has 
spread doubt upon the history of the Assyrians, Babylonians, 
and Persians. That of Nebuchadnezzar, of Judith, and even 
of the Ahasuerus of Esther suffer from great difficulties. The 
Romans, when speaking of the gold of Toulouse, contradict 
the story of the defeat of the Gauls by Camillus. Above all, 
the particular and private history of peoples is without credit, 
unless it is taken from very ancient originals, and is suf- 
ficiently in conformity with public history. This is why the 

1 Cf. ante, p. 350, note 1.— Tr. 

2 Jerome Hermes Bolsec, bom at Paris, died "1685, at Lyons, was a Carmel- 
ite of Paris, who forsook his order, became a Protestant, fled to Italy and 
thence to Geneva, where he set up as a physician, but not meeting with the 
success he desired, gave himself up to theology, discoursed publicly on the 
doctrine of Predestination, advocating the views of Pelagius, and thus incur- 
ring the censure of Calvin, was imprisoned and then banished by the Senate of 
Geneva, Dec. 29, 1551. He went thence to Bern, whither Calvin pursued him. 
These persecutions developed in him a violent hatred towards Calvin, which, 
after his return to the Catholic faith, he vented in his L'Histoire de la vie, 
mozurs, actes, doctrine et mort de Jean Calvin, Paris, 1577, 8vo. He also pub- 
lished a similar work, L'Histoire de la vie, mozvrs, doctrine et de'porteme?its de 
Theodore de Beze, Paris, 1580, 8vo. Both works are merely pamphlets, with 
no historical authority. — Tr. 

2 N 



546 LEIBNITZ'S CRITIQUE OF LOCKE [bk iv 

stories told us of the ancient German, Gallic, British, Scotch, 
Polish, and other kings pass with reason as fabulous and 
made up.~ Trebeta, son of Mnus, founder of Treves, Bru- 
tus, ancestor of the Britons, or Britains, are as real as the 
Amadis. The tales taken from certain story-tellers, which 
Trithemius, 1 Aventin, 2 and even Albinus 3 and Sifrid Petri 4 
have taken the liberty to tell of the ancient princes of the 
Pranks, Boii, Saxons, Frisians ; and what Saxo Gramaticus 
and the Edda tell us of the remote antiquities of the north, 
cannot have more authority than what Kadlubko, 5 the first 
Polish historian, says of one of their kings, a son-in-law of 
Julius Caesar. But when the histories of different peoples 
agree in instances where there is no appearance that one has 
copied another, it is a great sign of their truth. Such is the 

1 Johann Trithemius, 1462-1516, abbot of Spanheim, whose Compendium, 
sive breviarium primi voluminis annalium, sive historiarum, de origine rerum 
et gentis Francorum appeared at Mainz, 1515, reprinted, Paris, 1539. Leib- 
nitz speaks of him in his Introd. in collectionem Scriptorum Histor. Bruns- 
vicensi inservientium, Dutens, 4, Pt. II., 4, 5. For an account of him, cf. 
Michaud, Biog. Univ. Vol. 46, pp. 551-559. —Tr. 

2 Johann Thurmayr Aventinus, 1466-1534, author of Annates Boiorum. 
His history, the materials of which were drawn from authentic sources, was 
finished in 1528, and published " with some important omissions " of passages 
adverse to the Roman Catholics by Zeigler in 1554. The omitted passages were 
afterwards restored by Nicolas Cisner in the Basle ed., 1580. Leibnitz mentions 
him in his Introd. in col. Script. Histor. Brunsvic, Dutens, 4, Pt. II., 4. — Tr. 

8 Alcuin, — Latin, Alcuinus or Albinus Flaccus, — c. 735-804, the instructor 
of Charlemagne, whose collected works, containing among other things some 
historical treatises, were first published by And. Duchesne, Paris, 1617, 1 vol., 
fob, and afterwards by Froben, Alcuini opera, post editionem ah And.Querce- 
tano curatam, de novo collata, emendata, aucta et illuslrata, 2 vols., fob, 
Ratisbon, 1777. Migne, Patrol., Vols. 100, 101, is a reprint of this ed. — Tr. 

4 Sifrid or Suffrid Petri, 1527-1597, a Dutch philologist of great learning, 
but deficient in critical ability and taste, was Professor of Latin and Greek in 
the University of Erfurt, 1557, of Law at Cologne, 1577, and of Canon Law at 
Louvain and Cologne,1585. He was the historiographer of the States of Fries- 
land, and published De Frisiorum antiquitate et origine lib. III., Cologne, 
1590; De Scriptoribics Frisise decades XVI. et semis, Cologne, 1593. His 
Historia veterum episcoporum Ultrajectinse sedis et comitum Hollandise, 
appeared at Francker, 1612. — Tr. 

5 Vincent Kadlubek or Kodlubko, 1161-1223, bishop of Cracow, a Latin 
chronicler of the early history of Poland, whose Historia Polonica, Do- 
bromiel, 1612, 12mo, written with spirit, but in a barbarous style, throws 
much light on the events of his own time, but must be received with caution, 
as regards the early period, since he treated the early legendary stories, many 
of which closely resemble the Scandinavian sagas, as genuine history. The 
work is in four books and extends to the year 1202, and is true and faithful 
in relating events in Poland in the 11th and 12th centuries. — Tr. 



ch. xvi] ON HUMAN UNDERSTANDING 547 

accord of Herodotus with the history of the Old Testament in 
many things, for example, when he speaks 1 of the battle of 
Megiddo between the king of Egypt, and the Syrians of Pales- 
tine, i.e. the Jews, in which, according to the testimony of 
the sacred history we have of the Hebrews, King Josias was 
mortally wounded. ^The consent of the Arabic, Persian, and 
Turkish historians with the Greeks, Bomans, and other occi- 
dentals gives pleasure to those who seek for facts ; as also 
the testimony which the medals and superscriptions, remain- 
ing from antiquity, render to the books which have come down 
from the ancients to us and which are, in reality, copies of 
copies. We must wait for what we shall yet learn of the 
history of China, until we are in a better condition to judge 
of it, and until it shall bear its credibility with itself. The 
use of history consists principally in the pleasure there is in 
knowing origins, in the justice rendered to the men who have 
deserved well of other men, in the establishment of historical 
criticism, and especially of sacred history, which supports the 
foundations of revelation, and (putting also aside the geneal- 
ogies and laws of princes and powers) in the useful teachings 
which the examples furnish us. I do not despise the thorough 
examination of antiquities, even to the smallest trifles ; for 
sometimes the knowledge which the critics draw from them 
may be of use in more important matters. I consent, for ex- 
ample, to the writing even of the entire history of clothing 
and of the tailor's art, from the garments of the Hebrew priests, 
or, if you please, from the peltries which God gave to the first 
bride and bridegroom at their departure from Paradise, to the 
top-knots and furbelows of our time, and to the union there- 
with of all that can be drawn from ancient sculptures and 
from paintings also made some centuries after. I will furnish 
indeed, if any one desires it, the memoirs of a man of Augs- 
burg of the past century, who is described with all the clothes 
which he wore from his infancy up to the age of 63 years. I 
do not know who told me that the late Duke of Aumont, 2 a 

1 Of. Herodotus II. 159, and notes of Bahr and Rawlinson on the passage. 
— Tr. 

2 Louis-Marie-Victor d' Aumont, 1632-1704, a French scholar, numismatist, 
and " brigadier du roi" under Louis XIV. in the Low Countries, contributed 
much to the progress of the knowledge of medals, and was a member of the 
" Academic des inscriptions et Belles-Lettres." — Tr. 



548 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

great connoisseur of fine antiquities, had a similar curiosity. 
^This may perhaps be of use in distinguishing the legitimate 
monuments from those which are not so, not to speak of other 
uses. And since men are allowed to play, they will still 
further be allowed to divert themselves with these kinds of 
work, if their essential duties do not suffer thereby. But I 
wish there might be some persons who would devote them- 
selves preferably to drawing from history that which is more 
useful, as the extraordinary examples of virtue, remarks upon 
the conveniences of life, stratagems of politics and of war. 
And I wish that a kind of universal history were written 
which should indicate only such things, and some few others 
of more consequence ; for sometimes one reads an extensive 
historical work, learned, well-written, suited also to the end 
of the author, and excellent of its kind, but which contains 
little useful instruction, by which I do not mean here simple 
morality, with which the " Theatrum vitae hunianae " 1 and other 
such florileges are filled, but skill and knowledge of which 
everybody would not think in case of need. I wish also that 
an infinite number of things of this nature, by which we might 
profit, might be drawn from books of travel, and be arranged 
according to the order of the subjects. But it is astonishing 
that while so many useful things remain to be done, men 
amuse themselves almost always with what is already done, 
or with purely useless things, or at least with what is the 
least important, and I see little remedy therefor until the 
public is more concerned about them in more tranquil times. 

§ 12. Ph. Your digressions give pleasure and profit. But 
from the probabilities of facts, let us come to those of opinions 
concerning things which do not fall under the senses. Such 
things are incapable of any testimony, for example, the exist- 
ence and 2 nature of spirits, angels, demons, etc., the material 
substances which are in the planets and other mansions 3 of 

1 Theodore Zwinger, 1533-1588, a celebrated Swiss physician, whose Thea- 
trum vitx humanse, " a vast compilation of historical facts and anecdotes, and 
of curious and piquant observations," in preparing which he availed himself 
of the materials wbich his father-in-law, Lycosthenes [Conrad Wolff hart] , 
1518-1561, had collected and asked him to set in order, appeared at Basle, 
1565-1601, 5 vols., fol. — Tb. 

2 Gerhardt reads : " de," a Ms. or typographical error ; Erdmann, Jacques, 
and Janet have " et." — Tr. 

3 Locke's word, Philos. Works, Vol. 2, p. 279 (Bonn's ed.). — Tb. 



ch. xvi] ON HUMAN UNDERSTANDING 549 

this vast universe ; finally, upon the mode of operation of the 
majority of the works of nature, and of all these things we 
can have merely conjectures, wherein analogy 1 is the great 
rule of probability. ^Tor being incapable of attestation, they 
can appear probable only so far as they agree more or less 
with established truths. As violent friction of two bodies 
produces heat and even fire, as the refractions of transparent 
bodies produce the appearance of colors, we think that fire 
consists in a violent agitation of the imperceptible parts, and 
that colors also, whose origin we do not see, come from a simi- 
lar refraction ; and finding that there is a gradual co?mection 
in all the parts of the creation that may be subject to human 
observation, without any considerable gap between any two, 
we have every reason to think that things rise also towards 
perfection gradually and by insensible degrees. 2 -It is difficult 
to say where the sensible and the rational begin, and what is 
the lowest degree of living things ; it is like the increase or 
diminution of quantity in a regular cone. The difference is 
exceeding great between certain men and certain animals; 
but if we wish to compare the understanding and capacity of 
certain men and certain brutes, we shall find so little differ- 
ence, that it will be very difficult to assert that the under- 
standing of these men is clearer or more extended than that 
of these brutes. When, therefore, we observe such an insensi- 
ble gradation between the parts of creation from man to the 
lowest parts beneath him, the rule of analogy makes us regard 
it as probable that there is a parallel gradation in the things 
above us and beyond the sphere of our observation, and this kind 
of probability is the broad foundation of rational hypotheses. 3 

1 In the case of natural phenomena beyond the reach of the senses, analogy 
is the great rule of probability, the reasoning in general being hypothetical 
only, and the force and certainty of the conclusion therefrom being directly 
proportional to the reality and degree of the resemblance or similarity of the 
phenomena. Since Locke's and Leibnitz's day, great advance has been made 
in our knowledge of the nature of the materials existing in the various heav- 
enly bodies, chiefly through the aid of the spectroscope and spectral analysis, 
not only strengthening and increasing the measure of probability in the appli- 
cation of the conclusion from analogy to the conjectured conditions of other 
worlds, but in some cases and to a certain extent giving us well accredited 
positive knowledge in regard to their constitution. — Tr. 

2 Cf. A. C. Fraser, Locke's Essay Concerning Human Understanding, Vol. 
2, p. 380, note 2. Oxford, Clarendon Press, 1894. — Tr. 

3 The probable conclusion from analogy is a rational hypothesis, 



550 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

Th. It is upon the ground of this analogy that Huygens, in 
his " Cosmotheoros," x judges that the condition of the other 
principal planets is quite similar to ours, excepting the differ- 
ence which their different distance from the sun must cause : 
and Fontenelle, 2 who had already before published his conver- 
sations full of wit and knowledge on the plurality of worlds, 

hypothetical character consists in the fact that it is not a completely exhaus- 
tive induction or a mathematical demonstration from the given data, therefore 
still problematical, and whose rationality consists in the fact that no known 
reason exists against the assumed instance, hut on the contrary the analogy 
itself directly furnishes occasion for a provisional consideration of, if not a 
belief in, the hypothesis. — Tr. 

1 Cf. ante, p. 150, note 3. Huygen's Cosmotheoros, sive de terris calestibus 
earumque ornatu conjecturse — a speculation concerning the inhabitants of 
the planets, and the last work of the great physicist and mathematician — 
appeared posthumously, at the Hague, 1698, and in a German trans., Leipzig, 
1703, just before Leibnitz wrote Bk. IV. of the Neiu Essays, and in an English 
trans., entitled, The Celestial WoiM discovered; or Conjectures concerning 
the Inhabitants, Plants, and Productions of the Worlds in the Planets, Lon- 
don, 1699, Svo ; Conjectures concerning the Planetary Worlds, Glasgow, 1727, 
12mo. The work is found in Huygens, Opera Omnia, Leyden, 1824, 2 vols., 
Vol. 1, pp. 641-722. — Tr. 

2 Bernard le Bovier de Fontenelle, 1657-1757, a litterateur rather than a 
philosopher, who, nevertheless, according to Janet, " belongs to the history of 
philosophy, through the spirit of inquiry and criticism which animates his 
works," attempted, and successfully, in his Entretiens sur la pluralite des 
mondes, Paris, 1686, 12mo (a sixth Entretien was added in the Paris ed. of 
1687, according to Brunet) to popularize the astronomical theories and doc- 
trines of Copernicus and Descartes. The work is a fine illustration of the 
possibility of making science, without ceasing to be scientific, intelligible and 
interesting to the men of the world. Fontenelle became a member of the 
" Academie Francaise " in 1691, and, on the revival of the "Academie des Sci- 
ences de Paris " in 1699, was nominated its perpetual secretary, and continued 
in that office for fifty-eight years, publishing each year a volume of the Ilistoire 
of this Academie, containing clear and orderly arranged extracts from or anal- 
yses of the papers read before the Academie, often accompanied with new and 
profound views of his own, together with Eloges of the members dying in 
each year, among which is the Eloge de Leibniz, "a masterpiece," found in 
U Ilistoire de V Academie Roy ale des Sciences de Paris, annee 1716; in Vol. 3, 
1722, of the collection of these Eloges, 69 in number, entitled Histoire du 
renouvellement de V Academie Roy ale des Sciences en 1699, et Eloges histonques 
des Acade'miciens morts depuis ce temps-la, 3 vols., Paris, 1708-1722; in 
CEuvres de Fontenelle, 3 vols., La Haye, 1728-29, Vol. 3, pp. 232-259; new ed., 
11 vols., Paris, 1766, Vol. 5, pp. 447-506; and in F. Bouillier, Eloges de Fon- 
tenelle avec une Introd. et des Notes, Paris, 1883, pp. 103-134; cf. also Jacques, 
CEuvres de Leibniz, Vol. 2, pp. i-xxiv, Dutens, Leibnit. op. om., Vol. 1, pp. 
xix-liii. 

The Entretiens sur la plurality des mondzs is found in CEuvres de Fon- 
tenelle, La Haye, 1728-1729, Vol. 1, pp. 149-234; new ed., Paris, 1766, Vol. 2, 
pp. 1-190; there is a German trans, by Gottsched, 1751, Eng. trans, by Glan- 
vill, London, 1688, 1768, by A. Behn and others, London, 1801, and from the 



for. xvi] ON HUMAN UNDERSTANDING 551 

has said some pretty things thereupon, and has discovered the 
art of enlivening a difficult 1 subject. -He would say, as it 
were, that a harlequin in the empire of the moon is altogether 
what it is here. It is true that we judge in a wholly different 
way of moons (which are satellites merely) than of the princi- 
pal planets. Kepler 2 has left a little book which contains an 
ingenious story upon the condition of the moon, and an Eng- 
lishman, 3 an liomme d'esprit, has published the humorous de- 
scription of a Spaniard (of his own invention) whom some birds 
of passage transported to the moon, not to mention Cyrano, 4 
who since went to find this Spaniard. Some clever men, wish- 
ing to present a beautiful picture of the other life, conduct 
very happy souls from world to world ; and our imagination 
finds therein a part of the agreeable occupations which may be 
ascribed to genii. But however it may strive, I doubt if it 
can attain its object, because of the great interval between us 
and these genii, and the great variety found therein. And 
until we find telescopes like those Descartes made us hope 
for in order to discern parts of the moon's sphere no larger 
than our houses, we cannot determine what there is in a globe 
different from ours. Our conjectures will be more useful and 

" last and best " ed., with notes and a critical account of the author's writing 
by the astronomer Jerome de la Lande, Paris, 1800, by Miss E. Gunning, 1803. 
Fontenelle was author also of Dialogues des morts, Paris, 1683 ; L'Histoire 
des Oracles, Paris, 1687 ; Doutes sur le systems physique des causes occasio- 
nelles, against Malebranche, Paris, 1686. — Tr. 

1 Jacques reads : " fort difficile." — Tr. 

2 Cf. ante, p. 123, note 2. The book of Kepler here referred to by Leibnitz 
is his Somnium seu de astronomia lunari, Francofurti, 1634, 4to, published 
after his death by his son, and found in Frisch, J. Kepleri opera omnia, Vol. 
8, Pt. I., pp. 21-39. The concluding paragraphs, pp. 38-39, are of a zoological 
and ethnological character. Michaud (Biog. Univ. 22, 313) says it is a philo- 
sophical and allegorical romance, in which tbe author exposes the astronomical 
phenomena as they would appear to the inhabitants of the moon, who like 
ourselves think that they are at the centre of the universe, but who are not so 
well situated as we to raise themselves to the "idea" of the true system. 
Schaarschmidt states that Kepler had occupied himself with Plutarch's De 
facie in orbe lunse (Eng. trans, in Plutarch's Morals, ed. Goodwin, 5, 234- 
292 — the Moon-Daemons, 289) and from the tales about tbe moon-daemons 
therein contained related by Sylla, had derived his idea of a lunar geography. 
— Tr. 

3 Franc. Godwin. Of. ante, p. 342, note 2. — Tr. 

4 Of. ante, pp. 228, note 2 ; 399, note 3. The reference is to his Voyage dans 
la lune. Cf. Theodicee, Pt. III., § 343; Gerhardt, 6, 318; Erdmann, 603 b; 
Jacques, 2, 268; Janet, 2, 359, 360; Dutens, 1, 364. —Tr. 



552 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

more true upon the internal parts of our bodies. I hope that 
we shall go beyond conjecture on many occasions, aud I already 
now believe that at least the violent agitation of the parts of the 
fire of which you just spoke should not be reckoned among the 
things which are only probable. It is a pity that the hypothesis 
of Descartes regarding the constitution (contexture) of the parts 
of the visible universe has been so little confirmed by the re- 
searches and discoveries since made, or that Descartes did not 
live fifty years later to give us an hypothesis upon the basis of 
present knowledge as ingenious as the one he gave upon the 
basis of the knowledge of his time. 1 - As for the gradual con- 
nection of species, we have said something concerning it in a 
preceding conference, in which I remarked that philosophers 
had already reasoned upon the vacuum in the forms or species. 2 
Everything goes by degrees in nature, and nothing by leaps, and 
this rule regarding changes is a part of my law of continuity. 3 
But the beauty of nature, which desires distinct perceptions, 
demands the appearance of leaps, and so to speak musical ca- 
dences in phenomena, and takes pleasure in mixing the species. 
Thus although there may be in some other world mediate spe- 
cies between man and beast (according as we understand these 
words), and although there may be somewhere rational animals 
surpassing us, nature has found it good to keep them away 
from us, in order to give us without contradiction the supe- 
riority we have in our globe. I speak of mediate species, and 
I should not wish to regulate myself here by human individ- 
uals, who approach the brutes, because apparently this is not 
a defect of faculty, but a hindrance to its exercise ; so that I 
think that the most stupid of men (who is not in a condition 
contrary to nature by reason of some disease or some other per- 
manent defect taking the place of the disease) is inconiparabty 
more rational and more docile than the most spiritual of all 

1 Leibnitz here refers to Descartes' theory of vortices, which he elaborated 
in his Principia Philosophise, Pts. III. and IV. A brief account of it will be 
found in the Eneyclop. Brit., 9th ed., article " Descartes," Vol. 7, pp. 107-108 
(American Reprint). Cf. also J. H. v. Kirchmann's German translation, with 
notes, of the Prin. Philos. (Vol. 26, Pt. I., of his Philos. Bibliothek.), 2d ed. 
Heidelberg, 1887. For other references of Leibnitz to the theory, cf. Ger- 
hardt, Leibniz, philos. Schrift., 4, 283, 288-289, 340 (Dutens, Leibnit. op. om., 
3, 252-253) , 348. — Tk. 

2 Cf. ante, p. 333-334. — Tr. 

3 Cf. ante, p. 334, note 1. — Tr,. - 



ch. xvi] ON HUMAN UNDERSTANDING 553 

the beasts, although the contrary is sometimes said by way of 
a -witticism. For the rest, I strongly approve the search for 
analogies : plants, insects, and the comparative anatomy of 
animals will furnish them more and more, especially if we 
continue to avail ourselves of the microscope still more than 
we have done. And in matters more general you will find 
that my views concerning the Monads diffused everywhere, 
their unending duration, the conservation of the animal with 
the soul, the perceptions undistinguished in a certain condi- 
tion, such as the death of simple animals, the bodies which 
it is rational to attribute to genii, the harmony of souls and 
bodies, which causes each to follow perfectly its own laws 
without being disturbed by the other and without the necessity 
of distinguishing therein the voluntary or the involuntary : you 
will find, I say, that all these views are entirely conformed to 
the analogy of the things which we observe and which I 
merely extend beyond our observations, without limiting them 
to certain portions of matter or to certain kinds of actions, and 
that the only difference therein is from the great to the small, 
from the sensible to the insensible. 

«■/§ 13. Ph. Yet there is one case where we defer less to the 
analogy of natural things which experience has made known 
to us, than to the contrary testimony of a strange fact which 
is far from it. For when supernatural events are conformed 
to the ends of him who has the power to change the course of 
nature, we have no reason for refusing to believe them when 
well attested, and this is the case of miracles which find not 
only belief for themselves, but give it also to other truths 
which need such confirmation. 1 § 14. Finally, there is a testi- 

1 Leibnitz here takes no notice of this remark of Locke concerning miracles, 
but expresses himself briefly on the subject in the New Essays, Preface, ante, 
p. 55, and Bk. IV., chaps. 17 ad fin., infra, p. 582, 19 ad fin., infra, p. 606 ; and 
more fully in the Theodicee, Discours preliminaire, etc., § 3, Gerhardt, 6, 50, 
Erdmanni 480, Jacques, 2, 26, Janet, 2, 34, Dutens, 1, 65, Pt. I., § 54, Pt. II., 
§§ 207, 208, Pt. III., § 249; Discours de metaphysique, 1686, §§ 7, 16, G. 4, 432, 
441 ; Remarques sur la lettre de M. Arnaud, May 13, 1686, G. 2, 40 ; Letters to 
Clarke, G.7, 352 sq., E. 746 sq., Js. 2, 414 sq., Jt. 2, 617 sq., D. 2, Pt. I., 110 sq., 
trans. Duucan, 238 sq., No. 1, § 4, No. 2, § 12, No. 3, §§ 13-17, No. 4, §§ 33, 40, 
42^5, No. 5, §§ 107, 109-113, 115-118 ; Response aux Objections contre le Systeme 
de I'harmonie preetablie qui se trouvent dans le livre [du P. Francois Lami] de 
la Oonnoissance de soy-meme, 1709, G. 4, 594, E. 460, D. 2, Pt. I., 100, and the 
Essay, first printed by Gerhardt, 4, 577-590, referring to the same book, and 
dated Berlin, Nov. 30, 1702, G. 4, 587 ; Letter to Tentzel, 1693, Dutens, 5, 401 ; 



554 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

mony which outweighs all other assent, viz. revelation, i.e. the 
testimony of God, who can neither deceive nor be deceived ; 
and the assent we give to it is called faith, which excludes all 
doubt as perfectly as the most certain knowledge. ^But the 
point is, to be assured that the revelation is divine, and to 
know that we understand its real sense ; otherwise, we are 
exposed to fanaticism and the errors of a false interpretation. 
And when the existence and the sense of revelation is only 
probable, the assent cannot have a greater probability than 
that found in the proofs. But we shall speak of this still 
farther. 

Th. Theologians distinguish between the motives of credi- 
bility (as they call them), together with the natural assent 
which must spring from them and which cannot have more 
probability than these motives, and the supernatural assent, 
which is an effect of the divine grace. Books have been 

Annotatiunculas subitanese ad Tolandi librum, De Christianismo mysteriis 
carente, written Aug. 8, 1701, Dutens, 5, 146, 148 ; Letters to Hartsoeker, Feb. 
6, 1711, G. 3, 517-518, D.2, Pt. II., 61, Dec. 7, 1711, G. 3, 529; Systema theologi- 
cum, written probably c. 1686, ed. C. Haas, Tubingen, 1860, p. 139. Cf. also 
the discussions by Pichler, Theol. d. Leibniz, 1, 226-237 ; K. Fiscber, Gesch. 
d. n. Philos., Bd. II., Leibniz, 3d ed., pp. 573-576; O. Pfleiderer, Religiow- 
philosophie, 2d ed., Berlin, 1883, Vol. 1, pp. 90-94, Eng. trans., Vol. 1, pp.91-93. 
Leibnitz — whether consistently or not with his philosophical system is 
fairly open to question — certainly admits the possibility, and upon sufficient 
and proper evidence the actuality, of miracles in the sense of personal acts of 
God in his universe, should a sufficient and proper reason therefor exist in 
God's mind. Such acts were not violations of law, but consisted simply in the 
substitution of a higher law for a lower, and the introduction of a new force 
in accord therewith.^ Leibnitz justifies his view thus: (1) The laws or order 
of nature are not metaphysical necessities, but positive truths, resting on the 
divine choice of the best as governed by the divine wisdom, and therefore 
amenable to the requirements of that wisdom, the physical always being 
subject to the moral order and purpose — " Cum natura rerum nihil aliud sit 
quam consuetudo Dei, ordinarie aut extraordinarie agere seque facile ipsi est, 
prout sapientia ejus exigit " (Syst. theol. p. 139, ed. Hass, Tub. 1860); (2) 
All these acts were foreseen as possible, and as such included in the original 
ideal world-plan by the divine intelligence, and therefore involve no change 
or inconsistency in that plan; cf. Discours de metaphys., § 7, G. 4, 432: 
" Or puisque rien ne se peut faire, qui ue soit dans l'ordre, on peut dire que les 
miracles sont aussi bien clans l'ordre que les operations naturelles, qu'on appelle 
ainsi parce qu'elles sont conformes a certaiues maximes subalternes que nous 
appellons la nature des choses." And he continues in language which would 
be quoted more appropriately as a parallel passage to that just cited from 
the Syst. theol. : " Car on peut dire que cette nature n'est qu'une coustume de 
Dieu, dont il se peut dispenser a cause d'une raison plus forte, que celle qui 
l'a mu a se servir de ces maximes." — Te. 



i] ON HUMAN UNDERSTANDING 



written expressly on the Analysis of Faith which do not alto- 
gether agree among themselves, but since we shall speak of 
this in the sequel, I do not wish to anticipate here what we 
shall have to say in its place. 



CHAPTEE XVII 

OF REASON 

§ i. Ph. Before speaking distinctly of faith, we shall treat 
of reason. It signifies sometimes clear and true principles, 
sometimes conclusions deduced from these principles, and some- 
times the cause, and particularly the final cause. Here we 
consider it as a faculty by which man is supposed to be dis- 
tinguished from the beasts and in which it is evident that he 
much surpasses them. § 2. We need it both to extend our 
knowledge 1 and to regulate our opinion, and it constitutes, 
properly understood, two faculties, sagacity, for the discovery 
of mediate ideas, and the faculty of drawing conclusions, or 
inference.^ § 3. We may consider in reason these four degrees : 
(1) the discovery of proofs ; (2) their orderly arrangement show- 
ing their connection; (3) the perception of the connection in 
each part of the deduction; (4) the drawing of the conclusion. 
We may observe these degrees in mathematical demonstrations. 

Th. The reason is the known truth whose connection with 
another less known makes us give our assent to the latter. But 
in particular and pre-eminently we call it reason, if it is the 
cause not only of our judgment, but also of the truth itself, 

1 Locke, and in agreement with him here Leibnitz, uses "reason," as 
Schaarschmidt says, not in the sense of the raO; of Plato and Aristotle, as the 
faculty of ideas and first principles, but in the sense of the Greek Adyo?, as the 
power or faculty of drawing conclusions, thus serving to extend our knowl- 
edge, a process which may be synthetic and deductive as well as analytic and 
inductive. The function of logic in regulating opinion as opposed to its func- 
tion in extending knowledge is the production of the logical arrangement of 
knowledge and the classification of concepts, both of which greatly influence 
the reasoning process and its result, and thereby effect both the extension of 
knowledge and the regulation of opinion. For a fuller exposition of Locke's 
view, cf. J. H. v. Kirchmann, Erlauterungen zu J. Locke's Versuch u. d. 
menschl. Verstand, No. 432, Vol. 52, Pt. II., pp. 105-108, of his Philos. 
Bibliothek, Berlin, 1874.— Tk. 



556 LEIBNITZ'S CRITIQUE OE LOCKE [bk. it 

which we also call reason a priori, and the cause in things corre- 
sponds to the reason in truths. This is why cause indeed is 
often called reason, and particularly final cause. Finally, the 
faculty which perceives this connection of truths, or the faculty 
of reasoning, is also called reason, and this is the sense you 
employ here. ISTow this faculty is really affected by man alone 
here below, and does not appear in other animals here below; 
for I have already shown above that the shadow of reason seen 
in the beasts is only the expectation of a similar event in a case 
apparently similar to the past, without knowing whether the 
same reason holds good. Men themselves act no differently in 
the cases where they are only empirical. But they raise them- 
selves above the beasts, in so far as they see the connections of 
truths, the connections, I say, which themselves indeed consti- 
tute the necessary and universal truths, v These connections are 
indeed necessary although they produce only an opinion, when 
after an exact research the prevalence of probability, so far as 
may be judged, may be demonstrated, so that then there is 
demonstration, not of the truth of the thing, but of the side 
prudence requires us to take. In dividing this faculty of 
reason, I think we do no wrong in recognizing two parts, 
according to a sufficiently received opinion which distinguishes 
invention and judgment. As for the four degrees which you 
remark in mathematical demonstrations, I find that usually the 
first, viz. : the discovery of proofs, does not appear therein, as 
is to be desired. There are syntheses, found sometimes with- 
out analysis, and sometimes the analysis has been suppressed. 
Geometers in their demonstrations put first the proposition 
which is to be proved, and in order to come to the demonstra- 
tion they set forth by some figure what is given. This is called 
ecthesis. After this they come to the preparation and draw new 
lines which they need in the reasoning ; and often the greatest 
art consists in finding this preparation. This done, they con- 
struct the reasoning itself, by drawing inferences from what 
was given in the ecthesis and from what has been added thereto 
by the preparation; and employing for this purpose truths 
already known or demonstrated, they reach the conclusion. 
But there are cases where they dispense with the ecthesis and 
the preparation. 

§ 4. Ph. It is generally believed that the syllogism is the 



ch. xvn] ON HUMAN UNDERSTANDING 557 

great instrument of reason and the best means of making nse 
of this faculty. For myself I doubt it, for it serves only to 
show the connection of proofs in one single example and no 
more; but the mind sees the connection as easily and perhaps 
better without it. Those who know how to use the figures and 
the moods most frequently take their use for granted by an 
implicit faith in their masters without understanding their 
reason. If the syllogism is necessary, no one knew anything 
whatever by reason before its invention, and it will be neces- 
sary to say that God having made man a two-legged creature, 
left it to Aristotle to make him a rational animal ; I mean from 
that small number of men that he could induce to examine the 
grounds of syllogisms, where among more than sixty ways of 
forming the three propositions there are only about fourteen of 
them valid. But God has been much kinder to men ; he has 
given them a mind capable of reasoning. I do not say this to 
lower Aristotle, whom I regard as one of the greatest men of 
antiquity, whom few have equalled in extent, subtility, pene- 
tration of mind, and strength of judgment, and who by the very 
fact that he has invented this brief system of the forms of 
argumentation has rendered a great service to savants against 
those who are not ashamed to deny everything. But yet these 
forms are not the only nor the best means of reasoning; and 
Aristotle did not find them by means of the forms themselves, 
but by the original way of the manifest agreement of ideas ; 
and the knowledge acquired of them in the natural order in 
mathematical demonstrations appears better without the aid 
of any syllogism. To infer is to draw a proposition as true 
from another already advanced as true, by supposing a certain 
connection of mediate ideas ; for example, from the proposition 
that men will be punished in another world, we infer that they 
can determine themselves here. Here is the connection: Men 
ivill be punished and God is the one who punishes; therefore 
punishment is just; therefore the punished is guilty; therefore 
he coidd have done otherwise; therefore he is free; therefore 
finally he has the power of self-determination. The connection 
is seen better here than if there were five or six involved 
syllogisms, in which the ideas would be transposed, repeated, 
and enshrined in artificial forms. The question is to know 
what connection a mediate idea has with the extremes in a 



558 LEIBNITZ'S CEITIQUE OF LOCKE [bk. iv 

syllogism; but this is what no syllogism can show. It is the 
mind which can perceive these ideas so placed by a kind of 
juxtaposition, and that too by its own view. Of what use 
then is the syllogism? It is of use in the schools where men 
are not ashamed to deny the agreement of ideas which plainly 
agree. Whence it comes that men never make syllogisms in 
their own inquiries after truth or in their teaching of those 
who sincerely desire to know it. It is quite plain, also, that 
this order is the more natural : — 

man — animal — alive ; 

i.e. man is an animal, an animal is alive, therefore man is 
alive, than that of the syllogism : — 

animal — alive, man — animal, man — alive; 

i.e. the, animal is alive, man is an animal, therefore man is 
alive. -'It is true that syllogisms may be of use in discovering 
a fallacy concealed under the brilliant splendor of an ornament 
borrowed from rhetoric, and I had sometimes thought that the 
syllogism was necessary, at least to guard against sophisms 
disguised under florid discourse.; but after a more severe 
examination, I have found that we have only to distinguish 
the ideas upon which the conclusion depends from those which 
are superfluous, and to arrange them in a natural order to show 
their incoherence. I knew a man to whom the rules of the 
syllogism were wholly unknown, who perceived at once the 
weakness and false reasoning of a long artificial and plausible 
discourse with which others better skilled in all the finesse of 
logic suffered themselves to be entrapped; and I believe- that 
there will be few of my readers who do not know such persons. 
If that were not so, princes in matters relating to their crown 
and dignity would not fail to introduce syllogisms into the most 
important discussions, where, however, everybody believes it 
would be a ridiculous thing to make use of them. In Asia, 
Africa, and America, among peoples independent of the Euro- 
peans, scarcely any one has ever been heard to speak of them. 
Finally, it is found after all that these scholastic forms are not 
less liable to error; people also are rarely reduced to silence 
by this scholastic method and still more rarely convinced and 
won. They will recognize at most that their adversary is more 



ch. xvii] ON HUMAN UNDERSTANDING 559 

adroit, but they do not cease to be persuaded of the justice of 
their cause. And if fallacies may be involved in the syllogism, 
the fallacy must be discovered by some other means than that 
of the syllogism. Yet I am not of the opinion that syllogisms 
are to be rejected or that we are to deprive ourselves of any 
means capable of aiding the understanding. There are eyes 
which need spectacles; but those who use them should not say 
that no one can see well without spectacles. This would be 
lowering nature in favor of an art, to which they are perhaps 
debtors. Unless it may have happened to them wholly con- 
trary to the experience of persons who have availed themselves 
too much or too soon of spectacles, so that they have so thor- 
oughly obscured their sight by means of them that they are no 
longer able to see without their aid. 
JTh. Your reasoning on the little use of syllogisms is full of 
a number of solid and fine remarks, and it must be admitted 
that the scholastic form of syllogisms is little employed in the 
world and that it would be too long and perplexing if one 
desired to employ it seriously. And yet, would you believe 
it, I consider the invention of the form of syllogisms one of 
the most beautiful, and also one of the most important, made 
by the human mind. 1 It is a species of universal mathematics 
whose importance is not sufficiently known; and it may be said 
that an infallible art is therein contained, provided we know and 
can use it, which is not always allowed. Now you must know 
that by arguments in form, I mean not merely this scholastic 
mode of argument used in colleges, but all reasoning which 
concludes by the force of the form, and in which there is no 
need of supplying anything, so that a sorites, another syllogistic 
series which avoids repetition, even an account well drawn up, 
and algebraic calculation, an infinitesimal analysis, will be for 
me almost arguments in form, because their form of reasoning 
has been predemonstrated, so that we are certain not to be 
deceived thereby. The demonstrations of Euclid most fre- 
quently come near being arguments in form; for when he 
apparently produces entliymemes, the proposition suppressed 
and seemingly lacking is supplied by the citation on the mar- 
gin where is given the means of finding it already demonstrated; 

1 Cf. ante, p. 379, note 2. The letter to G. Wagner is Leibnitz's most com- 
plete expression of his estimate of the worth of formal logic. — Tr. 



560 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

this gives a great abstract without taking anything from its 
force. These inversions, compositions, and divisions of reasons 
which he makes use of are only the species of forms of argu- 
mentation peculiar and characteristic of the mathematicians 
and to the matter they treat; and they demonstrate these forms 
with the aid of the universal forms of logic. Further, you must 
know that there are good asyllogistic conclusions which also 
cannot be rigorously demonstrated by any syllogism without 
changing somewhat its terms; and this change itself of terms 
makes the conclusion asyllogistic. There are several of these, 
as among others, a recto ad ooliquum; for example, Jesus Christ 
is God; therefore the mother of Jesus Christ is the mother of 
God. Again, that which clever logicians have called inversion 
of relation, as, for example, this conclusion: if David is the 
father of Solomon, without doubt Solomon is the son of David. 
These conclusions do not cease to be demonstrable by the truths 
on which the common syllogisms themselves depend. Syllo- 
gisms also are not merely categorical, but also hypothetical, in 
which are comprised the disjunctives. And we may say that 
the categorical are simple or complex. The simple categoricals 
are those which are usually reckoned, i.e. according to the 
moods of the figures; and I have found that the four figures 
have each six moods, so that there are twenty-four moods in 
all. The four common moods of the first figure are only the 
result of the meaning of the signs, All, No, Some. And the 
two which I add to them in order to omit nothing are only 
the subalterns of the universal propositions. For of these two 
ordinary moods, All B is C, and all A is B, therefore all A is 
C ; again, No B is C, All A is B, then no A is C, we make these 
two additional moods, All B is C, All A is B, then some A is C ; 
again, No B is C, All A is B, then some A is not C. For it is 
not necessary to demonstrate the subaltern and to prove its 
conclusions : All A is C, then some A is C ; again, No A is C, 
then some A is not C, although we may, however, demonstrate 
it by the identicals joined with the moods already received of 
the first figure, in this way : All A is C, Some A is A, then 
some A is C ; again, No A is C, Some A is A, then some A is 
not C. So that the two additional moods of the first figure are 
demonstrated by the first two ordinary moods of the said figure 
with the intervention of the subaltern, itself demonstrable by 



en. xvii] ON HUMAN UNDERSTANDING 501 

the other two moods of the same figure. 1 In the same way the 
second figure receives also two new ones. Thus the first and the 
second have six ; the third has had six always ; the fourth was 
given five, but it is found to have six also by the same principle 
of addition. But we must know that logical form does not 
bind us to this order of propositions which we commonly use, 
and I am of your opinion, sir, that this other arrangement is 
superior in value : All A is B, All B is C, therefore all A is C, 
which would be particularly by the sorites, which are a chain 
of such syllogisms. For if there were one more of them: All 
A is C, All C is D, therefore all A is D, we may make a chain 
of these two syllogisms, which avoids the repetition by saying : 
All A is B, All B is C, All C is D, therefore all A is D, wherein 
we see that the useless proposition All A is C is neglected, and 
the useless repetition of this same proposition which the two 
syllogisms would demand is avoided; for this proposition is 
henceforth useless, and the chain is an argument perfect and 
in good form without this same proposition when the force of 
the chain of reasoning has once for all been demonstrated by 
means of these two syllogisms. There is an infinite number 
of other chains of reasoning more complex, not only because 
a greater number of simple syllogisms enter therein, but also 
because the ingredient syllogisms exhibit greater differences 
among themselves, for there may be made to enter into them 
not only simple categoricals, but also copulatives, and not 
only categoricals, but also hypotheticals ; and not only com- 
plete syllogisms, but also enthymemes, wherein the propo- 
sitions believed evident are suppressed. And all this joined 
with the asyllogistic conclusions, and with the transposi- 
tions of the propositions, and with a multitude of turns and 
thoughts which conceal these propositions through the natural 
inclination of the mind to abridge, and by the properties of 
language appearing in part in the employment of the parti- 
cles, will make a chain of reasoning which will represent 
the entire argumentation indeed of an orator, but emaciated 

1 Cf. Difficultates qusedam logicx, Gerhardt, 7, 211-217, Erdmann, 101-104; 
also Leibnitz's letter to Bourguet, March 22, 1714, G. 3, 569-70, E. 723 b. 
The youthful demonstration referred to in this letter is found in the Dis- 
sertatio de Arte Combinatoria, 1666, Problem II., § VI., G. 4, 46 sq., E. 13 b. 
sq., Dutens, 2, Pt. I., 352 sq., and is Leibnitz's most thorough and elaborate 
treatment of the moods and figures of the syllogism. — Te. 
2o 



562 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

and stripped of its ornaments and reduced to logical form, not 
scholastically, but always sufficiently to recognize its force, 
according to the laws of logic, which are none else than those 
of good sense, placed in order and in writing, and which differ 
no more than the custom of a province differs from what it had 
been when from unwritten as it was, it has become written, 
except that being put in writing and being capable of being 
better seen at once, it furnishes more light to enable it to be 
pushed and applied ; for natural good sense without the aid of 
art, making the analysis of certain reasoning, will sometimes 
be a little in trouble regarding the force of conclusions, finding 
some, for example, which include some mood, valid for truth 
but less ordinarily used. But a logician who wished us not to 
make use of such series, or wished not to make use of them 
himself, claiming that we must always reduce all the complex 
arguments to the simple syllogisms on which in fact they de- 
pend, would be, according to what I have already said to you, 
like a man who wished to compel the merchants of whom he 
buys something to count for him the numbers one by one, as we 
count on the fingers, or as we count the hours of the town-clock ; 
a procedure which would indicate his stupidity, if he could not 
count otherwise, or if he could discover only at his fingers' 
ends that five and three make eight, or rather it would indicate 
a caprice if he knew these short methods and did not wish to use 
them or to allow us to use them. He would be also like a man 
who wished us not to employ axioms and theorems already 
demonstrated, claiming that we must always reduce all reason- 
ing to first principles in which is seen the immediate connection 
of the ideas upon which in reality these mediate theorems 
depend. 

J After having explained the use of the forms of logic in the 
way in which I think it should be understood, I come to your 
considerations; and I do not see, as you wish, sir, that the 
syllogism serves merely to exhibit the connection of proofs in a 
single example. To say that the mind always sees easily the 
conclusions, is a statement which will not be found true ; for 
we sometimes see some (at least in the reasonings of another) 
where there is room for doubt at first so long as their demon- 
stration is not seen. Ordinarily, we use examples to justify 
conclusions, but this method is not always sufficiently sure, 



ch. xvn] ON HUMAN UNDEESTANDING 563 

although there is an art of choosing examples which would not 
be found true if the conclusions were not valid./ I do not 
believe it would be permitted in well-governed schools to deny 
without any shame the manifest agreement of ideas, and it does 
not appear to me that we employ the syllogism to show them. 
At least this is not its unique and principal use. You will find 
oftener than you think (in examining the paralogisms of 
authors) that they have sinned against the rules of logic, and 
I have myself found by experience sometimes in discussion, 
even by writing, with persons of good faith, that we began to 
be understood only when we argued in form in order to disen- 
tangle a chaos of reasonings. It would without doubt be ridic- 
ulous to wish to argue after the scholastic fashion in important 
deliberations, because of the importunate and embarrassing 
prolixities of this form of reasoning, and because it is like 
counting on the fingers. But yet it is only too true that in the 
most important deliberations regarding life, the state, salva- 
tion, men allow themselves to be dazzled often by the weight 
of authority, by the gleam of eloquence, by examples badly 
applied, by enthymemes falsely supposing the evidence of that 
which they suppress, and even by faulty conclusions ; so that a 
severe logic, but of another turn than that of the School, would 
be only too necessary for them, among other things, to deter- 
mine upon which side is the greatest probability. For the 
rest, the fact that the common herd of men ignore artificial 
logic, and that they do not cease thereby to reason well and 
sometimes better than the class practised in logic, this fact 
proves not its inutility any more than it would prove the 
inutility of artificial arithmetic, because we see that some per- 
sons count well on ordinary occasions without having learned 
to read or write and without knowing how to handle the pen or 
the tokens as far as to rectify the errors of another who has 
learned to calculate, but who may be neglectful or confused in 
the characters and signs. It is true that syllogisms also may 
become sophistical, but their own laws serve to recognize them; 
and syllogisms do not convert or indeed conquer always ; but 
this is because the abuse of distinctions and of badly understood 
terms renders their use prolix until it becomes insupportable, 
if it must be driven to extremities. 

It remains for me here only to consider and to supplement 



564 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

your argument, employed as an example of clear reasoning 
without the form of the logicians: God punishes man (an 
assumed fact) ; God punishes justly the one he punishes (a truth 
of reason which may be regarded as demonstrated) ; therefore 
God punishes man justly (a syllogistic conclusion extended 
asyllogistically a recto ad obliguum) ; therefore man is justly 
punished (an inversion of relation, but which is set aside 
because of its evidence) ; therefore man is guilty (an enthymeme, 
in which is suppressed this proposition which in reality is only 
a definition : he who is punished justly is guilty) ; therefore man 
could have done differently (a suppression of this proposition : 
he who is guilty could have done differently) ; therefore man 
was free (a further suppression: he who could have done differ- 
ently was free) ; therefore (by the definition of freedom) he had 
the power of self-determination ; which was to be proved. Ee- 
garding which I remark further that this therefore itself 
includes in reality both the unexpressed proposition (that he 
who is free has the power of self-determination) and is useful 
in avoiding the repetition of terms. And in this sense noth- 
ing would be omitted, and the argument in this view might pass 
as complete. You see that this reasoning is a series of syllo- 
gisms entirely in accord with logic ; for I do not now wish to 
consider the matter of this reasoning, wherein there might per- 
haps be some remarks to make or some explanations to demand. 
For example, when a man cannot do differently, there are some 
cases in which he might be guilty before God, as if he were 
very glad to be unable to aid his neighbor in order to have an 
excuse. To conclude, I admit that the scholastic form of 
arguing is ordinarily inconvenient, insufficient, badly managed, 
but I say at the same time that nothing would be more impor- 
tant than the art of arguing in form according to true logic, 
i.e. fully as to matter and clearly as to the order and force of 
the conclusions, whether self-evident or predemonstrated. 

§ 5. Ph. I thought that the syllogism would be still less 
useful, or rather of absolutely no use in probabilities, because 
it pushes only a single topical argument. 1 But I see now that 

1 Aristotle, Topics, I., 1, 100° 27 sq., designates the "topical argument" as 

6 SiaAeKTiKOs eruAAoyio>«k, or o e'£ evSoguv av\\oyi£6ixevo<;, i.e. the dialectic Syllo- 
gism, or the syllogism which reasons from the probahle in distinction from 
aTToSeifis, or the proof resting upon and leading back to first and necessary 



ch. xvn] ON HUMAN UNDERSTANDING 565 

it must always furnish solid proof of what is certain in the 
topical argument itself, i.e. the probability therein found, and 
that the force of the conclusion consists in the form. § 6. But 
if syllogisms serve 'only in judging, I doubt whether they are 
capable of use in invention, i.e. in finding proofs and making 
new discoveries. For example, I do not think that the dis- 
covery of the 47th proposition of the first book of Euclid is due 
to the rules of ordinary logic, for we first know it and then are 
able to prove it in syllogistic form. 

v'Th. Comprising under syllogisms also the series of syllo- 
gisms and everything which I call formal argumentation, we 
may say that knowledge, not self-evident, is acquired by infer- 
ences which are valid only when they have their due form . In 
the demonstration of the said proposition which makes the 
square of the hypothenuse equal to the squares of the two 
sides, we divide the large square into parts and likewise the 
two small ones, and we find that the parts of the two small 
squares may all be found in the large one and neither more nor 
less. This is the proof of equality in form, and the equality 
of the parts is also proved by arguments in valid form. The 
analysis of the ancients was, according to Pappus, to take what 
is asked and to draw therefrom conclusions until they come to 
something given or known. I have remarked that for this 
result the proposition must be reciprocal in order that the 
synthetic demonstration may return in the contrary direction 
by the paths of analysis, but it is always a drawing of conclu- 
sions. It is well, however, to remark here that in astronomical 
or physical hypotheses the return does not take place ; but in 
like manner success does not demonstrate the truth of the 
hypothesis. It is true it renders it probable, but as this proba- 
bility appears to violate the rule of logic which teaches that 
the true may be drawn from the false, it will be said that 
logical rules will not have entire sway in probable questions. 
I reply that it is possible for the true to be concluded from the 

truths. Cf. also Topics, VIII., 11, 162<* 15, where he calls the a-vWoyia-^ 
Sia\eKTiKd? an ewix^prifj.a or attempted proof, and the o-uAAoyio-/xb; dn-oSeiKTiicds a 
(£iAoo-o<f>T)|ua or demonstration. On the whole subject, cf. Zeller, Philos. d. 
Griech., II., 2 [Vol. 4], 242 sq., 3d ed., 1879; Prantl, Gesch. d. Logih, 1, 95 sq.; 
Wallace, Outlines of the Philos. of Aristotle, § 23, pp. 47-48. Cf. also, New 
Essays, Bk. II., chap. 21, § 66, Th. (2), ante, p.'214, note 1; Bk. IV., chap. 2, 
§ 14, Th., ante, p. 418, note 4. — Tu, 



566 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

false, but it is not always probable, especially when a simple 
hypothesis gives a reason for many truths, a thing which is 
rare and difficult to find. We might say with Cardan, 1 that the 
logic of the probable has other consequences than the logic of 
the necessary truths. But the probability itself of these con- 
clusions must be demonstrated by the conclusions of the logic 
of the necessary truths. 

§ 7. Ph. You appear to apologize for common logic, but I 
see clearly that what you bring forward belongs to a more 
sublime logic, to which the common is only what the alphabet 
is to scholarship : a fact which makes me remember a passage 
of the judicious Hooker, who in his book entitled "Ecclesiasti- 
cal Polity," Book I., § 6, thinks that if we could furnish the true 
helps of knoivledge and of the art of reasoning, which in this age 
passing as enlightened are not much known and for which 
people put themselves to very little trouble, there would be as 
much difference as regards maturity of judgment between men 
who would make use of them and what men now are, as between 
the men of the present and imbeciles. 2 I wish that our con- 
ference may give occasion to some to make a discovery of these 
true helps of the art of which this great man who had so pene- 
trating a mind speaks. They will not be the imitators who like 
the cattle follow the beaten track (imitatorum servum pecus). 3 

1 Girolamo Cardano, 1501-1576, an Italian physician, mathematician, and 
philosopher, whose complete works appeared at Lyons, 1663, 10 vols., fol., and 
an account of whose philosophy will he found in Stockl, Gesch. d. Philos. d. 
Mittelalters, III. [Vol. 4] , 452-458. — Tr. 

2 Richard Hooker, 1553-1600, attempted, in his Laios of Ecclesiastical 
Polity, to defend the Episcopal form of government of the Church of Eng- 
land, as established by the Protestant sovereign and Parliaments, against the 
attacks of the Presbyterians. To this end he gives in the two first books of 
his work an exposition of the fundamental principles by which the disputed 
question should be decided, especially of the nature of law in general, as a 
philosophical basis for the rest of his discussion. It is this portion of his 
work that gives it its permanent place and value in English literature and 
philosophy. 

The passage here referred to by Locke and Leibnitz runs thus, Eccles. 
Pol., Bk. I., chap. 6, § 3, Works, ed. Isaac Walton, Oxford, Univ. Press, 1841, 
2 vols., 8vo, Vol. 1, p. 164 : " Wherefore if afterwards there might be added 
the right helps of true art and learning (which helps, I must plainly confess, 
this age of the world, carrying the name of a learned age, doth neither much 
know nor greatly regard) , there would undoubtedly be almost as great dif- 
ference in maturity of judgment between men therewith inured, and that 
which men now are, as between men that are now and innocents." — Tr. 

3 Cf. Horace, Epist., 1, 19, 19. —Tr. 



ch. xvn] ON HUMAN UNDERSTANDING 567 

Yet I dare say there are in this age some persons of such 
strength of judgment and of such large extent of mind, that 
they could discover new paths for the advance of knowledge, 
if they would take the trouble to turn their thoughts in that 
direction. 

>> Th. You have well remarked, sir, with the late Mr. Hooker, 
that the world troubles itself but little about this ; otherwise 
I think there are and have been persons capable of succeed- 
ing therein. We must admit, however, that now we have 
great helps both on the side, of mathematics and of philoso- 
phy, in which the Essay concerning Human Understanding 
of your excellent friend is not the least. We shall see if 
we may not be able to profit therefrom. 

§ 8. Ph. I must further tell you, sir, that I have believed that 
there was a visible mistake in the rules of the syllogism ; but 
since we have conferred together you have made me hesitate. 
I will, however, set before you my difficulty. It is stated that 
no syllogistic reasoning can be conclusive unless it contaiyis at least 
one universal proposition. 1 But it seems that there are in the 
syllogism only particular things, which are the immediate 
object of our reasonings and knowledge; they revolve only 
about the agreement or disagreement of ideas, each of which 
has only a particular existence and represents only an individ- 
ual thing. 

Tli. As far as you conceive the similarity of things you con- 
ceive something more, and the universality consists only in 
that. Yet you will never propose to me any one of our argu- 
ments without therein employing the universal truths. It is, 
however, well to remark that (as far as form is concerned) the 
particular propositions are comprised within the universals. 
For although it is true that there is only a single St. Peter the 

1 Locke's sensistic realism appears in sharp outlines in the present passage 
and its immediate context; cf. further, Locke, Philos. Wks., Vol. 2, pp. 295- 
296. He maintains the existence, and consequently the knowledge, of the par- 
ticular and individual only, and that our reasoning, which relates to the 
agreement or disagreement of things, must accordingly, in order to hit the 
mark, confine itself to the particular. Leihnitz argues, on the other hand, 
that our knowledge of things, while beginning with the particular in the 
sense-act, does not rest there, hut through thought, especially through the 
medium of the linguistic form of our mental creation, gives to the individual 
and particular at once the character of universality. With Locke the ele- 
ment of universality is accidental ; with Leibnitz it is essential. — Tr. 



568 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

apostle, we may nevertheless say that whoever was St. Peter 
the apostle denied his master. Thus this syllogism : St. Peter 
denied his master, St. Peter was a disciple, therefore some 
disciple denied his master (although it has only particular 
propositions), is considered to have them as universal affirma- 
tives, and the mood will be Darapti of the third figure. 1 

Ph. I wished also to say to you that it appeared to me better 
to transpose the premises of the syllogisms and to say: All A 
is B, All B is C, therefore All A is C, than to say : All B is C, 
All A is B, therefore All A is C. But it seems from what you 
have said that they do not differ, and that both are counted as 
one and the same mood. It is always true, as you have 
remarked, that the disposition different from the common is 
better adapted to making a chain of several syllogisms. 

Th. I am wholly of your opinion. It seems, however, that 
the belief has been that it was more didactic to begin with 
universal propositions like the majors in the first and second 
figures; and there are indeed orators who have this custom. 
But the connection appears better as you propose. I have 
before remarked that Aristotle may have had a particular 
reason for the common disposition. Por instead of saying A 
is B, he was wont to say B is in A. And with this method of 
statement, the connection itself which you demand will arise 
for him in the received disposition. Por, instead of saying B 
is C, A is B, therefore A is C, he will state it thus : C is in B, 
B is in A, therefore C is in A. For example, instead of saying : 
The rectangle is isogon (or has equal angles), the square is a 
rectangle, therefore the square is isogon, Aristotle, without trans- 
posing the propositions, will preserve the middle place to the 
middle term by this method of stating the propositions, which 
reverses the terms, and will say : The isogon is in the rectangle, 
the rectangle is in the square, therefore the isogon is in the square. 
And this mode of statement is not to be despised, for in reality 

1 Peter being the middle term, and disciple the subject of the conclusion, 
the minor premise must be converted, by which process the universal affirma- 
tive, "St. Peter was a disciple," becomes the particular affirmative, "Some 
disciple was St. Peter," from which the particular conclusion, " Some disciple 
denied his master," immediately follows. The mood Darapti of the third 
figure thus becomes the mood Darii of the first. The universality of the 
premises consists in the fact that Peter constitutes the entire class to which 
he belongs. Of. Hamilton, Logic, Boston, 1873, pp. 314-315. — Tr. 



ch. xvii] ON HUMAN UNDERSTANDING 569 

the predicate is in the subject, or rather the idea of the predi- 
cate is included in the idea of the subject. For example, the 
isogon is in the rectangle, for the rectangle is the figure all of 
whose right angles are equal to each other, therefore in the 
idea of the rectangle is the idea of a figure all of whose angles 
are equals, which is the idea of the isogon. The common mode 
of statement regards rather individuals, but that of Aristotle 
ideas or universals. For in saying, every man is an animal, I 
mean to say that all men are included in all animals ; but I 
mean at the same time that the idea of animal is included in 
the idea of man. Animal includes more individuals than man, 
but man includes more ideas or more formalities ; ] the one has 
more examples, the other more degrees of reality ; the one more 
extension, the other more intension. It may also be truly said 
that the entire syllogistic doctrine may be demonstrated by 
that de continente et contento, the containing and the contained, 
which is different from that of the whole and the part; for the 
whole always exceeds the part, but the containing and the 
contained are sometimes equal, as is the case in reciprocal 
propositions. 2 

v § 9. Ph. I begin to form for myself a wholly different idea 
of logic from that I formerly had. I regarded it as a scholar's 
diversion, but I now see that, in the way you understand it, it 
is like a universal mathematics. Would to God that it might 
push on to something more than it yet is, in order that we 

1 I.e. essences. " The formality of the vow lies in the promise made to 
God." — Stillingfleet. — Tk. 

2 Leibnitz's thought, as Schaarschmidt says, is that sometimes the princi- 
ple, what is predicable of the whole is predicable of the parts — ab universali 
ad particulare consequentia valet — is not applicable, as in cases where the 
concepts found in the conclusion are coordinate rather than subordinate, 
i.e. coincident or identical in extension. In such cases the coordination or 
coincidence of the concepts — prineipium identitatis — might be adduced as a 
fundamental logical principle. To avoid this, Leibnitz proposes the principle 
De continente et contento, in which\in a certain sense is given the higher 
unity of subordination and identity, i.e. the subject may always be thought 
of as contained in the predicate, although coincident with it in extension. 
The principle, however, necessarily considers "the containing" as more ex- 
tended than the " contained." Cases such as Leibnitz here refers to, in which 
the coordination or agreement of terms is such as to make them identical — 
"important cases" "for the most part strangely overlooked" by logicians 
(Jevons, Lessons in Logic, p. 124, new ed., 1880) — are discussed by Jevons in 
his little work entitled The Substitution of Similars, London, Macmillan & Co., 
1869. — Tr. 



570 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

might be able to find thereby these true helps of reason of which 
Hooker spoke, which would raise men far above their present 
condition. Reason is a faculty which so much the more needs it, 
as its extent is quite limited and as it fails us in many instances. 
(1) Because often ideas themselves fail us. § 10. Then (2) they 
are often obscure and imperfect; whilst where they are clear 
(and distinct), as in numbers, we find no insurmountable diffi- 
culties, and fall into no contradiction. § 11. (3) Often also 
the difficulty comes from the fact that mediate ideas are want- 
ing. You know that before algebra, that great instrument and 
noteworthy proof of human sagacity, was discovered, men 
regarded with amazement^ many demonstrations of the ancient 
mathematicians. §12. It also happens (4) that the mind builds 
upon false principles, which may entangle it in difficulties 
where the reason is more involved and very far from clearing 
them up. § 13. Finally (5), terms whose meaning is uncertain 
embarrass the reason. 

Th. I do not know whether we so much lack ideas as you 
think, that is to say, distinct ideas. As for confused ideas, or 
rather images, or, if you prefer, impressions, as colors, tastes, 
etc., which are a resultant of many little ideas distinct in 
themselves, but of which we are not distinctly conscious, we 
lack an infinite number of them suitable to other creatures 
rather than to ourselves. But these impressions also serve 
rather to give rise to the instincts and to establish the observa- 
tions of experience than to furnish matter-to the reason, except 
so far as they are accompanied by distinct perceptions. It is 
then principally the defect of the knowledge we have of these 
distinct ideas, concealed within the confused, that stops us, 
and even when all is distinctly exposed to our senses or to our 
mind, the multitude of things that must be considered some- 
times perplexes us. For example, when there is a pile of one 
thousand cannon-balls before our eyes, it is plain that in order 
properly to conceive the number and properties of this multi- 
tude, it is very useful to arrange them in figures' as is done in 
the magazines in order to have distinct ideas of them and to 
fix them, indeed, so that we Taaj be spared the trouble of 
counting them more than once. It is the multitude of consid- 
erations also which causes some very great difficulties in the 
science of numbers themselves; for short methods are sought 



en. xvn] ON HUMAN UNDERSTANDING 571 

and sometimes we do not know whether nature has them within 
its folds for the case in question. For example, what is 
apparently simpler than the notion of the prime number? i.e. a 
whole number indivisible by every other except unity and 
itself. Yet we seek also a positive and easy sign in order to 
recognize them certainly without trying all the prime divisors 
less than the square root of the given prime. There are a 
number of signs which make known without much calculation 
that a given number is not prime, but we ask for one which is 
easy and which makes known certainly that it is prime when 
it is so. This it is which also makes algebra as yet so imper- 
fect, although nothing is better known than the ideas of which 
it makes use, since they signify only numbers in general; for the 
public has not yet the means of extracting the irrational roots 
of any equation beyond the fourth degree 1 (excepting in a very 
limited case), and the methods which Diophant,' 2 Scipio Ferreus, 3 

1 In Leibnitz's day, as the text states, equations of the 2d, 3d, and 4th 
degrees were reduced to pure equations, but the reduction of equations of 
higher degrees than the 4th remained an unsolved problem, on which mathe- 
maticians spent much labor, until Niels Henrik Abel, 1802-1829, a Norwegian 
mathematician of great ability and acuteness, demonstrated (1824) that the 
quintic equation and a fortiori the general equation of any order higher than 
five, is incapable of solution by radicals. Cf. Abel, Demonstration de Vim- 
possibilite de la resolution algebnque des equations generates qui passent le 
quatrieme degre, in CEuvres completes, ed. by Holmboe, 2 vols., Christiania, 
1839, Vol. 1, pp. 5-24, and hi Crelle, "Journ. f. Math.," 1826, Vol. 1, pp. 
65-84.— Tr. 

2 Diophantus, c. 325-c. 409, a celebrated Greek mathematician of the 
Alexandrian school, gave, in his Arithmeticorum lib. VI., a method for the 
solution of equations of the 1st and 2d degrees. The Ms. of his Arithmetic 
was discovered in 1460 in the Vatican Library by the astronomer Regiomon- 
tanus, 1436-1476, and was published in a Latin trans., without the original, by 
Xylander, in 1575. The Greek text, with a more complete trans., and a com- 
mentary by Bachet de Merzeriac, whose skill in indeterminate analysis 
especially fitted him for the task, appeared in 1621. The best ed., based upon 
that of Bachet, including the Greek text with Latin trans., is that by Pierre 
Fermat, 1601-1665, the celebrated French mathematician, who supplemented 
the commentary of Bachet by valuable notes of his own. It is found in Vol. 
1, pp. 65-341 of Fermat, Opera Mathematica, 2 vols., fol., Tolosae, 1670, 1679. 
-Tr. 

3 Scipione del Ferro or Ferri, c. 1465-1525, an Italian mathematician, taught 
arithmetic and geometry at Bologna from 1496 till his death. About 1505 he 
discovered the solution of a particular case of cubic equations, which he did 
not publish, but communicated to his favorite pupil Antonio del Fiore, who in 
1635 challenged Tartaglia to a trial of skill in resolving algebraical problems 
requiring a knowledge of this rule. Tartaglia in 1630 had already solved two 
cases of cubic equations, and before the time for the contest came solved two 



572 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

and Lewis Ferrari 1 used respectively for the second, third, 
and fourth degrees in order to reduce them to the first, or 
in order to reduce an affected equation to a pure, are wholly 
different from each other, i.e. that which is used/for one degree 
differs a degree from that used for another. /For the second 
degree, or the quadratic equation, is reduced to the first by 
merely eliminating the second term. The third degree, or the 
cubic equation, has been solved, because in separating the 
unknown quantity into parts there happily arises from these 
an equation of the second degree. And in the fourth degree, 
or the biquadratics, something is added to the two sides of the 
equation to render it capable of extraction on both sides, and 
then it is happily found that to obtain this result an equation 
of the third degree only is needed. But all this is only a mix- 
ture of good luck or chance with art or method. And in trying 
it on these last two degrees we knew not whether it would be 
successful. Further still, another artifice is necessary to suc- 
cess in the fifth or sixth degree, which are the sursolids or 
bicubes. -And although Descartes believed that the method he 
used in the fourth, conceiving the equation as produced by two 
other quadratic equations (but which cannot at bottom give 
more than that of Lewis Ferrari), would succeed also in the 
sixth, it is not found to be so. This difficulty shows that even 
the clearest and most distinct ideas do not always give us all 
we ask for and all that may be drawn from them. And this 
makes us also judge that algebra is very far from being the art 

more. He thus easily won the victory, as his problems could be solved only 
by one or the other of his own three rules which were unknown to Fiore, and 
not by the remaining rule which was the only one known to Fiore. Tartaglia's 
discoveries were improved and published by Cardan in connection with his 
own in 1545, as a supplement to a treatise on arithmetic and algebra pub- 
lished in 1539. Cf. Cardan, Opera omnia, Vol. 4, pp. 249-264. On Ferro, cf. 
Libri, Hist, des Sciences Math, en Italie, Vol. 3, pp. 148-151 ; Montucla, Hist, 
des Math., Vol. 1, p. 479, ed. 1758, Vol. 1, p. 591, ed. 1799-1802. — Tr. 

1 Ludovico or Luigi Ferrari, 1522-1562, or 1565, an Italian mathematician, a 
pupil of Cardano (cf. ante, p. 566, note 1), and Professor of Mathematics at Milan 
and at the University of Bologna, discovered the demonstration of the formula 
for the resolution of equations of the 3d degree, sent by Tartaglia, c. 1500-1557, 
to Cardan under the form of an enigma, and shortly after this discovery solved 
equations of the 4th degree. For an account of his demonstration, cf. Cardan, 
Ars magna, 1545, chap. 15. De cubo et quadratis sequalibus numero, § 3, 
Opera omnia, 10 vols., Lugduni, 1663, Vol. 4, p. 254. On Ferrari, cf. Libri, 
Hist, des Sciences Math, en Italie, Vol. 3, pp. 180, 181; Montucla, Hist, des 
Math., Vol. 1, pp. 484, 485, ed. 1758, Vol. 1, pp. 596, 597, ed. 1799-1802. —Tr. 



ch. xvn] ON HUMAN UNDEESTANDING 573 

of invention, since it needs a more general art; and we may 
say, indeed, that the art of signs (Specieuse) in general, i.e. the 
art of characters, is a marvellous means of assistance, since it 
aids the imagination. t/Lt will not be doubted in view of the 
arithmetic of Diophant and the geometrical books of Apollonius 
and Pappus that the ancients possessed it to a certain extent. 
Vieta 1 has given it more extension by expressing not only what 
is asked for, but also the given numbers, by general characters, 
doing in calculating what Euclid already did in reasoning, and 
Descartes has extended the application of this calculus to 
geometry, indicating lines by equations. Nevertheless, even 
after the discovery of our modern algebra, Bouillaud 2 (Ismael 
Bullialdus), no doubt an excellent geometer, whom, moreover, 
I knew in Paris, regarded only with wonder the demonstrations 
of Archimedes upon the spiral, and could not understand how 
this great man had thought of employing the tangent of this 
line as the dimension of the circle.^ Father Gregory of St. 
Vincent 3 appears to have divined it, thinking that it was at- 
tained by the parallelism of the spiral and the parabola. But 
this method is only a particular one, whilst the new calculus 
of infinitesimals 4 which proceeds by the method of the differ- 
ences which I have thought of and successfully shared with the 
public, gives a general one, wherein this discovery concerning 

1 Cf. ante, p. 468, note 1. — Tr. 

2 Ismael Boulliau, 1605-1694, a French mathematician and astronomer, who 
was the first to give, in his Ad astronomos monita duo, 1657, a plausible ex- 
planation of the change in the light of some stars by attributing to them an 
axial revolution which shows successively their obscure and luminous parts. 
He was the author of several works, among which is the Be lineis spiralibus 
demonstrationes, 1657, which Leibnitz, perhaps, had in mind here. — Tr. 

3 Gregoire de Saint-Vincent, 1584-1667, a Flemish geometer who was much 
occupied with the problem of the quadrature of the circle, and whose prin- 
cipal work is the Opus geometricum quadratures circuit et sectionum coni, 
1647. — Tr. 

4 For Leibnitz's account of his discovery of the " calculus of infinitesimals," 
cf. his Historia et origo calculi diferentialis, Gerhardt, Leibniz, math. Schrift, 
II., 1 [Vol. 5], 392-410; also his" letter, April 18, 1716, to the Countess Kiel- 
maunsegge, Dutens, Leibnit. op. om., 3, 456-461. For Leibnitz's various writ- 
ings on the subject, cf. Gerhardt, op. cit., II., 1 [Vol. 5] , 141-418 ; Dutens, op. cit., 
Vol. 3, passim. Dutens, Vol. 3, contains also much material concerning the 
controversy between Leibnitz and Newton regarding the discovery of the 
calculus. Further accounts are given in Guhrauer, Leibnitz, Eine Biographic, 
1, 286-320, Jaucourt, Historia vitse Leibnitii, and Montucla, Hist. d. Math., 
Vol. 2 (both in Dutens, op. cit. Vol. 3, pp. xii-xl, xli-lv), and in Encyclop. 
Brit., 9th ed., Vol. 13, Article, " Infinitesimal Calculus." — Tr. 



574 LEIBNITZ'S CEITIQUE OF LOCKE [bk. iv 

tlie spiral is mere play and a sample of the easiest, like nearly- 
all we have before discovered in the matter of the dimensions 
of curves. The reason of the advantage of this new calculus 
is, moreover, that it relieves the imagination in the problems, 
which Descartes excluded from his geometry under the pre- 
text that they most frequently lead to mechanics, but at 
bottom because they did not agree with his calculus. As 
for errors arising from ambiguous terms, it is our business 
to avoid them. 

Ph. There is also a case in which reasoning cannot be 
applied, but in which also there is no need of it and in which 
sight is worth more than reasoning. It is in intuitive knowl- 
edge, where the connection of ideas and truths is immediately 
seen. Such is the knowledge of indubitable maxims, and I am 
tempted to believe that this is the degree of evidence which 
the angels have at present, and which the spirits of just men 
made perfect will have in a future state regarding a thousand 
things which now escape our knowledge. § 15. But demon- 
stration, based upon mediate ideas, gives a reasoned knowledge. 
This is because the connection of the mediate idea with the 
extremes is necessary and is seen by & juxtaposition of evidence, 
similar to that of a yard-stick applied now to one cloth and now 
to another to show that they are equal. § 16. But if the con- 
nection is only probable, the judgment gives only an opinion. 

Th. God alone has the advantage of having only intuitive 
knowledge. But very happy souls, however detached they are 
from these material bodies, and the genii themselves, however 
exalted they are, although they have a knowledge without com- 
parison more intuitive than ours, and often see at a glance what 
we discover only by the force of consequences after having em- 
ployed time and labor, must likewise find difficulties in their path 
without which they would not have the pleasure of making dis- 
coveries, which pleasure is one of the greatest. And we must 
always admit that there will be an infinite ■ number of truths 
concealed from them either wholly or for a time, whereto they 
must attain by force of consequences and by demonstration or 
even frequently by conjecture. 

Ph. [These genii then are only animals more perfect than 
we ; it is just as if you said with the emperor of the moon : it 
is all as here.~] 



ch. xvi t] ON HUMAN UNDERSTANDING 575 

Th. I will say so, not entirely, but in regard to the ground of 
things, for the modes and degrees of perfection vary infinitely. 
Meanwhile the ground is everywhere the same, a maxim which 
is fundamental with me and reigns in all my philosophy. I con- 
ceive things unknown or confusedly known only after the manner 
of those which are distinctly known to us ; a procedure which 
makes philosophy very easy, and I believe indeed that it must 
do so. But if this philosophy is simplest in its ground, it is 
also the richest in its modes, because nature may vary them 
infinitely, as indeed she has done with as much abundance, 
order, and ornateness as it is possible to imagine. This is the 
reason why I believe there is no genius however sublime who 
has not an infinite number of them above him. Yet although 
we are very inferior to so many intelligent beings, we have the 
advantage of not being visibly controlled upon this globe where 
we hold indisputably the first rank ; and with all the ignorance 
in which we are immersed we have always the pleasure of seeing 
nothing which surpasses us. And if we were vain we might 
judge as Caesar, who preferred to be first in a country town 
rather than second in Rome. For the rest, I speak here only 
of the natural knowledge of these spirits and not of the beatific 
vision, 1 or of the supernatural light that God is pleased to give 
them. 

1 The term "beatific vision" (visio beatifica) denotes in theological and 
religious thought the direct and immediate or intuitive vision of God enjoyed 
by the saints and angels in heaven and supposed to constitute their essential 
bliss. The philosophical significance of the idea as historically developed, 
with respect both to its speculative and practical uses, lies in the fact that the 
visio beatifica was regarded as the sole means of obtaining absolute truth and 
of realizing absolute blessedness. The idea thus involved more or less ex- 
plicitly a species of knowledge supernaturally mediated in some unknown and 
unexplained way, but considered, because of the method of its mediation, as 
far superior in certainty and completeness to any knowledge that finite beings 
could attain through the unaided action of their own intellectual powers — 
in brief, as the very perfection of knowledge attainable by such beings. 

The idea originated in Plato's conception of an immediate intuition, going 
beyond rational thought, of the pure forms of reality or the Ideas. Trans- 
formed by Philo and Plotinus into their ecstatic intuition, or that identifica- 
tion of the human with the Divine in which all consciousness of individual 
personality is lost ; combined by Clement and Origen, in view of certain ex- 
pressions in the Pauline epistles, with the thought of a personality in union 
with whom the self-consciousness of the individual is preserved; and still 
further developed by Augustine, as the principle of the absolute and imme- 
diate certainty of inner experience or consciousness involving within itself 
the idea of God as the absolute personality and the sum and essence of all 



576 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

§ 19. Ph. As each one makes use of reasoning either with 
regard to himself or with reference to another, it will not be 
useless to make some reflections upon four sorts of arguments 
which men are wont to use in order to draw others to their 
opinions or at least so to keep them in awe as to prevent them 
from contradicting. The first argument may be called argu- 
mentum ad vercundiam, when we cite the opinion of those 
who have acquired authority by their knowledge, rank, power, 
or otherwise ; for when another does not yield to it promptly, 
he is liable to be censured as full of vanity and even to be 
charged with insolence. § 20. There is also 2) argumentum 
ad ignorantiam, i. e. to demand that the opponent admit the 
proof or assign a better. § 21. There is 3) argumentum ad 
hominem, when we press a man by what he has himself said. 
§ 22. Finally, there is 4) argumentum ad judicium, which con- 
sists in employing proofs drawn from some one of the sources 
of knowledge or probability. This is the only one of all which 
advances and instructs us ; for if from respect I dare not con- 
tradict, or if I have nothing better to say, or if I contradict 
myself, it does not follow that you are right. I may be modest, 
ignorant, deceived, and you prove yourself to be mistaken also. 

Th. It is doubtless necessary to make a difference between 
what is proper to be said and what is truly to be believed. Yet 
as the majority of truths may be boldly maintained, there is 
some prejudice against an opinion that it is necessary to con- 
ceal. The argument ad ignorantiam is valid in cases of pre- 
sumption where it is reasonable to hold to an opinion till the 
contrary is proved. The argument ad hominem has this effect, 
that it shows that one or the other assertion is false and that 

truth, this conception passed into the philosophical and religious thinking 
and life of the Christian Church, and became especially prominent in the 
teachings of the Mediaeval Mystics. On this historical development cf. Win- 
delhand, Hist, of Philos., trans, by Tufts, pp. 119 sq., 227 sq., 249 sq., 276 sq.; 
Zeller, Philos. d. Griech., III., 2 [Vol. 6], 413 sq., 611 sq., 854, note 4, 3d ed., 
18S1 ; Benn, Greek Philosophers, 2, 311 sq. 

In a modified form this intuition of divine things became what the Church 
fathers and the theological and philosophical writers of the Middle Age termed 
the lumen gratise, " the light of grace," the supernatural light given through 
divine inspiration,. in opposition to the lumen naturale or " natural light," the 
rational knowledge given by nature to all men as such. Cf. Neiv Essays, 
Bk. I., chap. 1, § 21, Th., ante, p. 71; Gerhardt, Leibniz, philos. Schrifl., 6, 
494 sq., 503 sq.; Hamilton's Reid, Note A, § V., IV.. 1, note t, Vol. 2, p. 763, 
§ VI., 20-22, 25-26, pp. 776-778, 54, p. 785, 8th ed., 1880. - Tr. 



en. xvn] ON HUMAN UNDERSTANDING 577 

the opponent is deceived whatever way he takes it. We might 
bring yet other arguments which are used, for example the 
one we might call ad vertiginem, when we reason thus : if this 
proof is not received we have no means of attaining certainty 
upon the point in question, which we take as an absurdity. 
This argument is valid in certain cases, as if any one wished 
to deny primitive and immediate truths, for example, that any- 
thing can be and not be at the same time, or that we ourselves 
exist, for if he were right there would be no means of knowing 
anything whatever. But when certain principles are produced 
and we wish to maintain them because otherwise the entire 
system of some received doctrine would fall, the argument is 
not decisive ; for we must distinguish between what is neces- 
sary to maintain our knowledge and between what serves as a 
foundation for our received doctrines or practices. Use was 
sometimes made among jurisconsults of probable reasoning in 
order to justify the condemnation or torture of pretended sor- 
cerers upon the deposition of others accused of the same crime, 
for it was said : if this argument falls, how shall we convict 
them? And sometimes in a criminal case certain authors 
maintain that in the facts where conviction is more difficult, 
more slender proofs may pass as sufficient. But this is not a 
reason. It proves only that we must employ more care, and 
not that we must believe more thoughtlessly, except in the 
case of extremely dangerous crimes, as, for example, in the 
matter of high treason, where this consideration has weight, 
not to condemn a man, but to prevent him from doing harm ; 
so that there may be a mean, not between guilty and not guilty, 
but between condemnation and banishment in the judgments, 
where law and custom admit it. Use has been made of a similar 
argument in Germany for some time in order to give color to 
the coining of bad moneys for (they say) if we must keep to 
the prescribed rules, we cannot coin it without loss. We must 
be allowed then to debase its alloy. But besides the fact that 
we must diminish the weight only and not the alloy or super- 
scription the better to obviate frauds, we suppose a practice 
necessary which is not so ; for no command of heaven nor any 
human law exists obliging those who have no mine nor occa- 
sion to have silver in bars to coin money ; and to make money 
out of money is a bad practice which naturally carries deterio- 
2 p 



578 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

ration with it. But how (they say) shall we exercise our 
regale in coining it ? The reply is easy. Content yourselves 
with coining a little from good silver, even at a small loss, if 
you think its coinage a matter of importance to yourselves, 
since you have no need nor right to flood the world with 
debased small coin. 

§ 23. Ph. After having said a word concerning the relation 
of our reason to other men, let us add something about its 
relation to God, which makes us distinguish between what is 
contrary to reason and what is above reason. Of the first class 
is everything which is incompatible with our clear and dis- 
tinct ideas ; of the second is every thought whose truth or 
probability evidently cannot be deduced from sensation or 
reflection by the aid of reason. 1 Thus the existence of more 
than one God is contrary to reason, and the resurrection of the 
dead is above reason. 

Tli. I find something to say regarding your definition of 
that which is above reason, at least if you connect it with the 
received use of this phrase ; for it seems to me that from the 
manner in which this definition is couched, it goes too far in 
one direction and not far enough in the other ; and if we fol- 
low it, all that of which we are ignorant and which in our 
present condition we are unable to know, would be above 
reason, for example, that a given fixed star is greater or 
less than the sun ; again, that Vesuvius will send out fire in 
such a year ; these are facts the knowledge of which is beyond 
us, not because they are above reason, but because they are 
beyond our senses ; for we could very well judge of them, if 
we had more perfect organs or more. information about the 
circumstances. There are also difficulties which are beyond 
our present faculty, but not beyond reason as a whole ; for 
example, there is no astronomer hsre below who can calculate 
the detail of an eclipse in the space of a pater and without 
taking the pen in hand, yet there are perhaps genii to whom 
that would be mere play. Thus all things might be made 
known or practicable by the aid of reason, by supposing more 
information concerning the facts, more perfect organs, and a 
more elevated mind. 

i Of. Locke, Exam, of Malebranche, § 53, Philos. Wks., Vol. 2, p. 455 (Bohn's 
ed.). — Tr. 



ch. xvii] ON HUMAN UNDERSTANDING 579 

Ph. This objection ceases if I understand my definition not 
only of our sensation or reflection, but also of that of every 
other possible created spirit. 

Th. If you take it so, you are right. But the other diffi- 
culty remains, viz. : that there will be nothing above reason 
according to our definition, because God will always be able 
to give the means of apprehending by sensation and reflection 
any truth whatever ; as in reality the greatest mysteries be- 
come known to us by the testimony of God which we recognize 
by the motives of credibility, upon which our religion is based. 
And these motives undoubtedly depend upon sensation and 
reflection. The question then seems to be not whether the 
existence of a fact or the truth of a proposition can be deduced 
from the principles which reason uses, i.e. from sensation and 
reflection, or rather the external and internal sense, but whether 
a created spirit is capable of knowing the how of this fact, or 
the a priori reason of this truth; so that we may say that 
what is beyond reason may indeed be apprehended, but it can- 
not be comprehended by the means and forces of created reason, 
however great and exalted it be. It is reserved to God alone 
to understand it, as it belongs to him alone to assert it. 1 

Ph. This consideration appears to me a good one, and it is 

1 Of. Theodice'e, Discours prelim., especially §§ 2, 5, 23, 56; New Essays, 
Preface, ante, pp. 55, 60 ; Annotatiunculse subitanse ad Tolandi Ubrum, De 
christianismo mysteriis carente, 1701, Dutens, Leibnit. op. om., 5, 142, 143; 
Pichler, Theol. d. Leibniz, 1, 208-225; K. Fischer, Gesch. d. n. Philos., Bd. II., 
Leibniz, 3d ed., pp. 541-547. 

According to Leibnitz, reason and faith are not absolutely opposed. Reason 
must be capable of apprehending the supernatural as fact, even though in its 
present stage of development — and perhaps in all its development — it may 
never be able to comprehend it exhaustively. The supernatural, while it may 
be outside of and beyond any present or future possible finite experience, is 
not then contrary to reason. In fact, to be apprehended or accepted as fact 
at all, it must present such intrinsic rationality as is sufficient to induce be- 
lief, i.e. it must show itself to be intrinsically possible and not contrary to 
any well-established knowledge. In this sense it is not wholly above reason, — 
if it were, it would not at all concern us, — and may therefore become a part 
of the sum-total of our knowledge. The contention of both Leibnitz and 
Locke is, in fact, that the opposition is not between reason and faith, but 
rather between reason and unfounded authority. Leibnitz rejects entirely 
both belief based on blind submission to mere authority, and that ultra- 
rationalism which refuses to admit the existence of anything not coming 
entirely within the range of experience, particularly that experience which 
is sensuous and individual and excludes that which is spiritual and uni- 
versal. — Tr. 



580 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

thus that I wish my definition to be understood. This same 
consideration confirms me also in my present opinion that the 
manner of speaking which opposes reason to faith, although it 
has weighty authority, is improper ; for it is by reason that 
we verify what we must believe. 1 Faith is a firm assent, and 
assent, regulated as it should be, can only be given upon good 
reasons. Thus he who believes without any reason for be- 
lieving may be in love with his fancies, but it is not true that 
he seeks the truth, nor that he renders lawful obedience to his 
divine Master, who would have him make use of the faculties 
with which he has enriched him in order to preserve him from 
error. Otherwise if he is in the good way, it is by chance ; 
and if in the bad, it is by his fault, for which he is accountable 
to God. 

Tli. I commend you strongly, sir, when you wish faith to 
be grounded in reason: without this why should we prefer 
the Bible to the Koran or to the ancient books of the Brahmins ? 
Our theologians also and other learned men have clearly recog- 
nized it, and it is this which has caused us to have such fine 
works concerning the truth of the Christian religion, and so 
many excellent proofs as have been put forward against the 
heathen and other unbelievers, ancient and modern. Wise 
persons also have always regarded as suspicious those who 
have maintained that it was not necessary to trouble them- 
selves about reasons and proofs when it was a question of 
belief; an impossibility in fact unless to believe signifies to 
recite or repeat or to let pass without troubling themselves, as 
many people do, and as indeed is the character of some nations 
more than others. This is the reason why, when some Aristo- 
telian philosophers of the fifteenth or sixteenth century, whose 
remains were still extant a long time after (as we may judge 
by the letters of the late Mr. Kaude 2 and the Naudeana), 

1 Gerhardt reads: "car c'est par la raison que nous verifions ce que nous 
devons croire." Erdmann, Jacques, and Janet read: " car c'est par la raison 
que nous devons croire." — Tr. 

2 Gabriel Naude', 1600-1653, a celebrated French scholar, bibliographer and 
librarian, who at first studied medicine and was physician to Louis XIII, but 
who afterwards devoted himself entirely to literary and library work. He 
was the creator of the celebrated Bibliotheque Mazarine. His Naudeana, a 
collection of anecdotes drawn from his conversations, appeared at Paris, 1701. 
— Tr. 



ch. xvii] ON HUMAN UNDERSTANDING 581 

desired, to maintain two opposite truths, one philosophical, the 
other theological, the last Lateran Council under Leo X was 
right in opposing them, as I think I have already remarked. 1 
And a dispute wholly similar was raised at Helmstadt in 
former times between Daniel Hofmann, a theologian, and 
Corneille Martin, a philosopher, but with this difference, that 
the philosopher reconciled philosophy to revelation and the 
theologian wished to decline its use. But the Duke Julius, 



1 Cf. The'odice'e, Discours prelim., §§7, 8, 11. The "Aristotelian philoso- 
phers " here referred to, were divided into two schools, the Alexandrists and 
the Averroists, according as they followed the interpretation of Aristotle 
given by Alexander of Aphrodisias, c. 200, or Averroes, 1126-1198. Both 
schools denied the immortality of the individual soul ; the Averroists ground- 
ing their denial on, and finding a compensation for such immortality in, the 
unity of the intellect — the rationally active part of the soul (voOs) — in all 
men ; while the Alexandrists regarded individual souls, including this rational 
part, as naturally mortal. 

' J Both schools were opposed and condemned by the Church, and the theory 
of " the double truth " (philosophical truth having its source in natural reason, 
theological in a supernatural revelation), held by both schools as a shield to 
protect them, in the exposition and dissemination of their views, from the 
interference and persecution of the Church, was adjudged heretical in the 
decree " Apostolic! Regiminis " of the fifth Lateran Council of December 19, 
1512, under Leo X. This theory in the case of many of its advocates was, no 
doubt, the natural and "honest expression of the inner discord " resulting 
from the opposition of the two then prevalent authorities, Greek philosophy 
and religious tradition. 

Chief among those who advocated this theory of "the twofold truth" 
was Pietro Pomponazzi, 1462-1525, an Italian physician and philosopher, in 
his time one of the most sagacious and subtle interpreters of Aristotle of the 
Alexandrian school. He maintained, in his Tractatus de immortalitate animi, 
Bologna, 151(3, 8vo, that none of the reasons assigned for the dogma of immor- 
tality were categorically demonstrative, and that therefore the doctrine must 
depend upon revelation. When accused of heresy, he stoutly asserted his in- 
nocence, saying that he taught nothing contrary to the belief of the Church, 
but simply expounded Aristotle, and adding that he denied as a Christian 
what he affirmed as a philosopher. He attempted to discover a deeper foun- 
dation for the theory of "the twofold truth,'' through the recognition of the 
twofold nature of reason, the speculative and the practical, the former 
furnishing the basis of philosophy, the latter that of theology and ethics. 

On the whole subject, cf. M. Maywald, Die Lehre v. d. zweifachen Wahr- 
heit, Berlin, 1871; Windelband, Hist, of Philos., trans, by Tufts, pp. 318 sq., 
339 sq., 359; Piinjer, Gesch. d. christ. Religionsphilos., 1, 28-29, 37, Eng. trans., 
1, 39 sq., 50-52; Stockl, Gesch. d. Philos. d. Mittelalters, III [Vol. 4], 202-207, 
and for an account of Pomponazzi and his philosophy, ibid. 213-244 ; cf. also 
L. Ferri, La Psicologia di P. Pomponazzi, Rome, 1877. For the decree 
"Apostolici Regiminis," cf. Acta Concil. Reg., Vol. 34, p. 333, Paris, 1644, 
37 vols., fol. ; Labbe', Concil., torn. 19, col. 842; Stockl, op. cit. ,111 [Vol.4], 
206, n. 1. — Tr. 



582 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

founder of the university, decided for the philosopher. 1 It is 
true that in our time a person of the most exalted position 
said that in a matter of faith he must put out his eyes in order 
to see clearly, and Tertullian says somewhere : this is true, 
because it is impossible : 2 it must be believed, for it is an 
absurdity. But if the intention of those who explain them- 
selves in this way is good, these expressions are always ex- 
aggerated and may do harm. St. Paul speaks more justly 
when he says that the wisdom of God is foolishness with 
men; because men judge of things only according to their 
experience, which is extremely limited, and everything not 
agreeing therewith appears to them an absurdity. But this 
judgment is very rash, for there is indeed an infinite number 
of natural things which would pass with us as absurd, if they 
were told us, as the ice which was said to cover our rivers 
appeared to the king of Siam. But the order of nature itself 
not being of any metaphysical necessity, is grounded only in 
the good pleasure of God, so that he may deviate therefrom 
by the superior reasons of grace, 3 although he must proceed 
therein only upon good proofs which can come only from the 
testimony of God himself, to which we must defer absolutely 
when it is duly verified. 

1 Cf. Theodicee, Discours prelim. § 13. On the controversy itself, extend- 
ing from 1598-1601, cf. Piinjer, Gesch. d. Christ. Religionsphilosophie, 1, 132- 
141, Eng. trans., 1, 178-190. For the fullest accounts, cf. G. Thomasius, Be 
Gontroversia Hofmanniana, Erlangen, 1841, and E. Schlee (who gives the 
external history with complete references to the literature) , Ber Streit d. Dan. 
Hofmann u. d. Verhaltniss d. Philos. z. Theol., Marburg, 1862. Schaarschmidt 
refers to E. L. Th. Henke, Georg Calixtits n. seine Zeit, Einleitung, p. 73 sq., 
and says that Duke Julius [Henry Julius, son of the founder of the Uni- 
versity, and the successor of his father in the government in 1589] , who had 
examined the documents in the controversy and reached a decision, did rightly 
in protecting the philosopher against his opponents, who spread abroad the 
most horrible calumnies concerning him, and treated him in general very 
harshly. — Tr. 

2 Cf. Tertullian, Be Came Christi, chap. 5: " Mortuus est dei Alius; prorsus 
credibile est, quia ineptum est. Et sepultus resurrexit ; certum est, quia im- 
possibile est." Leibnitz also refers to tbis passage in the Theodicee, Discours 
pre'lim. § 50. — Tr. 

3 Cf. ante, p. 462, note 1. — Tr. 



en. xvm] ON HUMAN UNDERSTANDING 583 

CHAPTER XVIII 

OF FAITH AND REASON AND THEIR DISTINCT LIMITS 

§ 1. Ph. Let us accommodate ourselves meanwhile to the 
received mode of speech, and suffer faith to be distinguished in 
a certain sense from reason. It is proper that this sense be very 
accurately explained and the limits existing between these two 
things be established ; for uncertainty regarding these limits 
has certainly produced in the world great disputes and perhaps 
caused even great disorders. It is at least manifest that, until 
these have been determined, it is in vain for us to discuss, since 
we must employ reason in discussing faith. § 2. I find that 
each sect uses reason with pleasure so long as it believes it 
can derive therefrom any aid : but as soon as reason fails, they 
cry out : it is an article of faith, which is above reason. But 
the opponent could make use of the same evasion if any one 
took it upon himself to argue against him, unless we indicate 
why that would not be permitted him in a case seemingly 
parallel. I suppose that reason is here the discovery of the 
certitude or probability of propositions drawn from knowledge 
which we have acquired by the use of our natural faculties, 
that is to say by sensation and by reflection ; and that faith is 
the assent given to a proposition based upon revelation, that is 
to say upon an extraordinary communication from God which 
has made it known to man. § 3. But a man inspired of God 
cannot communicate to others any new simple idea, because he 
uses only words or other signs which awake in us the simple 
ideas that custom has attached to them or their combination ; 
and whatever new ideas St. Paul received when he was carried 
up to the third heaven, all that he could say was : they are 
things eye hath not seen, ear hath not heard, and ivhich have 
never entered into the heart of man. 1 Suppose there were creat- 
ures in the planet Jupiter provided with six senses and that 
God in a supernatural way gave to a man among us the ideas of 
this sixth sense, he could not by means of words make them 

1 1 Cor. 2, 9. — Tk. 



584 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

spring up in the minds of other men. 1 We must then distin- 
guish between original and traditional revelation. The first is 
an impression which God makes immediately upon the mind, 
and to this we can fix no limits ; the other comes only by the 
ordinary means of communication and cannot give new simple 
ideas. § 4. It is true, however, that the truths which may be 
discovered by reason can be communicated to us by a tradi- 
tional revelation, as if God had desired to communicate to men 
geometrical theorems, but this would never amount to so great 
a certainty as if we had their demonstration drawn from the 
connection of ideas. It is also as if Noah had a more certain 
knowledge of the deluge than that which we have acquired 
from the book of Moses and as if the assurance of one wdio has 
seen that Moses actually wrote it and that he did the miracles 
which justify his inspiration was greater than ours. § 5. This 
it is which makes it impossible for revelation to go against the 
clear evidence of reason, because whenever the revelation is 
immediate and original we must know with certainty that we 
are not deceived in attributing it to God and that we compre- 
hend its meaning ; and this evidence can never be greater than 
that of our intuitive knowledge ; and consequently no proposi- 
tion can be received as divine revelation when it is contradic- 
torily opposed to this immediate knowledge. Otherwise there 
would no longer remain any difference in the world between 
truth and falsehood, any measure of the credible and incredi- 
ble. And it is inconceivable that a thing comes from God, this 
beneficent author of our being, which received as true must 
overturn the foundations of our knowledge and render all our 
faculties useless. § 6. Those who have revelation only medi- 
ately, or by tradition from mouth to mouth or by writing, have 
again more need of reason to assure themselves of it. § 7. 
Meanwhile it is always true that the things which are beyond 
what our faculties can discover are the proper matters of faith, 

1 Of. Lessing's amplification of a similar thought, perhaps suggested by this 
passage of Leibnitz, in his Fragment: Dass mehr als fiinf Sinne fur den 
Menschen sein Mnnen, Sammt. Schrift, ed. Lachmann-Maltzahn, Leipzig, 
1853-1857, Vol. 11, Pt. 2, p. 458. On the relation of Lessing to Leibnitz, c/. 
Zimmermann, Leibniz unci Lessing, JEine Studie, Wien, 1855; Piinjer, Gesch. 
d. christ. Religionsphilosophie, 1, 421-425, Eng. trans., 1, 566-570; Pfleiderer, 
Religionsphilosophie, 1, 143, Eng. trans., 1, 145-146; K. Fischer, Gesch. d. n. 
Philos., Bd. II., Leibniz, 3d ed., pp. 617-619. — Tk. 



ch. xvin] ON HUMAN UNDERSTANDING 585 

as the fall of the rebellious angels, the resurrection of the 
dead. § 9. Here we must listen solely to revelation. And 
even as regards probable propositions an evident revelation 
will determine us against the probability. 

Th. If you take faith as that which is grounded in the 
motives of credibility (as they are called) and detach it from 
the internal grace which immediately determines the mind, 
all that you say, sir, is beyond dispute. It must be admitted 
that there are many judgments more evident than those de- 
pending upon these motives. Some are urged on by them far- 
ther than others, and there are indeed many persons who have 
never known them and still less considered them and who con- 
sequently have not even that which might pass as a motive of 
probability. But the internal grace of the Holy Spirit imme- 
diately supplies it in a supernatural way, and this it is which 
produces what the theologians properly call a divine faith. 
It is true that God never gives it except when the belief it 
produces is founded in reason; otherwise he would destroy 
the means of knowing the truth and open the door to enthu- 
siasm ; but it is not necessary for all who have this divine 
faith to know these reasons and still less to have them always 
before their eyes. Otherwise simple-minded people and idiots, 
to-day at least, would never have the true faith, and the most 
enlightened would not have it when they were most in need 
of it, for they cannot always remember the reasons for their 
belief. The question of the use of reason in theology has 
been one of the questions most discussed, both between the 
Socinians and those who may be called Catholics in a general 
sense, and between the Reformers and the Evangelicals, as 
those are named by way of preference in Germany whom many 
inaptly call Lutherans. I remember to have read once a Meta- 
physic of one Stegmann, 1 a Socinian (a different man from 
Joshua Stegmann, 2 who himself wrote against them), which so 

1 Cf. Theodicee, Discours prelim., § 16, where Leibnitz refers to him as 
Christopher Stegmann, a Socinian. He was the youngest brother of Joachim 
Stegmann, also a Socinian and author of many works on mathematics and 
theology, who died in exile at Clausenburg in Siebenbiirgen in 1632. Christo- 
pher wrote a work entitled Dyas philosophica, which is, perhaps, the " Meta- 
physic" of which Leibnitz here speaks. For further account of him, cf. 
Jocher, Allgemeines Gelehrten-Lexicon, Pt. IV., 794, Leipzig, 1750. — Tr. 

2 Joshua Stegmann, 1588-1632, a Lutheran divine, was Professor at Leipzig, 
Wittenberg, and Rinteln, and the author of many theological works, and of 



586 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

far as I know has not yet been printed ; on the other hand, one 
Kessler, 1 a theologian of Saxony, has written a Logic and some 
other philosophical treatises expressly opposed to the Socinians. 
We may say in general, that the Socinians are too qnick to 
reject everything which is not conformed to the order of 
nature, even when they cannot prove absolutely its impossi- 
bility. But their opponents also sometimes go too far and 
push mystery to the verge of contradiction ; in which they 
injure the truth they try to defend. ^ I was surprised to see 
once in the " Summa Theologise " of Father Honore Fabry, 2 
who otherwise was one of the most clever of his order, which 
he denied in divine things (as do also some other theologians), 
this great principle which states that things which are identical 
with a third thing are identical with each other. This is to give 

the famous German hymn, " Ach, bleih' mit deiner Gnade" (Eng. trans, in 
Lyra Germanica, 2, 120, "Abide among us with thy grace, Lord Jesus, ever- 
more"). He was opposed to the Socinians or Photinians, and wrote against 
them his Photinianismus, h. e. Succincta Refutatio Errorum Photinianorum, 
quinquaginta sex disputationibus breviter comprehensa, Rinteln, 1623, 8vo; 
Frankfort, 1643. Leibnitz mentions him again in the Theodicee, Discours 
prelim., § 62. For further account of him, cf. Winer, Handbxich d. theolog. 
Lit., 1, 354; 2, 748; Jocher, Allgemeines Gelehrten-Lexicon, Pt. IV., 794, 
Leipzig, 1750. — Tr. 

1 Andreas Kessler, 1595-1643, a Lutheran divine, studied at Jena and 
Wittenberg, and was pastor at Eisfeld, Eisenach, and Coburg, where he died 
in consequence of a stroke of apoplexy received while preaching. He wrote 
against the Socinians or Photinians his Physicm Photlnianx examen, Eisfeld, 
1628, Wittenberg, 1656, 8vo ; Metaphysicx Photinianse examen, 3d ed., Witten- 
berg, 1648, 8vo ; Logicse Photlnianx examen, 2d ed., Wittenberg, 1624, 4to, new 
ed. 1642, 8vo. His writings exhibit a good deal of method and exactness. 
Leibnitz also refers to him in the Theodicee, Discours prelini., § 16. For fur- 
ther account of him, cf. Jocher, Allgemeines Gelehrten-Lexicon, Pt. II., 2072, 
Leipzig, 1750. — Tr. 

2 Honore Fabri, 1607-1688, a French mathematician and philosopher, and 
a Jesuit, who taught philosophy and mathematics in the college of his order 
at Lyons, and later became Grand-Penitentiary at the holy office in Rome. 
Among his writings are, Synopsis geometrica, Lugd., 1669; Physica sen sci- 
entia rejourn corporearum in decern tractatus distributa, Lugd., 1669 ; Summula 
Theologix, Lyons, 1669. Leibnitz regarded him as one of the most distin- 
guished men of his time, and frequently mentioned him with praise. Cf. 
Theodicee, Pt. III., § 348; Hypoth. phys. nova, §§ 56, 59, Gerhardt, Leibniz. 

philos. Schrift., 4, 208, 214, 216; Theoria motus abstracti, prope fin., ibid., 
240, and Appendix thereto, containing a letter of Fabri to Leibnitz, ibid., 241- 
244, and of Leibnitz to Fabri, ibid., 244-261 (also Gerhardt, Leibniz, math. 
Schrift., II., 2 [Vol. 6], 81-98). For another Appendix to a letter of Leibnitz 
to Fabri, cf. Gerhardt, Leibniz, math. Schrift., II., 2 [Vol. 6], 98-106, trans. 
infra, Appendix, pp. 699 sq. — Tr. 



ch. xviii] ON HUMAN UNDERSTANDING 587 

a gained case to the opponent without thinking and to deprive 
all reasoning of certainty. <^We must say rather that this 
principle is badly applied. The same author rejects in his 
philosophy the virtual distinctions, which the Scotists put 
into created things, because they reversed, he says, the prin- 
ciple of contradiction : and when the objection is made to him 
that these distinctions must be admitted in God, he replies 
that faith orders it. But how can faith order that, whatever 
it be, which reverses a principle without which all belief, 
affirmation, or negation would be vain ? Two propositions true 
at the same time must therefore necessarily not be wholly 
contradictory ; and if A and C are not the same thing, it is 
clearly necessary that B which is identical with A be taken 
otherwise than B which is identical with C. JSTicolaus 
Vedelius, 1 a professor at Geneva and afterward at Deventer, 
once published a book entitled "Rationale Theologicum," to 
which Jean Musteus, 2 a professor at Jena (which is an Evan- 

1 Cf. Theodice'e, Discours prelim., §§ 20, 67. Nicolas Vedel, a German 
Reformed (Calvinistic) divine, was Professor of Philosophy and minister at 
Geneva, of Theology and Hebrew at Deventer, 1630-1638, and of Theology 
at Franeker from 1638 till his death in 1642. He was a great adversary of 
the Arminians, and wrote against them his De Arcanis Arminianismi, 
Leyden, 1632-1634. His Rationale theologicum, seu de necessitate et vero usu 
principiorum rationis ac philosophise in controversiis theologicis, lib. tres, 
Geneva, 1628, was attacked by Barth. Nihus, 1584-1657, in his Morosophus 
sea Vedelius in sua rationali prorsus irrationalis, Cologne, 1646, as well as 
by Musseus. On the controversy between Vedelius and Musseus, cf. Piinjer, 
Gesch. d. christ. Religionsphilosophie, 1, 118-124, Eng. trans., 159-167. For 
further account of Vedel, cf. Winer, Handbuch d. theol. Lit., 1, 353, 375, 565; 
J. P. Niceron, Mem. d'hommes, Vol. 33, 1736. — Tr. 

2 Cf. The'odice'e, Discours prelim., §§ 20, 67. Johannes Musams, 1613-1681, 
a Lutheran divine, was Professor of History, 1642-1646, and of Theology, 1646 
till his death, at Jena. He was the greatest Lutheran divine of his century 
after J. Gerhard, 1582-1637, and Geo. Calixtus, 1586-1656. He distinguished 
between theology and the confessions and favored liberty of scientific and 
theological researches. He was everywhere acknowledged as a very learned 
man, and his writings are distinguished by philosophical acumen so that he 
was accused of "magis philosophari quam quod loquatur eloquia Dei." He 
wrote in defence of Christianity against Herbert of Cherhury, 1581-1648, a 
work entitled Be luminis natures et ei innixse theologize naturalis insufficientia 
ad salutem, Jena, 1667; against Spiuoza, his Tractatus theolog.-polit., etc., 
Jena, 1674 (on Muspeus and Spinoza, cf. Piinjer, Gesch. d. christ. Religions- 
philos., 1, 322-323, Eng. trans., 1, 435). His De usu principiorum rationis et 
philosophise in controversiis theologicis lib. tres Nic. Veclelii Rationali Theo- 
logico potissimum oppositi appeared at Jena, 1644; 2d ed., 1665. For further 
account of Musseus, cf. Herzog, Realencyklopadie, 2d ed., 10, 376-380. — Tb. 



588 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

gelical university in Thuringia), wrote another book in oppo- 
sition upon the same subject, i.e. upon "The Use of Reason in 
Theology." I remember to have considered these formerly, 
and to have remarked that the principal controversy was ob- 
scured by incidental questions, as when it is asked, what a 
theological conclusion is, and whether it is necessary to judge 
of it by the terms which compose it, or by the means which 
prove it, and consequently whether Occam : was right or not in 
saying that the knowledge of one and the same conclusion, is 
the same whatever 2 the means employed to prove it ; and he 
delays upon a multitude of other minutiae of still less import- 
ance, which concern only terms. ^Meanwhile Musaeus agreed 
with him that the principles of reason necessary by a logical 
necessity, i.e. the opposite of which implies a contradiction, 
must and may be employed safely in theology; but he had 
reason to deny that what is only necessary by a physical neces- 
sity (i.e. founded upon induction from that which is customary 
in nature, or upon natural laws which, so to speak, are of divine 
institution) is sufficient to refute the belief in a mystery or 
miracle, since it depends upon God to change the ordinary 
course of things. Thus it is according to the order of nature 
that we may be certain that one and the same person cannot 
be at the same time a mother and a virgin, or that a human 
body cannot fail to be obvious to the senses, although the 
contrary of both may be possible to God. Veclelius also 
appears to agree to this distinction. But we sometimes dis- 

1 William of Occam, the date of whose birth is unknown, and who died at 
Munich in 1347, renewed and developed Nominalism in the form of Termi- 
nism, the Termini (concepts) being subjective signs of really existing things, 
and not mere names — -flatus vocis — as so frequently regarded. The relations 
of his philosophy to subsequent thinking are well set forth by Windelband- 
Tufts, Hist, of Philos., pp. 312, 315, 325 sq., 342 sq. For Leibnitz's view of 
his Nominalism, cf. Be stilo philos. Nizolii, § 28, Erdrnann, 68 b-69 b; Ger- 
hardt, 4, 157-158. On his life and philosophy, cf. Stockl, Gesch. d. Philos. a. 
Mittelalters, II., 2 [Vol. 3], 986-1021; Haure'au, Hist. d. la Philos. scolastique, 
II., 2 [Vol. 3], 356-430; Prantl, Gesch. d. LogiTc, 3, 327-420. — Tr. 

2 Gerhardt reads: " quel moyen qu'on employe," etc. ; Erdmann, Jacques, 
and Janet read: "que le moyen qu'on emploie," etc., i.e. "as the means 
employed," etc. Schaarschmidt, in his translation, follows the reading of 
Erdmann, Jacques, and Janet, and says in his note to the passage : "Dass wir 
mit andern Worten bei unserm Schlussverfahren uns nothwendig im Cirkel 
bewegten," i.e. " That we, in other words, in our reasoning, necessarily moved 
in a circle." The correct reading can be determined only by the exact lan- 
guage of Occam, which thus far I have been unable to find. — Tr. 



ch. xvin] ON HUMAN UNDERSTANDING 589 

pute about certain principles, whether they are logically- 
necessary, or only physically so.^Such is the dispute with 
the Socinians, whether substance can be multiplied when the 
individual essence does not exist; and the dispute with the 
Zwinglians, whether a body can be only in one place. JSTow 
we must admit that every time that logical necessity is not 
demonstrated, we can presume in a proposition only physical 
necessity. But it seems to me that a question remains, which 
the authors of whom I have just spoken have not sufficiently 
examined, namely this : Suppose that on one side we find the 
literal sense of a text of Holy Scripture, and on the other a 
great appearance of logical impossibility, or at least an ad- 
mitted physical impossibility, is it more reasonable to deny the 
literal sense or the philosophical principle ? It is certain that 
there are passages where to abandon the letter occasions no 
difficulty, as when Scripture gives hands to God and attributes 
to him anger, penitence, and other human affections ; other- 
wise it would be necessary to array ourselves on the side of 
the anthropomorphists, or of certain English fanatics who 
believe that Herod was really changed into a fox when 
Jesus Christ called him by that name. It is here that the 
rules of interpretation are in place, and if they furnish nothing 
which combats the literal sense in order to favor the philo- 
sophic maxim, and if in addition the literal sense has nothing 
which attributes to God any imperfection, or entails any 
danger in the practice of piety, it is safer and indeed more 
reasonable to follow it. /These two authors whom I have just 
named dispute further upon the undertaking of Keckermann, 1 

1 Bartholemew Keckermann, 1573-1609, a Senii-Ramist, was Professor of 
Hebrew at Heidelberg, and, from 1601, of Philosophy at the Gymnasium at 
Dantzic. He was the author of many compilations, made for the use of his 
pupils in the gymnasium, in which he presented all the sciences in a method- 
ical and systematic form. His Opera omnia appeared at Geneva, 1614, 2 
vols., fol. Leibnitz refers to him in the same connection in the Theodicee, 
Discours prelim., § 59. For further account of him, cf. W. Gass, Gesch. d. 
protestantischen Dogmatik in ihrem Zusammenhange mil d. Theologie, Vol. 1, 
pp. 408 sq. Piinjer, Gesch. d. christ. Religionsphilos., 1, 118, 127, 128, Eng. 
trans., 1, 158, 170, 172, briefly refers to him. 

According to Schaarschmidt, Keckermann's proof of the Trinity from 
reason, which is quite closely connected with that of Lully, as Lully's with 
the thoughts of Augustine, is found in his Systema ss. theologies, (1st ed., 
1602; 2d ed., Hanovia?, 1607), chap. 3, pp. 20 sq., 3d ed., Hanovise, 1615. In 
the introduction Keckermann expresses himself very decidedly. " Fateor 



590 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

who wished to demonstrate the Trinity by reason, as Eaymond 
Lully 1 had also tried to do formerly. But Musseus acknowl- 
edged with sufficient fairness that if the demonstration of the 
Reformed author had been valid and just, he would have had 
nothing to say on the subject ; that he would have been right in 
maintaining as regards this article that the light of the Holy 
Spirit might be illumined by philosophy. They have also 
discussed the famous question, whether those who, without 
any knowledge of the revelation of the Old or New Testament, 
died in the opinions of a natural piety, could have been saved 
by this means and obtained the remission of their sins ? We 

equiclem ultro, circa mysterium de ss. Triade, ad id esse omnem intellectum 
humantim, quod est oculus vespertilionis ad solem," etc. Keckermann's de- 
monstration was refuted by Musseus in the " Dissertatio altera," appended to 
his De usu princip. rationis et philos. in controversiis theologicis, 2d ed., Jena?, 
1665. — Tk. 

1 Raymond Lully, 1234 or 1235-1315, best known as the inventor of the 
"Great Art," attempted to demonstrate against the assertions of the Aver- 
roists, the inherent rationality of the doctrines of Christianity. His Opera 
omnia, 10 vols. (Vols. 7 and 8 probably never printed), fol., appeared at 
Mainz, 1721-1742. For an account of his life and philosophy, cf. Stockl, 
Gesch. d. Philos. d. Mittelalters, II., 2 [Vol. 3], 924-952; Erdmann, Grund. d. 
Geseh. d. Philos., § 206, Vol. 1, pp. 375-393, Eug. trans., 1, 447-468; Neander, 
Hist, of the Christ. Relig. and Church, 4, 65-71, 426, 435 sq. ; for his Logic, 
cf. Prantl, Gesch. d. Logik im Abendlande, 3, 145-177. Cf. also an article 
by Delecluse in the " Revue de Deux Mondes," 1840. 

Lully occupied himself much with the proof of the Trinity, discussing it, 
according to Schaarschmidt, in his Qusestiones [Disputatio Erimitse et Ray- 
mwidi — Erdmann] super lib. Sententiarum, Lib. I., qusest. 6 ; Disputatio fidelis 
(catholici) et infidelis, pp. 2, 3; and especially in the Disputatio fidei et intel- 
lectus, Pt. I., where the question of the demonstrability of the Trinity is con- 
sidered in detail, and Pt. II., where the proof is attempted. Schaarschmidt 
thinks that Leibnitz probably has in mind this last work. All three works 
are found in Opera, Vol. 4, ed. Mainz, 1729. Stockl, op. cit., II., 2 [Vol 3], 942- 
944, gives an account of Lully 's argument on the Trinity, based chiefly on the 
Articuli fidei sacrosanctse, found in the collection of Lully 's works entitled 
Opera ea quss ad inventam a Lullo artem universalem pertinent, Argentorati, 
1598, 1607, and 1617, and also in Opera, Vol. 2, ed. Mainz, 1722. In his list of 
Lully's works, Stockl cites the following which discuss the Trinity : Liber con- 
tradictionis inter Raymundum et Averroistam de centum syllogismis circa 
mysterium Trinitatis; Liber de substantia et accidente in quo probatur 
Trinitas. Cf. also Neander, op. cit., 4, 465. 

For Leibnitz's own views on the Trinity, cf. his Defensio Trinitatis per 
nova reperta logica, contra Epistolam Ariani, Dutens, Leibnit. op. orn., 1, 10- 
16; Dugs Epist. ad Lmfierxun de Trinitate et Definitionibus Mathematicis 
circa Deum, Spiritus, etc., Dutens, op. cit., 1, 17-23; Remarqws sur le livre 
d'un Antitnnitaire Anglois, etc., Dutens, op. cit., 1, 24-27, and Feller, Leibnit. 
Miscellanea, No. IV., pp. 8-15; The'odicee, Discours prelim., § 22; Letter to 
M. B., 1696, Feller, op. cit., No. VIII., pp. 26 sq. — Tr. 



ch. xvni] ON HUMAN UNDERSTANDING 591 

know that Clement of Alexandria, Justin Martyr, and St. 
Chrysostom to a certain extent were inclined thereto, 1 and 
indeed I once showed Pelisson 2 that a number of excellent 
doctors of the Soman church, far from condemning non-opin- 
ionative Protestants, even desired to save the heathen and to 
maintain that the persons of whom I have just spoken could 
have been saved by an act of contrition, i.e. penitence grounded 
in the love of benevolence, in virtue of which we love God 
above everything, because his perfections render him supremely 
lovable. - This brings it about that afterwards we are led with 
all our hearts to conform to His will and to imitate His per- 
fection in order the better to unite ourselves with Him, since it 
appears right for God not to refuse his grace to those who hold 
such views. Not to speak of Erasmus and of Ludovicus Vives, 3 

i Clement of Alexandria, born c. 150-160, date and place of death unknown. 
Cf. Strornata (or Miscellanies) , Bk. VI., chaps. 5 and 6. — Justin Martyr, 
c. 114-c. 163. Cf. First Apology, chap. 46; Second Apology, chaps. 8 and 13. 
— John Chrysostom, c. 347-407. Clement and Justin entered the Christian 
church as thinkers trained in Greek philosophy, which they regarded as the 
gift of God in preparation for the fuller light and life of Christianity — Justin 
in particular through his view of the "spermatic logos," "the seed of reason 
implanted in every race of men" ; while Chrysostom, trained in Greek rheto- 
ric and oratory, took a similar view of Greek culture as from God and not 
from the evil one. All three would naturally look upon those who lived up 
to the light they had as likely to receive more in due time, and to accept it 
and live in it when it came. — Tb. 

2 Paul Fontanier-Pellisson, 1624-1693, born and educated a Protestant, fol- 
lowed at first the profession of the law, but afterwards abandoned it for that 
of literature. He held several public offices, among others that of histori- 
ographer to Louis XIV. To obtain this position he was obliged to become a 
Catholic. He published a large number of works, among which was a Latin 
paraphrase of the first book of the Institutes of Justinian, 1645; Histoire cle 
V Acaclemie franraise jusqu'en 1662, 1653, 8vo; Traitd de VEucharistie, 1694, 
12mo, and other religious works. He corresponded extensively with Leibnitz 
on religious and theological subjects. The correspondence is contained in his 
Beflexions sur les diffe'rends en matiere de religion, 1686, and following years, 
4 vols., 12mo. Portions of the same in Dutens, Leibnitz op. om., 1, 678 sq.; 
most complete in Foucher de Careil, (Euvres de Leibniz, Vol. 1. For the 
letter here referred to by Leibnitz, cf. Dutens, op. cil., 1, 681-684, Foucher de 
Careil, op. cit. 1, 55-66; for Pellisson's replies, cf. Dutens, op. cit., 1, 697, 700- 
702, Foucher de Careil, op. cit., 1, 90-92, 96-100. For account of the controversy, 
cf. Guhrauer, Leibnitz, Eine Blog., Pt. II., 35 sq. — Tr. 

3 Juan Luis Vives, 1492-1540, a Spanish scholar and philosopher, a younger 
contemporary and friend of Erasmus, 1467-1536, and for a time the instructor 
of the Princess Mary, daughter of Henry VIII., was a persistent and success- 
ful opponent of scholastic Aristotelianism, and, as an advocate of the direct 
study of Nature by the way of experiment, the precursor of Descartes and 
Bacon. His Opera omnia appeared at Basle, 1555, 2 vols., fol., and at Valencia, 



592 LEIBNITZ'S CKITIQUE OF LOCKE [bk. iv 

I bring forward the view of Jaques Payva Andradius, 1 a 
Portuguese doctor very celebrated in his time, who was one 
of the theologians of the Council of Trent, and who said indeed 
that those who did not agree with this view made God supremely 
cruel {ixeque enim, inquit, immanitas deterior ulla esse potest). 
Pelisson found difficulty in finding this book in Paris, an indi- 
cation that authors esteemed r% their time are often neglected 
afterwards. ' This is what made Bayle think that many cite 
Andradius only upon the testimony of Chemnitius, 2 his antag- 
onist. This may indeed be so, but for myself I had read him 
before quoting him ; and his disputes with Chemnitius made 
him celebrated in Germany, for he had written in behalf of the 
Jesuits against this author, and we find in his book some par- 

1782-1790, 8 vols., fol. On his life and philosophy, cf. Stockl, Gesch. d. Philos. d. 
Mittelalters, III. [Vol. 4], 285-287 ; Ueberweg-Heinze, Gesch. d. Philos., 7th ed., 
1888, Vol. 3, pp. 24, 25 ; Lange, Gesch. d. Mate?^ialismus, Vol. 1, p. 106, Iserlohn, 
1866, Eng. trans., 1, 228, 2d ed., Boston, 1879; and Lange's article on " Vives," 
in Encykl. d. ges. Erzieh.- u. Unterrichtswesen, Vol. 9, pp. 737-814. — Tb. 

1 Diego Payva d'Andrada, 1528-1575, a celebrated theologian of one of the 
most noble Portuguese families, who, after completing his studies chiefly in 
the Scriptures and the Fathers, devoted himself with zeal to missions for 
instructing the ignorant, and was sent at the age of thirty-three by King 
Sebastian of Portugal to the Council of Trent to assist as a theologian. There 
he composed his Orthodozarum explicationum de religionis Christians capi- 
tibus lib. X. adversus hxreticos, contra Chemnicium, Venetiis, 1564, 8vo; 
and his Defensio Tridentinse fidei catholicae et integerrimse V. lib. compre- 
hensa adversus hsereticorum detestabiles calumnias et praesertim, Martini 
Chemnicii Germani, Olyssipone, 1578, 4to, Ingolstadt, 1580, 8vo. In the lat- 
ter book he maintained the opinions of Zwingli and Erasmus on the salvation 
of the heathen, in consequence of which the book was much quoted by Prot- 
estants. Leibnitz refers to him in this same connection in the Theodice'e, Pt. I., 
§ 96 ; in an excerpt from a letter to a friend written Nov. 1697, cf. Dutens, 
Leibnit. op. om., 1,33; in his letters to Pellisson, Dutens, op. cit., 1, 683, 
Foucher de Careil, QZuvres de Leibniz, 1, 65-66; and in his letters to Ant. 
Magliabecbius, No. 28, 26 Nov., 6 — Dec, 1697, Dutens, op. cit., 5, 121, and to 
Job. Fabricius, Prof, at Helmstadt, No. 16, Sept. 20, 1698, Dutens, op. cit., 
5, 235. — Te. 

2 Martin Chemnitz, 1522-1586, a German Lutheran theologian, a disciple of 
Melancthon, 1497-1560, and said to be the ablest theologian of the period imme- 
diately succeeding Luther, was Professor of Theology at Wittemberg, 1551-1554, 
and then for thirty years pastor at Brunswick. To him more than to any other 
the Lutheran church owes its purity of doctrine and compact organization. 
His Loci Theologici, Frankfort, 1591, is one of the best expositions of Lutheran 
theology as modified by Melancthon. His greatest work, the Examen Con- 
cilii Tridentini, appeared at Frankfort in four parts, 1565-1573, again in 1585, 
4 vols., fol., and in later eds. For further account of Chemnitz, cf. Schenkel's 
article in Herzog, Realencyclop., 2d ed., Leipzig, 1878, Vol. 3, pp. 184-192. 
Leibnitz refers to him also in the The'odice'e, Discours prelim. § 67. — Tr. 



en. xvin] ON HUMAN UNDEESTANDING 593 

ticulars touching the origin of this famous society. I have 
remarked that some Protestants called those Andradians, who 
were of his opinion upon the subject of which I have just spoken. 
There have been authors who have written expressly upon the 
salvation of Aristotle upon the basis of these same principles 
with the approbation of the Censors. The books also of Collius 1 
in Latin and La Mothe le Vayer 2 in French on the salvation of 
the heathen are well known. But a certain Franciscus Puccius 3 



1 Francesco Collio — Latin, Collius ("Collins" being a misprint for " Col- 
lius " in all the editions of Leibnitz's text) — was an Italian theologian of 
great learning, a doctor of the Ambrosian College at Milan, and Grand Peni- 
tentiary of the diocese of Milan from 1631 till his death in 1610. In his De ani- 
mabuspaganorum, 2 vols., 4to, Mediol. 1622-1623, 2d ed., 1738-1740, he discussed 
the question of the eternal salvation of the pagans, deciding as to the fate of 
individuals on the ground of their knowledge of divine things, their moral 
life, sentiments and writings, and the testimony regarding them given by eccle- 
siastical and profane writers. He considers Aristotle as unsaved. Dupin, 
Bibl. des Aut. eccle's., 1711, torn. 17, pp. 109-116 sq., gives a long abstract from 
this work, and an estimate of its character and value. Of. also Tiraboschi, 
Storia tlella Letter atur a Italiana, Vol. 14 [Tomo VIII, Parte Prima, ed. Rome, 
1782-1784], pp. 167-168, Milan, 1824. — Tk. 

2 Francois de La Mothe le Vayer, 1588-1672, a French writer and philos- 
opher, was from 1652-1660 the instructor of Louis XIV. of France, for whom 
he composed many elementary treatises on various subjects of study. The book 
here referred to by Leibnitz is his De la vertu des pa'iens, Paris, 1642, 4to., 
3d ed., 1647. The subject is treated in the conclusion of Pt. I., cf. CEuvres, 
Vol. 1, p. 582, Paris, A. Courbe, 1662. The best ed. is that published at Dres- 
den, 1756-1759, 7 vols, in 14, 8vo. The De la vertu des patens — avec les preuves 
des citations mises sous le texte — is found in Vol. 5, pp. 1 sq. of this ed. 
Le Vayer goes back to the Church Fathers and later ecclesiastical writers, 
and gives much literature. — Tr. 

3 Francesco Pucci, an Italian theologian (died 1660), was led to devote him- 
self to theology by his participation in religious controversies at Lyons, whither 
he had gone to learn commerce. Adopting mostly Protestant ideas, he went 
to England, where he received an Oxford M.A. in 1574. Opposing, in his De 
fide in Deum, quse el quails sit, the Calvinism then ruling at Oxford, he went 
to Basle and joined himself to F. Socinus, but soon returned to England in 
consequence of persecution on account of his views on universal grace, put 
forth in theses entitled Universurn genus humanum in ipso matris utero 
efficaciter particeps esse beneficiorum Ghristi et vitse immortalis et beatse, etc. 
He finally became a Catholic, 1588, and secretary of Cardinal Pompei. In his 
De immortalitate naturali primi hominis ante peccatum he combatted certain 
ideas of Socinus, and in his De Christi Salvationis efficacitate omnibus et sin- 
gulis hominibus quatenus homines sunt assertio catholica, Gouda, 1592, 8vo, 
he maintained the view that all men could be saved through the natural power 
of reason, or through the natural belief in the Creator. He proposed to prove 
by Scripture and the Fathers that Christ by his death made satisfaction for all 
men, so that all having a natural knowledge of God will be saved, although 
having no knowledge of Jesus Christ. — Tk. 

2Q 



594 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

went too far. St. Augustine, wholly clever and penetrating as 
he was, threw himself into another extreme view, even con- 
demning infants dying without baptism, 1 and the Scholastics 
appear to have been right in abandoning it ; although persons 
otherwise clever and some of great merit, but of a disposition a 
little misanthropic in this respect, desired to revive this doctrine 
of this Father and have perhaps exaggerated it. /This spirit 
also may have had some influence in the dispute between several 
excessively vehement doctors and the Jesuit missionaries in 
China, who had insinuated that the ancient Chinese had had 
the true religion of their time and the true saints, and that the 
doctrine of Confucius was in no respect idolatrous or atheistic. 
It seems that there was more reason in Eome in being unwilling 
to condemn one of the greatest nations without understanding it. 
It is well for us that God is more philanthropic than men. I 
know some persons who, thinking to show their zeal by severe 
opinions, fancy that we cannot believe in original sin without 
being of their opinion, but in this they are mistaken. And it 
does not follow that those who justify the heathen, or others 
who lack ordinary aid, must attribute it to the forces of nature 
only (although perhaps some Fathers were of this opinion), since 
we may maintain that God in giving them the grace exciting 
an act of contrition gives them also, either explicitly or virtu- 
ally, but always in a supernatural way, before they die, even if 

1 On this and the immediate context, cf. The'odice'e, Pt. I., §§ 92-95, Pt. III., 
§ 283. Augustine's view is found in his works passim. Cf., among others, 
Enchir. ad Laurent., chap. 43; Be nuptiis et concupiscentia, Bk. I., chap. 22, 
with which cf. Contra Julianum Pelagianum, Bk. III., chap. 12 (infants under 
the power of the devil on account of original sin — the "potestas diaholi" is 
"peccatum originale"), and Bk. V., chap. 44; Contra duas epist. Pelag., 
Bk. IV., chap. 4 ; Be peccatorum meritis et Remissione et de Baptismo Parvu- 
lorum, Bk. I., chap. 25, Bk. III., chap. 7; Be peccato originale, chap. 36; Be 
civitate Bel, Bk. XIII., chap. 14. Cf. also Shedd, Hist, of Christ. Boct., 2, 76, 
note 2, 77, note 1; Hagenbach, Hist, of Boct., ed. H. B. Smith, 1, 360, and 
trans, from later German ed. T. & T. Clark, 1880, 3 vols., Vol. 2, pp. 73 sq. 
Augustine believed that infants because of hereditary depravity — original 
sin — belonged to the " massa perditionis," and, unless relieved from the pen- 
alty therein inhering by the sacrament of baptism, which was thus a means of 
salvation to the infant, must incur the penalty and be lost. Their condemna- 
tion, however, since they were guilty of no personal sin, would be the lightest 
of all — " in damnatione omnium levissima " (C. Jul. Pelag., V. 44) . 

For a brief, but most excellent and satisfactory, discussion of the Salvation 
of Infants, cf. E. G. Robinson, Christian Theology, § 28, pp. 164-169, Roches- 
ter, N.Y., Press of E. R. Andrews, 1894. — Tr. 



ch. xvin] ON HUMAN UNDERSTANDING 595 

only at the last moment, all the light of faith and all the warmth 
of love necessary to their salvation. Thus it is that the Reform- 
ers explain with Vedelius the view of Zwingli, 1 who had also 
expressed the same view npon this point of the salvation of the 
virtuous men of Paganism, as the doctors of the Roman church 
have done. This doctrine also has nothing in common for that 
reason with the particular doctrine of the Pelagians or Semi- 
Pelagians, from which we know that Zwingli was far removed. 
And since we teach against the Pelagians a supernatural grace 
in all those who possess faith (in which the three received 
religions agree, excepting perhaps the disciples of Pajon) 2 and 
as they allow also either faith or at least similar movements to 
infants who receive baptism, it is not very extraordinary to 
allow as much at least in the article of death to persons of good 
will who have not had the good fortune to be instructed as 
usual in Christianity. 3 But the part of the wisest is to deter- 
mine nothing upon points so little known, and to content him- 
self with the general judgment that God can do nothing which 
is not full of goodness and justice : melius est dubitare de 
occultis quam Utigare de incertis (Augustine, lib. 8, Genes, ad 
lit. c. 5). 

J iUlrich Zwingli, 1484-1531, introduced the Reformation into Switzerland 
about the same time that Luther, 1483-1546, introduced it into Germany. 
His view on the salvation of the heathen, a consequence of his milder view 
of original sin or innate depravity, is found in his Christ. Ficlei brevis et clara 
expositio, Werke, ed., Schuler u. Schulthess, Zurich, 1828-1842, 8 vols., Vol. 
4, pp. 42-78. In his treatise De Provulentia (ibid.,Y6\. 4, pp. 79-144) he 
advanced the principle that pagans who have acknowledged the true God 
and have led a good life, such as Socrates and Seneca, are capable of being 
saved without, faith ; and he extended this principle to all who have no 
knowledge of the gospel. — Tr. 

2 Claude Pajon, 1626-1685, a French Protestant theologian, Professor of 
Theology at Saumer, 1666, and later pastor at Orleans. Pajon taught that 
in conversion the Holy Spirit did not act immediately or irresistibly upon the 
heart, but that the soul was itself active in the work of salvation, allowing 
itself to be convinced by the efficacious word of truth found in Scripture with 
which the Spirit's influence was intimately united. His views were opposed 
by both Lutherans and Reformed. For further account of him, cf. Alex. 
Schweizer, Central-Do c/men cl. Reform. Kirche, 2 vols., 1854-1856, Vol. 2, pp. 
564-663, and in Herzog, Realencyclop. 2d ed., Leipzig, 1883, Vol. 11, pp. 161- 
163; W. Gass, Gesch. d.prot. Dogmatik, 2, 359 sq.— Tr. 

3 Cf. Feller, Otium Hanoveranum, No. LXXXVIII., pp. 181-183 (Dutens, 6, 
311, 312). — Tr. 



590 LEIBNITZ'S CRITIQUE OF LOCKE [bk. 



CHAPTER XIX 

OF ENTHUSIASM 

§ 1. Ph. [Would to God that all theologians and St. Augus- 
tine himself had always practised the maxim expressed in 
this passage.] But men think that the dogmatic spirit is an 
indication of their zeal for the truth, while it is wholly the 
contrary. We love the truth in reality only in proportion as 
we love to examine the proofs which make it what it is. And 
when we judge hastily we are always pressed by less sincere 
motives. § 2. The spirit of authority is not one of the less 
common motives, and a certain satisfaction it has in its own 
reveries is another motive which causes enthusiasm to spring 
up. § 3. This is the name which is given to the failing of 
those who believe an immediate revelation when it is not 
grounded in reason. § 4. And as we may say that reason is a 
natural revelation of which God is the author, just as he is 
the author of nature, we may also say that revelation is a super- 
natural reason, i.e. a reason extended upon the basis of new 
discoveries emanating directly from God. But these discov- 
eries suppose that we have the means of discerning them, 
which is reason itself; and to desire to proscribe reason in 
order to make way for revelation would be to plnck out the 
eyes the better to see the satellites of Jupiter through a tele- 
scope. § 5. The source of enthusiasm is that an immediate 
revelation is more convenient and shorter than the long and 
difhcrdt process of reasoning which is not always followed by 
a happy result. Men have been seen in all ages whose melan- 
choly mingled with devotion, united with the good opinion 
they have had of themselves, has made them believe that they 
had an altogether different intercourse with God from other 
men. They suppose he has promised it to them and believe 
themselves his people preferably to others. § 6. Their fancy 
becomes an illumination and a divine authority, and their 
plans are an infallible direction from heaven, which they are 
obliged to follow. § 7. This view has produced great results 
and caused great evils, for a man acts more vigorously when 



ch. xix] ON HUMAN UNDERSTANDING 597 

lie follows his own impulses and when the opinion of a divine 
authority is sustained by his inclinations. § 8. It is difficult 
to draw him therefrom, because this pretended certainty with- 
out proof flatters his vanity and love for that which is extraor- 
dinary. Fanatics compare their opinions to sight and feeling. 
They see the divine light as we see that of the sun at noon 
without needing the twilight of their reason to show it to them. 
§ 9. They are certain because they are certain, and their per- 
suasion is right because it is strong, for this is the result to 
which their figurative language reduces itself. § 10. But as 
there are two perceptions, that of the proposition and that of 
the revelation, we may ask them where is clearness. If it is 
in the sight of the proposition, what good is revelation ? It 
must then be in the feeling of revelation. But how can they 
see that it is God who reveals and not a will-of-the-wisp which 
leads them around this circle : this is a revelation because I 
believe it strongly, and I believe it because it is a revelation. 
§ 11. Is there anything more suited to throw one into error 
than to take the imagination for a guide ? § 12. St. Paul had 
great zeal when he persecuted the Christians and did not allow 
himself to be mistaken. We know that the devil has had 
martyrs, and if it is sufficient to be well persuaded we shall not 
be able to distinguish the delusions of Satan from the inspira- 
tions of the Holy Spirit. § 14. It is then the reason which 
makes known the truth of revelation. § 15. And if our 
belief proved it, it would be the circle of which I just spoke. 
The holy men who received the revelations of G-od had external 
signs which persuaded them of the truth of the inner light. 
Moses saw a bush which burned without being consumed, and 
heard a voice from the midst of the bush, and God, in order to 
give him more assurance concerning his mission when he sent 
him to Egypt to deliver his brethren, made use of the miracle 
of the rod changed into a serpent. Gideon was sent by an 
angel to deliver the people of Israel from the yoke of the Mid- 
ianites ; yet he demanded a sign in order to be convinced that 
this commission was given him on the part of God. § 16. I 
do not, however, deny that God sometimes illumines the minds 
of men, in order to make them understand certain important 
truths or to lead them to good acts, by the immediate influence 
and assistance of the Holy Spirit without any extraordinary 



598 LEIBNITZ'S CRITIQUE OF LOCKE [ek. iv 

sign accompanying this influence. But in these cases also we 
have reason and Scripture, two infallible rules for judging of 
these illuminations ; for if they agree with these rules we run 
at least no risk in regarding them as inspired of God, although 
it is not perhaps an immediate revelation. 

Th. Enthusiasm was at the beginning a good term. And as 
the sophism properly indicates an exercise of wisdom, enthusi- 
asm signifies that there is a divinity in us. Est Deus in nobis} 
Socrates maintained that a god or daemon 2 gave him internal 
warnings, so that enthusiasm would be a divine instinct. But 
men having consecrated their passions, fancies, dreams, and 
even their anger as something divine, enthusiasm began to sig- 
nify a mental disturbance attributed to the influence of some 
divinity, which is supposed to be in those who are smitten there- 
with ; for the soothsayers, male and female, showed a mental 
derangement, when their god seized them, as the Cumsean 
Sibyl in Vergil. 3 Since then we attribute it to those who be- 
lieve without foundation that their movements come from God. 
Msus in the same poet thinking himself pressed by I know 
not what impulse to a dangerous enterprise, in which he per- 
ished with his friend, proposed it to him in these terms full of 
a reasonable doubt : — 

Di ne lranc ardorem mentibus adclunt, 
Euryale, an sua cuique Deus fit dira cupido ? 4 

1 Ovid, Fasti, 6, 5: "Est Deus in nobis, agitante calescimus illo." — Tit. 

2 On the ctemon of Socrates, cf. Zeller, Philos. d. Griech., II., 1 [Vol. 3], 
73-91, 4th ed., Leipzig, 1889; J. S. Blackie, Four Phases of Morals, -pp. 125- 
127, New York, 1872; H. Jackson, "On the Sai^mov of Socrates" in the 
" Journal of Philology," V., and article " Socrates," Encyclop. Brit., 9th ed., 
Vol. 22, p. 240 (Araer. reprint). — Tr. 

3 Cf. Vergil, jFneid, 6, 49: " Et rabie fera cord a tument." The view here 
mentioned by Leibnitz, that persons gifted with inspiration or enthusiasm 
were also affected with some derangement or distiu'bance of the ordinary men- 
tal processes, was current in one form or another throughout all antiquity, 
and had its influence, through the contact of Greek thought with Chris- 
tianity, in shaping the Christian doctrine of inspiration. Cf. Plato, Phsedrus, 
244, Jowett's trans., 2d ed., 1875, 2, 121, 3d ed., 1892, 1, 449-450; Ion, 533-534, 
Jowett, 2d ed., 1, 247-248, 3d ed., 1, 501-503 ; Timseus, 71-72, Jowett, 2d ed.. 3, 
654-656, 3d ed., 3, 492-494; the Stoic view, Zeller, Philos. d. Griech., III., 1 
[Vol. 5], 336 sq., Plutarch, ibid., III., 2 [Vol. 6], 193 sq., Philo, 414 sq., Plo- 
tinus, 611 sq. ; Pfleiderer, Religionsphilosophie, 2d ed., 1884, 2, 339 sq., Eng. 
trans., 4, 46 sq. — Tr. 

4 Verg. Aen. 9, 184-185. — Tr. 



ch. xix] ON HUMAN UNDERSTANDING 599 

He ceased not to follow this instinct although he knew not 
whether it came from God or from an unfortunate desire to 
distinguish himself. But if he had been successful, he would 
not have failed to acquire authority in another case and to 
think himself impelled by some divine power. The enthusi- 
asts of the present think that they receive also from God the 
dogmas which they observe. The Quakers belong to this per- 
suasion, and Barclay, their first systematic author, maintains 
that they find in themselves a certain light which is made 
known by itself. 1 But why call that light which reveals noth- 
ing ? I know that there are some persons of this disposition 
of mind who see sparks and even something more luminous, 
but this image of material light excited when their minds are 
aroused gives no light to the mind. Some idiots with a restless 
imagination form conceptions which they had not before ; they 
are in a condition to say fine or at least very animated things 
in their opinion; they admire themselves and make others 
admire this fertility which passes for inspiration. This ad- 
vantage comes to them largely from a vivid imagination which 
passion rouses and from an excellent memory which has well 
retained the methods of speech of the prophetic books which 
the reading or discourse of others has rendered familiar to 
them. Antoinette de Bourignon made use of the facility she 
had in speaking and writing as a proof of her divine mission. 2 
I know a visionary who based his divine mission upon the tal- 

1 Of. Leibnitz's letter to Thos. Burnett, July 17-27, 1696 ; Gerhardt, Leibniz, 
philos. Schrift., 3, 184. On the doctrine of the " inner light," the immediate 
revelation of the Spirit of God in each individual soul, " the light that lighten- 
ed every man," — the most characteristic doctrine of the Quakers, — cf. Robert 
Barclay, 1648-1690, An Apology for the True Christian Divinity, Prop. II., 
Of Immediate Revelation; and the excellent account of Bancroft, Hist, of the 
U. S., chap. 23, Vol. 2, pp. 78 sq. , Centenary ed., Boston, 1876. — Tn. 

2 Antoinette Bourignon, 1616-1680, an enthusiast whose religious doctrines 
made considerable stir in her lifetime and for a short time after in Holland 
and Scotland, but have long ceased to have any influence and are now almost 
wholly forgotten. Her complete works in French appeared at Amsterdam, 
16S6, 19 vols., 8vo ; 1717, 21 vols., 8vo, with a life of the author by Pierre Poiret, 
1646-1719, a Calvinistic minister and famous mystic, who became her disciple, 
edited her works, and attempted to reduce to system her vague reveries in his 
(Economie de la nature, Amsterdam, 1686, 21 vols., 8vo. Her prophetic views 
were expounded in her Traite de V aveuglement des homines ((Euvres, ed. 
1686, Vol. 15), her La lumiere du monde (ibid., Vol. 7), and her De la lumiere 
nee en tenebres (ibid., Vol. 4), the last work being "a collection of letters, 
with a large explanation of Matt. 24 and 25 " ; Eng. trans. The Light of the 



600 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

ents lie had in speaking and praying alond almost an entire 
day without ceasing and without becoming exhausted. ^ There 
are some persons who, after having practised austerities or 
after a state of sadness, taste a peace and consolation in the 
soul which enraptures them, and they find therein so much de- 
light that they believe it to be an effect of the Holy Spirit. It 
is true that the contentment they find in considering the great- 
ness and goodness of God, in the accomplishment of his will, 
in the practice of the virtues, is a grace of God and one of the 
greatest ; but it is not always a grace which needs a new super- 
natural aid, as many of these good people maintain. Not long 
since there was a young lady very wise in everything else, who 
believed from her youth that she spoke with Jesus Christ and 
was his wife in a wholly peculiar manner. Her mother, to 
whom this was related, was a little given to enthusiasm, but 
the daughter having commenced early had gone very much 
farther. Her satisfaction and joy was unspeakable, her wis- 
dom appeared in her conduct, and her intelligence in her 
discourse. The thing went, however, so far that she received 
letters addressed to our Lord and she sent them back sealed 
as she received them with a reply which sometimes appeared 
appropriate and always reasonable. But finally she ceased to 
receive them from fear of making too much disturbance. In 
Spain she would have been another St. Theresa. But all per- 
sons who have similar visions do not conduct themselves in 
the same way. There are some who seek to form a sect, and 
even to make trouble : and England furnishes a strange proof 
of this. 1 When these persons act in good faith it is difficult to 

World, London, 1696; The Light risen in Darkness, London, 1703. Leibnitz 
refers to her in a fragment, Sur Vesprit Sectaire, 1697, cf. Dutens, 1, 740. For 
further account, cf. J. C. Adelung, Gesch. d. mensch. Narrheit, Leipzig, 1785- 
1789, 7 vols., 16mo, Vol. 5, pp. 245-391 ; Gottfried Arnold, Kirchen u. Ketzerhis- 
torie, Frankfort-on-the-Main, 1729, Theil. III., Cap. XVI., Vol. 2, pp. 153-176, 
Th. IV., Sect. III., Num. XVIL, Vol. 2, pp. 1065-1089; Wetzer u. Welte, 
Eirchenlexicon, Vol. 2, pp. 1167-1170, ed. 1883. — Tr. 

1 Leibnitz here refers to tbe Independents, who, arising in obscurity in Eng- 
land in the reign of Elizabetb and gradually gaining in numbers and influence 
as a result of the persecution to Avhich they were subject at the hands of the 
established Church and the State, and of their success in founding the New 
England States, came to tbe front in the time of the Revolution and changed 
at length the political as well as the religious life of England, and became 
a powerful and controlling force in the life and institutions of the American 
people. In their fundamental principle that religion is a matter of the indi- 



en. xix] ON HUMAN UNDERSTANDING 601 

reform them. : sometimes the overthrow of all their plans cor- 
rects them, but often it is too late. 1/ There was a visionary who 
lately died who believed himself immortal because he was very 
old and very well, and without having read the book of an 
Englishman lately published (who wished to make us believe 
that Jesus Christ came to exempt true believers from bodily 
death) was almost of the same opinion for some years past; 
but when he perceived that he was dying he went so far as to 
doubt all religion because it did not correspond to his chimera. 
Quirin Kulman \_sic\, x a Silesian, a man of knowledge and judg- 
ment, but who had since indulged in two kinds of visions, 
equally dangerous, the one of the enthusiasts, the other of the 
alchemists, and who made some stir in England, Holland, and 
even in Constantinople, being at last advised to go into Russia 
and there to mix himself up in certain intrigues against the 
minister, at the time when the Princess Sophia governed it, 
was condemned to be burned, and did not die like a man per- 

vidual reason and conscience, wholly free from State or other control, they 
bore in a general way a somewhat close resemblance to the Quakers and 
other enthusiasts of their time. 

In this connection Schaarschmidt ventures the conjecture that Leibnitz 
may have had his attention called to the persons and circumstances men- 
tioned in this chapter by a large work, appearing not long before, entitled, 
Anabaptisticum et enthusiasticum Pantheon, und Geistliches Riisthauss wider 
die Alten Quacker und Neuen Frey-Geister, u. s. w., Cothen, W. A. Meyer, 
1702, sinc^e his allegations strikingly call to mind this work. But may not 
Bayle's Dictionnaire as well have been the source of his information, inas- 
much as it contains considerably extended articles on the persons mentioned, 
and was a work with which Leibnitz was thoroughly familiar? — Tr. 

1 Quirin Kuhlmann, 1651-1689, in consequence of a disordered brain result- 
ing from a severe illness at the age of 18, became subject to hallucinations, 
lost his previous taste for study, claimed to possess a method by which he 
might know everything independent of the usual processes of acquisition, and 
that the Holy Ghost was his only teacher, and on these grounds considered 
himself a saint. At Leyden, falling in with the works of Boehme, he imme- 
diately became an enthusiastic disciple. It is said that he wished to marry 
Antoinette Bourignon, but that her " inviolable chastity " caused her to refuse 
him. Leaving Holland in 1675 he travelled, it is believed, in England, France, 
and Turkey. At Constantinople he addressed a letter, Aug. 1, 1678, to the 
Sultan Mahomet IV., in which he predicted the conversion of the Turks, and 
sought to win the Sultan to his views. Failing to attain his desired end, he 
went to Russia to set up the true kingdom of God, was opposed by Peter the 
Great, and after a brief trial condemned by the Greek Patriarch — it is said 
at the suggestion of a Lutheran clergyman — to be burned alive as a heretic 
in 1689. For further account, cf. Adelung, Gesch. cl. mensch. Narrheit, Vol. 
5, pp. 3-90 (allusion to his alchemistic impostures, ibid., pp. 52, 53, 65, 81) ; 
Wetzer und Welte, Kirchenlexicon, 7, 1237. — Tr. 



602 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

suaded of that which, lie had preached. The dissensions of these 
people among themselves ought further to convince them that 
their pretended internal ivitness is not divine ; and that other 
signs are necessary to justify it. The Labadists, 1 for exam- 
ple, do not agree with Mademoiselle Antoinette, and although 
William Penn appears to have had the design in his travels in 
Germany, of which he has published an account, of establish- 
ing a kind of understanding between those who rely upon this 
witness, he does not appear to have succeeded. 2 J It is desira- 
ble for the truth's sake that good people be intelligent and 
act in concert: nothing would be more capable of rendering 
the human race better and happier, but it would be necessary 
for them to be truly of the number of the good people, i.e. 
of the beneficent, and, further, docile and reasonable ; instead 

1 The Labadists were a mystic sect or community of the Eeformed Church 
founded by Jean de Labadie, 1610-1674, a noted Pietist or Mystic, who, origi- 
nally a Roman Catholic, had become a Protestant, joined the Reformed Church, 
and afterwards at the head of his separatist congregation at Middleburg 
developed his scheme for the reformation of that ecclesiastical body. His 
doctrine was in many points similar to that of the Anabaptists. Labadie 
and his disciples wished to settle with A. Bourignon at Noordstrandt, but she 
would not consent, saying: "I perceive and know that we can never agree 
together. Their opinions and the spirit that governs them are altogether con- 
trary to my light and the spirit that governs me." Leibnitz refers to Labadie 
in the Theodicee, Discours prelim., § 14; in a letter to Theophilus Spizel, 
April 7, 1671, Dutens, 5, 351-352; cf. also, Guhrauer, Leibnitz's deutsche 
Scluift., 2, 498-499. For further account, cf. the writings of two of his most 
enthusiastic disciples, Pierre Yvon, Abrege" pricis de la vie et de la conduite 
et des vrais sentiments de feu M. de Labadie; Anna Maria v. Schiirman, 
JEucleria (said to be, perhaps, the best exposition of his views), Altona, 1673, 
1678; also Arnold, Kirchen und Ketzerhistorie, Theil. II., Buch. XVII., Cap. 
XXL, Vol. 1, pp. 1186-1200 ; Vol. 2, pp. 1302-1350 ; H. van Berkum, De Labadie 
en de Labadisten, Sneek, 1851 ; Goebel, Gescli. d. christ. Lebens in d. rhein- 
isch-westphalischen Kirche, Vol. 2, Coblentz, 1852 ; Heppe, Gesch. d. Pietis- 
mus, Leyden, 1879; Ritsche, Gesch. d. Pietismus, Vol. 1, Bonn, 1880. — Tr. 

2 William Penn, 1644-1718, made a missionary journey through Holland 
and Germany in 1671-1672, in the course of which he founded a Quaker society 
at Embden and became an intimate friend of the Princess Elizabeth of the 
Palatinate, to whom Descartes dedicated his Princip. Philos. His letters 
written during this journey contain a full account of the doctrine of the 
"inward light." In 1677 he made another missionary journey to the Conti- 
nent, and published in 1694 a full account of the same, entitled Journal of my 
Travels in Holland and Germany. Cf. A Collection of the Works of Wm. 
Penn, London, 2 vols., fol., 1726, Vol. 1, pp. 50-116 ; Select Works, 3d ed., Lon- 
don, 1782, 5 vols., 8vo, Vol. 3, pp. 373 sq. For short selections therefrom, cf. 
Janney, Life of Wm. Penn, chap. 9, pp. 125-137, 4th ed. revised, Phila., 1878; 
for more extended extracts, cf. Passages from the Life and Writings of Wm. 
Penn, Phila., 1882, VIII., pp. 141-199. — Tr. 



ch. xix] ON HUMAN UNDERSTANDING 603 

of "which only too many of those who are called devout to-day 
are accused of being severe, imperious, obstinate. Their dis- 
sensions make it appear at least that their internal witness 
needs an external verification in order to be believed, and mir- 
acles would be necessary in order for them to have the right 
to pass as prophets and inspired men. There might, however, 
be a case where these inspirations would carry their proofs 
with them. This would be if they really enlightened the mind 
by important discoveries of some extraordinary knowledge, 
which without any external aid would be beyond the powers 
of the person who should have acquired them. If Jacob 
Boehme, 1 a famous shoemaker of Lusace, whose writings have 
been translated from German into other languages under the 
name of the Teutonic Philosopher, and in reality possess some- 
thing of grandeur and beauty for a man in this condition, had 
known how to make gold, as some are persuaded he did, or as 
St. John the evangelist did, if we believe what is said in a 
hymn 2 composed in his honor : — 

Inexhaustum fert thesaurum 
Qui de virgis fecit aurum, 
Gemmas de lapidibus, 

there would have been some reason for giving more credence 
to this extraordinary shoemaker. And if Mademoiselle Antoi- 
nette Bourignon had furnished to Bertrand la Coste, a French 
engineer at Hamburg, the light in the sciences which he believed 
he had received from her, as he indicated in dedicating to her 
his book on the Quadrature of the Circle (in which, making 
allusion to Antoinette and Bertrand, he called her the A in 
theology, as he said he himself was the B in mathematics), we 
should not have known what to say. 3 But we do not see exam- 

i Qf. ante, p. 298, note 1. — Tb. 

2 Qf. L. Gautier, (Euvres Poetiques d'Adam de S. -Victor, Paris, 1858, 2 
vols., 12mo, Vol. 1, p. 229, and the editor's learned note; D. S. Wrangham, 
Tlie Liturgical Poetry of Adam of St. Victor, from the text of Gautier, loith 
trans, into English in the original metres, etc., 3 vols., London, Kegan 
Paul, 1881, Vol.1, p. 190. Leibnitz probably knew the hymn in Clichtoveus, 
Elucidatorium Ecclesiasticum, Pt. IV., of which there were several editions 
from 1515-1556, at Paris, Basel, Geneva. — Tit. 

3 Bertrand de Lacoste, a French engineer, born early in the 17th century, 
who, after some service as colonel of artillery in the army of the Duke of 
Brandenburg, obtained his discharge in 1663 and retired to Hamburg, where 
he devoted himself to the study of mathematics in general, and in particular 



604 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

pies of a considerable success of this nature, nor well-detailed 
predictions which have succeeded in the case of such persons. 
'The prophecies of Poniatovia, 1 of Drabitius and others, which 
the good man Comenius 2 published in his " Lux in Tenebris," 
and which contributed to the disturbances in the hereditary 
lands of the emperor, were found false, and those who believed 
them were unfortunate. Ragozky, Prince of Transylvania, was 
impelled by Drabitius 3 to the attack upon Poland in which he 

to the problem of the quadrature of the circle. On this subject he published 
two works : Scheda de inventa quadratura circuit, 1663, and, in reply to a 
refutation of the same by Prof. Miiller, Demonstration de la quadrature du 
cercle, Hamburg, 1666, 4to, 1677, 8vo. A Flemish translation appeared in 
1677, with the title Klarer Bewys von't Quadrat des Cirkels, dedicated to 
Antoinette Bourignon, whose person and teachings he for a time greatly 
admired ; but failing to interest her equally in his mathematical studies, he 
finally opposed her and her doctrines as strongly as he had before advocated 
them, exciting the populace of Hamburg against her and forcing her to 
leave the city. He wrote against her bis Scheda contra Ant. Bourignoniam. 
— Tr. 

1 Christine Poniatowa, 1610-1644, a famous enthusiast, the daughter of a 
Polish noble and unfrocked monk, claimed in 1627-1628 that she had visions 
regarding the persecutions of the Evangelical Church which were soon to end 
in its triumph. Jan. 27, 1629, she fell into a lethargy so profound that they 
thought her dead; but at length awaking, she declared that her visions were 
ended, her mission complete. Chagrin at seeing her predictions denied at 
last caused her death. She wrote out her revelations in the order in which 
she said she had received them from heaven. Comenius (cf. ante, p. 466, 
note 2) translated them into Latin, and published them, together with those 
of Drabitius, Kotter, 1585-1647, and other enthusiasts, in his very rare Lux 
in Tenebris, 1650, 1657, 4to, 1659, with title Historia revelationum Ch. Kotteri, 
Chr. Poniatovise, Nic. Drabitii, etc. (the only ed. known to Bayle, and the 
least rare and complete), 1665, 2 vols., 4to, also several other eds., more or 
less incomplete. The rarity of the work is due to the fact that Comenius, 
fearing on the one hand to disobey a divine command if he refused to trans- 
late these prophecies out of the Bohemian or Czech language in which they 
had first appeared, and on the other of covering himself with ridicule if the 
event not far distant did not verify them, allowed but few copies to be printed. 
For further account of Poniatowa, cf. Adelung, Gesch. d. mensch. Narrheit, 
Vol. 6, pp. 231-267. — Tr. 

2 Of. ante, p. 466, note 2. The Lux in Tenebris appeared in 1650. — Tr. 

3 Nicolas Drabitius or Drabicius, c. 1587-1671, a Bohemian-Moravian min- 
ister at Drakatutz, who was compelled by the severity of the imperial edicts 
against the Protestants to retire to Lednitz in Hungary, turned to secular 
pursuits, became very dissipated, and was suspended from the ministry. In 
1638 he claimed to be inspired and to have divine revelations, the chief of 
which predicted the fall of the House of Austria in 1657, and the success of the 
expedition, which he urged upon Prince George II. Rakoczy of Transylvania, 
against Poland in the same year. Both predictions failed. Prince George 
was totally defeated July 16, 1657, and compelled to fight the Turks, roused 
to hostility by his attack on Poland, till his death, June 26, 1660. The House 



ch. xix] ON HUMAN UNDERSTANDING 605 

lost his army, a result which finally cost him the loss of his 
estates together with his life ; and the poor Drabitius a long 
time after, at the age of eighty years, at last had his head cut 
off by the order of the emperor. J Yet I do not doubt that there 
are people now who cause these predictions to be revived inaptly 
in the present conjuncture of disorders in Hungary, not consid- 
ering that these pretended prophets spoke of the events of their 
time ; in which respect they did almost as he who, after the 
bombardment of Brussels, published a loose sheet, in which 
there was a passage taken from a book of Mademoiselle Antoi- 
nette, who did not wish to come into this city because (if I 
remember rightly) she had dreamed that she saw it on fire ; but 
this bombardment happened a long time after her death. I 
knew a man who went to France during the war which was ter- 
minated by the Peace of Nimwegen to importune M. de Mon- 
tausier l and M. de Pomponne 2 upon the trustworthiness of the 
prophecies published by Comenius ; and he would himself have 
believed himself inspired (I think), if he had happened to make 
his propositions in a time parallel to ours. This shows not only 
the little foundation, but also the danger of these wayward- 
nesses. Histories are full of the bad effect of false or misunder- 
stood prophecies, as may be seen in a learned and judicious 
dissertation, " De officio viri boni circa futura contingentia," 
which the late Jacobus Thomasius, a celebrated professor at 
Leipzig, formerly gave the public. 3 ; It is true, however, that 

of Austria, resolving to rid itself of the pretended prophet, arrested him as 
a state criminal, tried and condemned him to death. His head and right 
hand were cut off and burned with a copy of his books, and the ashes thrown 
into the Danube, July 17, 1671. For further account, cf. Adelung, Gesch. d. 
m.ensc7i. Narrheit, Vol. 2, pp. 27-62. — Tr. 

1 Charles de Sainte-Maure, Marquis and then Duke de Montausier, 1610-1690, 
to whom Louis XIV., in 1668, entrusted the education of the Dauphin, then 
seven years of age, for whose instruction he edited the Delphine Classics and 
a Recueil de maximes morales et politiques. — Tr. 

2 Simon Arnauld, Marquis de Pomponne or Pompone, 1618-1699, was am- 
bassador to Sweden under Louis XIV., and concluded the Peace of Nimwegen, 
1678-1679. His Memoires de Marquis de Pomponne appeared at Paris, 1861- 
1863, 2 vols., 8vo. — Tr. 

3 Jacob Thomasen, — Latin Thomasius, — 1622-1684, was for many years 
Professor of Philosophy and Eloquence in the University of Leipzig, the 
founder of the scientific study of the history of philosophy in Germany, and 
the first to recommend disputed questions in this subject as themes for dis- 
sertations. He was Leibnitz's first teacher in philosophy, early discerned 
the eminent abilities and promise of his subsequently very distinguished 



GOG LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 



these persuasions sometimes produce a good effect and render 
great service, for God can make use of error to establish or 
maintain truth. But I do not believe that it is easily permitted 
us to make use of pious frauds for a good end; and as for the 
dogmas of religion, we have no need of new revelations ; it is 
enough that we propose to ourselves salutary rules in order that 
we may be obliged to follow them, although the one proposing 
them performs no miracle. And although Jesus Christ was pro- 
vided with miracles, he did not cease to refuse sometimes to per- 
form them in order to please that perverse race who demanded 
signs, when he preached only virtue and what had already been 
taught by natural reason and the prophets. 1 

pupil, taught lrini to take a broad and, for that time, critical view of the 
history of philosophy, and introduced him early into the polemic against em- 
piricism. ^ The pupil regarded his teacher with reverent gratitude (cf. Leib- 
nitz's letters to Thomasius, April 20-30, 1669, Gerhardt, Leibniz. Philos. 
Schrift., 1, 15, 26-27 ; to J. Christ. Wolf, Dec. 11, 1711, Dutens, 5, 447, Kortholt, 
Leibnit. Enist., 1, 270; Leibnit. Vita a Jac. Brucke.ro scripta, § 3, Dutens, 
1, LVIII.-LXI., and Brucker, Philos. Historia, 5, 336-340, Lipsiae, 1742-1767), 
and each prized the esteem and friendship of the other. Leibnitz sent Tho- 
masius his own early works for criticism ("Neque vero laudem, sed examen 
peto," letter of April 20-30, 1669, G. 1, 27) ; Thomasius presided when Leib- 
nitz defended his De princ. indiv. for the degree of Bachelor of Philosophy 
(cf. ante, p. 239, note 1) , and when it was published wrote the Preface (for 
which cf. Dutens, 2, Pt. I., 11-14). For their correspondence, the preservation 
of Leibnitz's part of which we owe to the care of Thomasius, cf. Gerhardt, 
op. cit., 1, 1-39. Most important for the philosophy of Leibnitz, especially as 
regards the beginning of his independent speculations, and as a statement of 
principles from which he never departed but simply worked out into clearer 
and completer forms, is the letter of April 20-30, 1669, cf. G. 1, 15-27, Erd- 
mann, 48-54, Dutens, 4, 7-19, also Guhrauer, Leibniz' Dissert, de princ. indiv., 
p. 33. Leibnitz refers frequently to Thomasius ; cf. for example, Theodicee, 
Pt. II., §§ 184, 220. 

The essay of Thomasius here referred to by Leibnitz is also cited, accord- 
ing to Schaarschmidt, under the title De officio hominis circa nolitiam futu- 
rorum contingentium, and, in his opinion, is probably the same as the one 
which Christian Thomasius, after his father's death, had printed in his Disser- 
tationes LXIII. magnam partem ad historiam philosophicam et ecclesiasticam 
pertinentes, Halle, 1693, 8vo, as Programma XXXVI. , p. 396, under the title, 
De provisione circa futura contingentia. Thomasius was the author of a 
great number of dissertations, full of research and written with purity and 
elegance. One of them, Origines historise. philosophical et ecclesiastical, Leip- 
zig, 1665, 4to, ed. by Ch. Thomasius, Halle, 1699, Svo, was for a long time the 
most accurate history of ancient philosophy. Brucker was greatly indebted 
to it.— Tr. 

^ Cf. ante, pp. 553, note 1, 582. Leibnitz, while admitting the possibility 
and on sufficient and proper evidence the actuality of miracles, nevertheless 
regards them from the philosophic point of view as exceptional and relatively 



en. xx] ON HUMAN UNDERSTANDING 



CHAPTER XX 

OF ERROR 

§ 1. Ph. After having spoken of all the means which make 
us know or divine the truth, let us also say something about 
our errors and bad judgments. Men must often be mistaken 
since there are so many dissensions among them. The reasons 
of this may be reduced to these four : (1) the lack of proofs ; 
(2) little skill in using them ; (3) lack of will to make use of 
them ; (4) false rules of probability. § 2. When I speak of the 
lack of proofs, I understand also those which we might find if 
we had the means and the opportunity, but this it is which we 
most frequently lack. Such is the condition of men whose 
life is passed in seeking their subsistence : they are as little 
informed of what goes on in the world, as a draught horse who 
always goes by the same road may become skilled in the map 
of the country. They would require languages, reading, con- 
versation, observations of nature and the experiments of art. 
§ 3. Now, all this not agreeing with their condition, shall we 
say then that the bulk of men are led to happiness or misery 
only by blind chance ? Must they abandon themselves to the 
current opinions and authorized guides in the country, even as 
regards eternal happiness or misery ? Or will they be eternally 
unhappy to have been born rather in one country than in 
another ? We must admit, however, that no one is so com- 
pletely occupied with the care of providing for his subsistence 
as to have no time left to think of his soul and to be instructed 
in that which concerns religion, if he were to apply himself 
thereto as he does to less important things. 

Th. Suppose that men are not always in a condition to 
instruct themselves, and that not being able to give up with 

unimportant, and emphasizes, as here, the view that the essence of Christianity- 
consists in its ethical content, a content intrinsically rational and accordant 
with nature. In addition to the authors referred to, ante, p. 553, note 1, cf. 
Piinjer, Gesch. d. christ. Religionsphilos., 1, 359-360, 372-375, Eng. trans., 
480-515, espec. 485-486, 501-504; and for an acute and able discussion of 
Miracles, their idea, office, etc., cf. E. G-. Robinson, Christian Theology, § 20, 
pp. 103-109, Rochester, N. Y., Press of E. R. Andrews, 1894. — Tk. 



608 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

prudence the care of the subsistence of their family in order 
to investigate difficult truths, they are obliged to follow the 
opinions authorized among them, it will always be necessary 
to judge that in the case of those who have the true religion 
without having its proofs, internal grace will supply the lack 
of the motives of credibility, and charity makes us also judge, 
as I have already indicated to you, that God does for persons 
of good will, brought up among the thick darkness of the most 
dangerous errors, all that his goodness and justice demand, 
although perhaps in a way which is unknown to us. We have 
histories commended in the Eoman church of persons who have 
been expressly raised up in order that salutary aid be not want- 
ing. But God can assist souls by the internal operation of 
the Holy Spirit, without the need of so great a miracle ; and 
because it is good and consoling for the human race to put itself 
in the condition of the grace of God, only the good but sincere 
and serious will is needed. I admit that we have not indeed 
this good will without the grace of God, forasmuch as all 
natural or supernatural good comes from him ; but it is always 
enough that we must only have the will, and that it is impos- 
sible that God can demand a condition easier and more reason- 
able. 

§ 4. Ph. There are those who are sufficiently at their ease to 
have all the opportunities suited to illumine their doubts ; but 
they are deterred from this by obstacles full of craftiness, which 
it is easy enough to see, while it is not necessary to display them 
in this place. § 5. I prefer to speak of those who lack the skill 
to avail themselves of the proofs which they have, so to speak, 
under their hand, and who cannot retain a long course of argu- 
ment nor weigh all the circumstances. There are some people 
of a single syllogism, and there are some of two only. This is 
not the place to determine whether this imperfection arises from 
a natural difference of the souls themselves or of the organs, or 
whether it depends upon the lack of exercise which polishes the 
natural faculties. It is sufficient for us here that it is visible, 
and that we have only to go from the palace or from the 
exchange to the hospitals and small houses to perceive it. 

Th. It is not the poor alone who are needy ; certain rich 
people lack more than they, because these rich people demand 
too much and put themselves voluntarily in a kind of poverty 



ch. xx] ON HUMAN UNDERSTANDING 609 

which hinders them from applying themselves to important con- 
siderations. Example does much here. One tries to conform 
to that of his equals, so that he is compelled to practise without 
showing a spirit of perverseness, and that makes it easy for him 
to become like them. It is very difficult to satisfy at the same 
time reason and custom. As for those who lack capacity, they 
are fewer perhaps in number than you think ; I think that 
good sense with application can suffice for everything which 
does not demand promptness. I presuppose good sense, be- 
cause I do not think you would demand the search for truth 
from the dwellers in small houses. It is true that there are 
not many who could not learn something of it, if we knew the 
means of so doing and what original difference exists between 
our souls (as I believe does in reality exist) ; it is always cer- 
tain that one soul might go as far as another (but not perhaps 
so rapidly) if it were led as it should be. 

§ 6. Ph. There is another sort of people who lack only will. 
A strong attachment to pleasure, a constant application to what 
concerns their fortune, a general idleness or negligence, a par- 
ticular aversion to study and meditation, prevents them from 
thinking seriously of the truth. There are even some who 
fear that a research free from all partiality would not be fa- 
vorable to the opinions which most suit their prejudices and 
plans. We know persons who will not read a letter which 
they suppose brings bad news, and many people avoid agreeing 
upon their accounts or informing themselves of the state of 
their property, for fear of learning what they would desire 
always to be ignorant of. There are some who have large rev- 
enues and employ them all in provisions for the body without 
dreaming of the means of perfecting the understanding. They 
take great care always to appear in a suitable and brilliant 
equipage, and they suffer without difficulty their soul to be 
covered with the wretched rags of prejudice and error, and its 
nakedness, i.e. its ignorance to appear as an eccentricity. Not 
to speak of the interest they ought to take in a future state, 
they do not in the least neglect what they are interested to 
know in the life they lead in this world. And it is strange 
that very often those who regard power and authority as an 
appanage of their birth or their fortune, carelessly abandon it to 
people of a condition inferior to theirs, but who surpass them 
2r 



610 LEIBNITZ'S CEITIQUE OF LOCKE [bk. iv 

in knowledge. For it is very necessary that the blind be led 
by those who see, lest they fall "into the ditch, and there is no 
worse slavery than that of the understanding. 

Th. There is no more evident proof of the negligence of men 
as regards their true interests, than the little care they take to 
know and practise what agrees with their health, which is one 
of our greatest blessings ; and although the great feel as much 
and more than others the bad effects of this negligence, they 
do not alter their course. As far as faith is concerned, many 
regard the thought which would lead to its discussion as a 
temptation of the devil, which they think they can the better 
surmount only by turning their minds to an entirely different 
thing. Men who only love pleasure, or who are attached to 
some occupation, are wont to neglect other matters. A player, 
a hunter, a drinker, a debauchee, and even a man curious about 
trifles, will lose his fortune and his property for lack of giving 
himself the trouble to institute a process or to speak to the 
men in a guard-house. There are some like the Emperor 
Honorius, who, when the news of the destruction of Rome 
was brought to him, thought it was his hen who bore this 
name, and this offended him more than the truth. 1 It is 
desirable that men who have power have knowledge in pro- 
portion ; but if the details of the sciences, of the arts, of 
history and languages, should not be theirs, a solid and prac- 
tised judgment and a knowledge of things equally great and 
general, in a word, summa rerum, might suffice. And as the 
Emperor Augustus had an abstract of the forces and needs of 
the State which he called Breviarium Imperii, he might have 
an abstract of human interests which would deserve to be called 
Enchiridion Sapiential, if men would care for that which is of 
most importance to them. 

§ 7. Ph. Finally, the majority of our errors arise from the 
false measures of p>robability which we take, whether by sus- 

1 The anecdote here mentioned by Leibnitz is thus given by Giovanni Bat- 
tista Egnazio, 1473-1553, in his Be Romanis principibus, Lib. III., Venice, 
1516, near the end of Book I. (cf. Haurisius, Scriptores historise Romanes 
Latini veteres, quse extant omnes, Heidelberg, 1743-1745, 3 vols., fob, Vol. 3, 
p. 625) : " Quum nuntiatum Honorio esset Ravennse Romarn perditam, cre- 
didit ille de pugnaci Gallo, cui nomen erat Romas, significatum esse : admira- 
tumque vehementer tarn subito periisse earn quo cum paullo ante festivissime 
luserat." — Tk. 



ch. xx] ON HUMAN UNDERSTANDING 611 

pending our judgment in spite of manifest reasons, or in giving 
it notwithstanding contrary probabilities. These false measures 
consist (1) in doubtful propositions taken as principles, (2) in 
the accepted hypotheses, (3) in the dominant passions or incli- 
nations, (4) in authority. § 8. We ordinarily judge of truth by 
its conformity with what we regard as indisputable principles, 
and this makes us despise the testimony of others and indeed 
of our own senses when they appear contrary thereto: but 
before relying upon these with so much assurance, we should 
examine them with the utmost exactness. § 9. Children receive 
the propositions taught them by their father and mother, nurses, 
teachers and others who are about them, and these propositions 
having taken root, are regarded as sacred as a Urim and Thum- 
mim which God might himself have put in the soul. § 10. 
We have some difficulty in admitting that which clashes with 
these internal oracles, while we believe the greatest absurdities 
which agree with them. This appears in the extreme obstinacy 
which we notice in different men who believe strongly opinions 
as directly opposed as the articles of faith, although they are 
very often equally absurd. Take a man of good sense, but per- 
suaded of this maxim that lie must believe what they of his 
communion believe, as they teach at Wittenberg or in Sweden, 
what disposition has he not to receive without difficulty the 
doctrine of consubstantiation, and to believe that one and the 
same thing is flesh and bread at the same time. 

Th. It is very apparent, sir, that you have not been suffi- 
ciently instructed in the views of the Evangelicals, 1 who admit 
the real presence of the body of our Lord in the Eucharist. 
They have explained a thousand times that they do not mean 
the consubstantiation of bread and wine with the flesh and blood 
of Jesus Christ, and still less that one and the same thing is 
flesh and bread at the same time. They teach only that, in 
receiving the visible symbols, we receive in an invisible and 
supernatural manner the body of our Saviour, without its being 
enclosed in the bread ; and the presence which they mean is 
not local or spatial, so to speak, i.e. determined by the dimen- 
sions of the present body, so that all that the senses can oppose 

1 I.e. Lutherans. For the views and controversies regarding the Eucharist, 
and the Confessions alluded to in the remainder of this section, cf. the various 
Church Histories and Histories of Doctrine. — Tr. 



612 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

to it does not concern them. And in order to show that the 
inconveniences which may be derived from reason no longer 
affect them, they declare that what they mean by the substance 
of the body does not consist in extension or dimension ; and 
they make no difficulty in admitting that the glorious body of 
Jesus Christ preserves a certain ordinary and local presence, 
but congruous with his position in the exalted place where he 
is found, altogether different from this sacramental presence 
herein questioned, or from his miraculous presence by which he 
governs the church, which causes him to be not everywhere 
like God, but there where he prefers to be. This is the view of 
the more moderate, so that, in order to show the absurdity of 
their doctrine, it would be necessary to show that the entire 
essence of the body consists only in extension, and in that 
which is solely measured thereby, which no one, so far as I 
know, has yet done. This whole difficulty also concerns not 
less the Reformers who follow the Gallican and Belgian confes- 
sions, the declaration of the Council of Sendomir, composed of 
people of the two confessions, Augustan and Swiss, conformed 
to the Saxon confession, destined for the Council of Trent ; the 
profession of faith of the Eef ormers who came to the Conference 
of Thorn, convoked under the authority of Vladislas, King of 
Poland, and the constant doctrine of Calvin and of Beza, who have 
declared the most distinctly and the most strongly of everybody 
that the symbols really furnish what they represent, and that 
we become participants in the body and blood of Jesus Christ. 
Calvin, after having refuted those who content themselves with 
a metaphorical participation of thought or of seal and with a 
union of faith, adds that we can say nothing sufficiently strong 
to establish its reality, that he is not ready to subscribe to, pro- 
vided we avoid everything which looks to the circumscription 
of place or the diffusion of dimension ; so that it appears that 
at bottom his doctrine was that of Melanchthon and even of 
Luther (as Calvin himself conjectured in one of his letters), 
except that in addition to the condition of the perception of the 
symbols with which Luther contents himself, he demands also 
the condition of faith, in order to exclude the participation of 
the unworthy. I have found Calvin so positive upon this real 
communion in a hundred places in his works, and even in his 
familiar letters, where there was no need of being so, that I do 
not see any reason to suspect artifice. 






ch. «] ON HUMAN UNDERSTANDING 613 

S 11. Ph. [I ask your pardon if I have spoken of these gentle- 
men according to the common opinion. I remember now hav- 
ing remarked that some very clever theologians of the Anglican 
church have been for this real participation. But from estab- 
lished principles let us pass to the accepted hypotheses. Those 
who admit that they are only hypotheses often cease not to 
maintain them with warmth, almost as if assured principles, 
and to despise contrary probabilities. It would be unendurable 
to a learned professor to see his authority overturned in an 
instant by a new comer who should reject his hypotheses ; his 
authority, I say, which has been in vogue for thirty or forty 
years, acquired by much labor at night, sustained by much 
Greek and Latin, confirmed by a general tradition and by a 
venerable beard. All the arguments which we can employ to 
convince him of the falsity of his hypothesis will be as little 
capable of prevailing upon his mind as the efforts Boreas made 
to compel the traveller to leave his cloak, which he held so 
much the more firmly as the wind blew with more violence. 

Th. In reality the Copernicans have experienced in the case 
of their adversaries that hypotheses recognized as such ceased 
not to be maintained with an ardent zeal ; and the Cartesians 
are not less positive regarding their grooved particles and little 
balls of the second element l than if they were the theorems of 
Euclid ; and it seems that zeal for our hypotheses is merely a 
result of the passion we have of making ourselves respected. 
It is true that those who condemned Galileo believed that the 
rest of the earth was more than an hypothesis, for they judged 
it in conformity with Scripture and reason. But since then it 
has been perceived that reason at least sustained it no longer ; 
and as for Scripture, Father Fabry, Penitentiary of St. Peter, 
an excellent theologian and philosopher, publishing in Pome 
itself an Apology for the Observations of Eustachio Divini, 2 

1 Of. New Essays, Preface, ante, p. 51, line 11 ; Descartes, Princip. Philos., 
Pt. III., §§ 52, 90. The "grooved particles" and "little balls of the second 
element " are a part of the vortices-theory (cf. ante, p. 552, note 1). For the 
"matter of the first and second element" and the genesis of the "perfect 
globes " or " balls of the second element," cf. Princip. Philos., Pt. III., § 48 sq. 
The notes of J. H. von Kirchmann in his German trans, of this work of Des- 
cartes (Philos. Bibliothek., Vol. 26, 2d ed., Heidelberg, 1887) are a valuable 
aid in the study of the theory. — Tr. 

2 Eustachio Divini, c. 1620 — c. 1666, an Italian mechanician, optician, and 
astronomer, noted for his skill in making optical instruments, especially tel- 



614 LEIBNITZ'S CRITIQUE OE LOCKE [bk. iv 

a famous optician, hesitated not to declare that it was only pro- 
visionally that they understood in the sacred text a true move- 
ment of the sun, and that if the view of Copernicus were found 
true, there would be no difficulty in explaining it in like man- 
ner as this passage of Vergil : 

terraeque urbesque recedunt. 1 

However, they did not cease to continue in Italy and in Spain 
and even in the hereditary states of the emperor to suppress 
the doctrine of Copernicus, to the great detriment of these na- 
tions whose scholars might have raised themselves to more 
beautiful discoveries had they enjoyed a reasonable and philo- 
sophic liberty. 

, § 12. Ph. The dominant passions appear to be in reality, as 
you say, the source of the love we have for hypotheses : but 
they also extend very much farther. The greatest probability 
in the world will avail nothing in showing his injustice to an 
avaricious and ambitious man; and a lover will have every 
facility in the world for allowing himself to be duped by his 
mistress, so long as it is true that we easily believe whatever 
we wish, and according to the remark of Vergil, 

qui am ant ipsi sibi somnia fingunt. 2 

This is what makes them make use of two means of escaping 
the most apparent probabilities when they attack our passions 
and our prejudices. § 13. The first is to think that there may 
be some sophistry concealed in the argument which they oppose 
to us. § 14. The second in supposing that we might put before- 
hand wholly as good or even better arguments in order to beat 
the adversary, if we had the opportunity, or skill, or aid, which 

escopes, was the reputed author of a little work entitled Brevis annotatio in 
Systema Saturnium Christiani Hugenii [Hag. Corn., 1G59, 4to] , Rome, 1660, 
8vo, in which an attempt was made to refute Huygens' theory of the planet* 
Saturn. Divini, however, was no Latinist, and probably had little share in 
the hook, contributing merely "his pretended observation of the three sepa- 
rate bodies"; the real author was most likely the Jesuit, Honore Fabri (c/. 
ante, p. 586, note 2). Huygens reprinted the work together with his reply, 
Brevis assertio systematis Saturnii sui, Hag. Com., 1660; and Divini pub- 
lished his rejoinder, Septempedanus pro sua annotatione in syst. Saturn. Ch. 
Hugenii, adversum ejus assertionem, Rome, 1661. On the whole subject, cf. 
Huygens, CEuvres completes, La Haye, 1888-1893, 5 vols., passim. — Te. 

iJEn. 3, 72.— Te. 

2 Eclog. 8, 108.— Te. 



ch. xx] ON HUMAN UNDERSTANDING 615 

we must have to discover them. § 15. These means of shield- 
ing themselves from conviction are sometimes good, but they 
are also sophisms when the matter is sufficiently explained and 
everything has been taken into account; for after that there 
are means of knowing with regard to all upon what side the 
probability is found. Thus there is no room for doubting that 
the animals have been formed by the movements of an intelli- 
gent agent, rather than by a fortuitous concourse of atoms ; as 
there is no one who doubts in the least whether the characters 
of printing which form an intelligent discourse have been 
brought together by an attentive man, or by a confused medley. 
I should think then that it does not depend upon us to suspend 
our assent in these instances ; but we can give it when the 
probability is less evident, and we can even content ourselves 
with more feeble proofs which better agree with our inclina- 
tion. § 16. It appears to me impracticable for the truth for a 
man to lean to the side upon which he sees the less probability ; 
perception, knowledge and assent are not arbitrary, as it does 
not depend upon me to see or not to see the agreement of two 
ideas, when my spirit is turned toward them. We can how- 
ever voluntarily arrest the progress of our researches ; without 
this ignorance or error could not in any case be a sin. It is in 
this that we exercise our liberty. It is true that in the in- 
stances where we have no interests, we embrace the common 
opinion, or the view of the first coiner ; but in the points where 
our happiness or misery is concerned, the mind applies itself 
more seriously to weighing the probabilities, and I think that 
in this case, that is, when we are attentive, we have no choice 
in determining ourselves for the side we prefer, if between the 
two sides there are differences at once visible, and that it will 
be the greatest probability that will determine our assent. 
^.Th. I am of your opinion at bottom, and we have given 
sufficient explanation upon this matter in our preceding con- 
ferences when we spoke of liberty. I showed then that we 
never believe what we wish, but rather what we see is the most 
apparent ; and that nevertheless we can make ourselves believe 
indirectly what we wish by turning away the attention from a 
disagreeable object in order to apply ourselves to another which 
pleases us. This makes us in regarding more the reasons of 
a favorite side believe at last the more probable. As for the 



CIO LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

opinions in which we take little interest and which we receive 
upon slight reasons, we do this because, noticing scarcely any- 
thing which opposes them, we find that the opinion which 
makes us regard them favorably surpasses as much or more 
the opposite opinion, which has nothing in its behalf in our 
perception, as if it had had many reasons on both sides, for the 
difference between and 1, or between 2 and 3, is as great as 
between 9 and 10, and we perceive this advantage, without 
thinking of the examination which would still be necessary 
in order to judge, but to which nothing impels us. 

§ 17. Ph. The last false measure of probability that I in- 
tended to notice is improperly understood authority, which keeps 
more people in ignorance and error than all the others together. 
How many people we see who have no other basis for their 
views than the opinions received among our friends or among 
the members of our profession or of our party, or of our coun- 
try ! Such a doctrine has been approved by venerable antiq- 
xuty ; it comes to me under the passport of preceding centuries ; 
other men yield to it ; this is why I am shielded from error in 
receiving it. We have as much authority for tossing up in 
order to take these opinions, as to take them upon the basis of 
such rules. And besides the fact that all men are liable to 
error, I believe that if we could see the secret motives which 
actuate the scholars and chief men of a sect, we should find 
often something wholly different from the pure love of the 
truth. It is certain at least that there is no opinion so ab- 
surd that it cannot be embraced upon this basis, since there is 
scarcely an error which has not had its partisans. 

Tli. It must, however, be admitted that in many instances 
we cannot avoid yielding to authority. St. Augustine has pro- 
duced quite a remarkable book " De utilitate credendi," * which 
deserves to be read on this subject, and as for the received 
opinions, they have for themselves something approaching to 
that which gives what is called presumption with the juriscon- 
sults : and although we are not obliged to follow them always 
without proofs, we are no more authorized to destroy them in 
the mind of another without having contrary proofs. This it 
is which does not allow us to change anything without reason. 

1 Of. Opera, Benedictine ed., Vol. 8, pp. 45-70, Paris, 1688; Migne, Patrol, 
s. hat., Vol. 42 [Vol. 8 of Augustine], pp. 65-92. — Tr. 



en. xx] ON HUMAN UNDERSTANDING 617 

The argument drawn from the great number of the approvers 
of an opinion has been much disputed since the late M. Nicole 
published his book on the church ; l but all that may be drawn 
from this argument, when the question is of approving a reason 
and not of attesting a fact, may be reduced merely to what I 
have just said. And as one hundred horses do not run faster 
than one horse, though they can draw more, so it is with one 
hundred men as compared with one single man ; they cannot 
go more justly, but they will work more effectively; they can- 
not judge better, but they will be capable of furnishing more 
matter upon which the judgment may be exercised. This, is 
the meaning of the proverb : plus vident ocidi quam oculus. AVe 
notice it in the councils, where really a multitude of considera- 
tions are put upon the carpet which would perhaps escape one 
or two, but they run a risk often of not taking the better side 
in concluding upon all these considerations, when there are 
no skilful persons charged with directing and weighing them. 
Hence some judicious theologians of the Roman party, seeing 
that the authority of the church, i.e. that of the most exalted 
in dignity and the most supported by the multitude, could not 
be certain in a matter of reasoning, have reduced it to the mere 
attestation of the facts under the name of tradition. This was 
the opinion of Henry Holden, 2 an Englishman, doctor of the 
Sorbonne, author of a book entitled " Analysis of the Faith," 
in which, following the principles of the " Commonitorium " of 
Vincent de Lerins, 3 he maintained that we cannot make new 

i Cf. ante, p. 530, note 1. — Tr. 

2 Henry Holden, 1596-1662, was an English Roman Catholic divine, who 
graduated at the Sorbonne, and was appointed Professor of Theology there. 
In 1617 he petitioned the House of Commons for toleration of the Catholics, 
provided they would take the oath of allegiance. His Divinse Fidel Analysis, 
a concise exposition of the Catholic articles of faith as distinguished from 
matters of opinion, appeared at Paris, 1652, with an appendix consisting of a 
short treatise on Schism. It was reprinted at Paris, 1685, 1767, at Cologne, 
1655, 1782, Eng. trans., by " W. G.," 1658. Dupin, who gives a full abstract 
of the book in his Bibl. des Aut. eccles., 1711, torn. 17, pp. 191—203, considers 
him one of the ablest controversialists of his time. In 1656 he was engaged 
in a controversy with Antoine Arnauld, the Jansenist (cf. ante, p. 463, note 4), 
and his letters to Arnauld were printed in later editions of the Analysis. — Tr. 

3 St. Vincent of Lerins, of Gallic origin, who died about 450. His Adversus 
p?'ofanas omnium novitates Hxreticorum Commonitorium, written in 434, 
three years after the Council of Ephesus, energetically affirms the authority 
of tradition against all religious and doctrinal innovations. In chap. 2 of this 
short treatise occurs the famous threefold test of orthodoxy : ' ' Quod semper, 



618 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

decisions in the church, and that all the bishops assembled in 
council can do is to attest the fact of the doctrine received in 
their dioceses. "* The principle is specious so long as we continue 
in generalities ; but when we come to the fact, it is found that 
in different countries different opinions have been received for 
a long time ; and in the same countries also they have gone 
from one extreme to another, notwithstanding the arguments 
of Arnauld against insensible changes ; besides often without 
confining themselves to attest them, they have taken it upon 
themselves to judge. It is also at bottom the opinion of Gret- 
ser, 1 a learned Jesuit of Bavaria, author of another Analysis of 
Faith, approved by the theologians of his order, that the church 
may judge controversies by making new articles of faith, since 
the assistance of the Holy Spirit is promised it, although most 
frequently they try to disguise this view, especially, in France, 
as if the church were only to explain doctrines already estab- 
lished. But the explanation is a statement already received, 
or a new one which they believe may be drawn from the re- 
ceived doctrine. Practice is most frequently opposed to the 
first sense, and in the second, what can the new statement 
which is established be but a new article ? I am not, however, 
of the opinion that we despise antiquity in the matter of relig- 
ion; and I also believe that we may say that God has pre- 
served the truly ecumenical councils hitherto from all error 
contrary to wholesome doctrine. For the rest, sectarian prej- 
udice is a strange thing. I have seen people embrace with 
ardor an opinion for- the sole reason that it is received in their 
order, or even solely because it is contrary to that of a man of 
a religion or of a nation which they do not like, although the 

quod ubique, quod ab omnibus creditum est." The work has been edited by 
Baluze, Paris, 1663, 1669, 1684, Kliipfel, Vienna, 1809, Pusey, Oxford, 1838, 
Herzog, Breslau, 1839, and others; Eng. trans, by Flower, London, 1866. 
See also Migne, Patrol. Theol. cur. compl., Vol. 1, p. 911, Paris, 1846. A 
full account of it is given in Smith-Wace, Diet, of Christ. Biog., 4, 1154- 
1158. — Tr. 

1 Jac. Gretser, 1561-1625, a learned Jesuit, was Professor of Philosophy 
and various parts of Theology at Ingolstadt for twenty-four years. A man 
of immense erudition, and a voluminous author, he was lacking in taste and 
critical power, and was very harsh and bitter in discussion. It is said of him 
that, when asked by the magistrates of Marckdorf in Swabia, his birthplace, 
for his portrait to be placed in the town hall, he refused it, saying they had 
no place therein for the head of an ass. His complete works appeared at 
Ratisbonne, 1739 sq., 17 vols., fol. — Tr. 



ch. xx] ON HUMAN UNDERSTANDING 619 

question had almost no connection with the religion or the 
interests of the people. 1/ They did not know perhaps what was 
in reality the source of their zeal ; but I knew that, upon the 
first news that such an one had written this or that thing, they 
would ransack the libraries and puzzle their brains to find 
something to refute it. This it is which is practised so often 
by those who maintain theses in the universities and who seek 
to distinguish themselves against their adversaries. But what 
shall we say of the doctrines prescribed in the Symbolic books 
of the sect, even among 1 the Protestants, which we are often 
obliged to embrace with an oath ? which some think signi- 
fies with us only the obligation to profess what these books 
or formularies contain of Holy Scripture ; in which they are 
Contradicted by others. And in the religious orders of the 
Eoman party, without contenting themselves with the doctrines 
established in their church, they prescribe narrower limits to 
those who teach them ; witness the propositions the teaching 
of which in their schools the General of the Jesuits, Claudio 
Acquaviva 2 (if I am not mistaken), defends. "*It would be well 
(to mention it in passing) to make a systematic collection of 
the propositions determined and censured by councils, popes, 
bishops, superiors, faculties, which would be of use in ecclesi- 
astical history. We may distinguish between teaching and 
embracing an opinion. There is no oath in the world nor pro- 
hibition which can force a man to abide in the same opinion, 
for opinions are involuntary in themselves : but he may and 
should abstain from teaching a doctrine which is regarded as 
dangerous, unless he finds himself compelled thereto by his 
conscience. In this case he must declare himself sincerely and 
leave his post when he has been charged with teaching ; sup- 
posing, however, that he can do so without exposing himself 
to an extreme danger which might force him to leave without 

1 Gerhardt, Erdrnann, and Jacques read: "parmi" : Janet reads: "par," 
i.e. "by."— Tr. 

2 Claudius Aqua viva, 1543-1615, General of the Jesuits, 1581-1615. For a 
brief account of his Ratio Studiorum, 1599, cf. Hughes, Loyola and the Edu- 
cational System of the Jesuits, pp. Ill sq. (in The Great Educators Series, ed. 
by Nicolas Murray Butler), New York: Chas. Scribner's Sons, 1892. For the 
text of the Ratio, and a full account of its growth from its preliminary to its 
final form, with the letters of Aquaviva and other documents, cf. Monumenta 
Germanise, Psedagoqica, Berlin, A. Hofmann & Co., 1886 sq., Bd. V., Tom. II. 
— Tr. 



620 LEIBNITZ'S CRITIQUE OF LOCKE [bk. it 

fame. We see but little other means of reconciling the rights 
of the public and of the individual ; the one being under obli- 
gation to prevent what it judges bad, and the other not being 
able to dispense with the duties demanded by his conscience. 

J§ 18. Ph. This opposition between the public and the indi- 
vidual and even between the public opinions of different sects 
is an inevitable evil. But often these very oppositions are only 
apparent and consist only in the formulas. I am obliged also 
to say, in order to be just to the human race, that there are not 
so many people involved in error as is ordinarily supposed. 
Not that I think that they embrace the truth, but because in 
reality upon the doctrines upon which they make so much stir, 
they have absolutely no positive opinion, and because without 
having examined anything and without having in the mind the 
most superficial ideas upon the master in question, they are 
resolved to hold themselves fast to their party, as soldiers who 
do not examine the cause they defend : and if the life of a man 
shows that he has no sincere regard for religion, it is sufficient 
for him to have the hand and tongue ready to maintain the 
common opinion, in order to commend himself to those who can 
procure him support. 

Th. This justice which you render to the human race does 
not redound to its praise ; and men would be more excusable in 
following their opinions than in disguising them for the sake 
of their interests. Perhaps, however, there is more sincerity in 
their deeds than you seem to give any one to understand. For 
without any knowledge of a reason, they can perhaps attain to 
an implicit faith by submitting themselves in general and some- 
times blindly, but often in good faith, to the judgment of others 
whose authority they have once recognized. It is true that the 
interest they find therein contributes to this submission, but 
this does not prevent them at last from forming an opinion. 
They are contented in the Eoman church with this almost 
implicit faith, not perhaps having any article thereupon, due to 
the revelation which is judged absolutely fundamental thereto 
and which is considered as necessary necessitate medii, i.e. the 
belief of which is a condition absolutely necessary to salvation. 
And they are all necessitate prmcepti, by the necessity therein 
taught of obeying the church, as they call it, and of giving all 
attention to that which is proposed therein, all under pain of 



ch. xxi] ON HUMAN UNDERSTANDING 621 

mortal sin. But this necessity demands only a reasonable docil- 
ity and does not compel absolute assent, according to the most 
learned doctors of this church. Cardinal Bellarmine himself 
believed, however, that nothing was better than this faith of a 
child who submits himself to an established authority, and he 
relates with approval the statement of a dying man, who escaped 
the devil by this circle, which they heard him often repeat : 

I believe all that the church believes, 
The church believes what I believe. 



CHAPTER XXI 

OF THE DIVISION OF THE SCIENCES 

§ 1. Ph. Here we are at the end of our course, and all the 
operations of the understanding are explained. Our purpose is 
not to enter into the detail indeed of our knowledge, yet it will 
perhaps be proper here, before we conclude, to make a general 
review by considering the division of the sciences. All that 
can enter into the sphere of human understanding is either the 
nature of things in themselves, or in the second place, man in the 
character of an agent, tending towards his end and in particular 
towards his happiness, or in the third place the means of acquir- 
ing and communicating knowledge. Science then is divided 
into three kinds. § 2. The first is Physics or Natural Philoso- 
phy, which comprises not only bodies and their properties, as 
number, figure, but also spirits, God himself and the angels. 
§ 3. The second is Practical Philosophy or Ethics, which teaches 
the means of obtaining good and useful things, and proposes to 
itself not only the knowledge of the truth, but also the practice 
of that which is right. § 4. Finally, the third is Logic or the 
knowledge of signs, for Ao'yos signifies word. We need signs of 
our ideas to enable us to communicate our thoughts to one 
another, as well as to register them for our own use. Perhaps 
if we should consider distinctly and with all possible care that 
this last kind of science revolves about ideas and words, we 
should have a logic and criticism 1 different from that which has 

1 Locke has: "critic," Philos. Wks., Vol. 2, p. 338, Bonn's eel.; Fraser, 
Locke's Essay concerning Human Understanding, Vol. 2, p. 462. — Tr. 



622 LEIBNITZ'S CRITIQUE OF LOCKE [nit. iv 

hitherto been seen. And these three kinds, Physics, Ethics, 
and Logic, are like three great provinces in the intellectual 
world, entirely separate and distinct the one from the other. 

TJi. This division has already been a celebrated one among 
the ancients ; for under Logic they comprised, as you do, all 
that relates to words and to the explication of our thoughts : 
Artes dicendi. Nevertheless, there is some difficulty therein; 
for the science of reasoning, of judgment, of invention appears 
very different from the knowledge of the etymologies of words 
and the use of languages, which is something indefinite and 
arbitrary. Farther, in explaining words, we are obliged to make 
an incursion into the sciences themselves, as appears by the 
dictionaries ; and on the other hand, we cannot treat of science 
without giving at the same time definitions of the terms. But 
the principal difficulty found in this division of the sciences is 
that each part appears to absorb the whole ; in the first place, 
Ethics and Logic will fall into Physics, taken as generally as 
you have just stated; for in speaking of spirits, i.e. of sub- 
stances having understanding and will, and in explaining this 
understanding to the bottom, you will make it include all logic : 
and in explaining in the doctrine of spirits what belongs to the 
will, it would be necessary to speak of good and evil, of happi- 
ness and misery, and it will only depend upon you to push this 
doctrine far enough to make it include all practical philosophy. 
In return, all might be included in practical philosophy as serv- 
ing for our happiness. You know that Theology is rightly con- 
sidered as a practical science, and Jurisprudence as well as 
Medicine are not less so ; so that the doctrine of human happi- 
ness or of our good and ill will absorb all these branches of 
knowledge, should we desire to explain sufficiently all the means 
serving the end which reason proposes to itself. Thus it is 
that Zwinger has included all in his " Magnum theatrum vitse 
humani," which Beyerling has disturbed by arranging in alpha- 
betical order. 1 And in treating all matters in dictionaries fol- 

1 Laurent Beyerlinck, or Beierlynck, 1578-1627, a Flemish scholar, Professor 
of Poetry and Rhetoric at Vaulx, and Canon of the Antwerp Cathedral, pub- 
lished, with additions and corrections, the Theatrum vitx humanm of Zwinger 
(c/. ante, p. 548, note 1), with the title Magnum theatrum vitas, humanse, 
Cologne, 1631, 8 vols., fol. Schaarschmidt states that this new edition in 
alphabetical order is, in fact, worth less than the old redaction of the book, 
which handled the materials systematically in their essential aspects. — Tr. 



en. xxi] ON HUMAN UNDERSTANDING 623 

lowing the order of the alphabet, the doctrine of languages 
(which you with the ancients put in Logic), i.e. in discursive 
logic, takes possession in its turn of the territory of the two 
others. Here, then, your three great provinces of encyclopedia 
are in continual war, since one is always encroaching upon the 
rights of the others. The Nominalists believed that there were 
as many particular sciences as truths, 1 which they composed 
after the wholes according as they arranged them ; and others 
compare the entire body of our knowledge to an ocean, which 
is all of a piece and Yvdiich is divided into Caledonian, Atlantic, 
Ethiopic, Indian only by. arbitrary lines. ^It is usually found 
that one and the same truth may be put in different places, 
according to the terms it contains, and also according to the 
mediate terms or causes upon which it depends, and according 
to the inferences and results it may have. A simple categoric 
proposition has only two terms ; but a hypothetic proposition 
may have four, not to speak of complex statements. A remark- 
able history may perhaps be placed in the annals of universal 
history and in the history of the country where it happened, 
and in the history of the life of a man who was interested 
therein. And suppose the question therein concerns some fine 
precept of morals, some stratagem of war, some invention use- 
ful in the arts which serve the conveniences of life or the health 
of men, this same history will be related to some purpose in the 
science or art it concerns, and indeed it can be mentioned in 
two parts of this science, viz., — in the history of the discipline 
in order to recount its efficient growth, and also in the precepts 
to confirm them or illuminate them by examples. For example, 
what is very properly told in the life of Cardinal Ximenes, that 
a Moorish woman cured him by rubbings only of a hectic almost 
desperate, deserves also place in a system of medicine, as well 
in the chapter on hectic fever, as when the question concerns a 



1 The phrase " as many sciences as truths " — " tot esse scientias quot veri- 
tates " — is, as Schaarschraidt says, "the sharpest expression of nominalistic 
individualism." " According to Nominalism, we have a knowledge of partic- 
ulars only, all universals being merely figmenta mentis, products of abstrac- 
tion. Hence true and genuine science always relates to particulars only, and 
thus there are as many sciences as (particular) truths." 

On Leibnitz's studies of Nominalism, cf. Guhrauer, Leibnit. Dissertatio de 
princ. Individ., pp. 39 sq., Leibnitz, De stilo philos. Nizolii, § 28, Gerhardt, 
4, 157-158, Erdmann, 68-69. -Tr. 



624 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

medicinal diet comprising these exercises ; and this observation 
will serve also the better to discover the causes of this disease. 
But we might further speak of this in medicinal logic, where 
the question is about the art of discovering remedies, and in the 
history of medicine, in order to show how remedies have come 
to the knowledge of men, and that it is often by the aid of sim- 
ple empirics and even charlatans. Beverovicius, 1 in a remark- 
able book on ancient medicine, drawn wholly from authors not 
physicians, would have rendered his work still more useful, if 
he had passed down to modern authors. We see by this that 
one and the same truth may have many places according to the 
different relations it can have. Those who arrange a library 
very often do not know where to place certain books, being in 
suspense between two or three places equally suitable. But 
let us now speak only of general doctrines and put aside partic- 
ular facts, history and languages. I find two principal dispo- 
sitions of all doctrinal truths, each of which should have its 
deserts and which it would be well to unite. The one would 
be synthetic and theoretic, ranking truths according to the order 
of proofs, as the mathematicians do, so that each proposition 
would come after those on which it depends. The other dispo- 
sition would be analytic and practical, commencing with the end 
of' men, i.e. with the goods whose consummation is happiness, 
and seeking in order the means available for acquiring these 
goods or avoiding the contrary evils. These two methods have 
place in general encyclopedia, while some have practised them 
in particular sciences ; for geometry itself, treated synthetically 
by Euclid as a science, has been treated by some others as an 
art, and might nevertheless be treated demonstratively under 
this form, which would show indeed some invention ; as if some 

1 Jan van Beverwyck, — Latin Beverovicius, — 1594r-1647, a noted Dutch 
physician, who studied at Leyden, Caen, Paris, Montpelier and Padua, where 
he received his M. D., and on his return became Professor of Medicine at Dor- 
drecht and physician to the city, in which also he held several civil offices, 
among them that of burgomaster. He labored to simplify the methods of pre- 
scribing for disease. He published a number of books distinguished for purity 
of style and relation of facts, and which, adorned with copper-plates and with 
the verses of Jakob Cats, 1577-1660, one of the oldest and most popular Dutch 
poets, " made in his time much sensation and met with much approbation." 
Among them was the Idea medicinse veterum, Lugd. Bat., 1637, 12mo, here 
mentioned by Leibnitz. His entire works were published at Amsterdam, 
1651, etc. — Tk. 



ch. xxi] ON HUMAN UNDEKSTANDING G25 

one proposed to measure all kinds of plane figures, and begin- 
ning with rectilinears, reflected that they may be divided into 
triangles and that each triangle is half of a parallelogram, and 
that parallelograms can be reduced to rectangles whose measure 
is easy. But in writing the encyclopedia, following both these 
two dispositions together, we might take measures for references 
in order to avoid repetitions. To these two dispositions the third 
according to the terms should be joined, which in reality would 
be only a kind of index, either systematic, arranging the terms 
according to certain predicaments which would be common 
to all the notions, or alphabetical according to the languages 
received among scholars. Now this index would be necessary 
in order to find together all the propositions into which the 
term enters in a sufficiently remarkable manner ; for according 
to the two preceding ways, where the truths are arranged accord- 
ing to their origin or use, truths concerning one and the same 
term cannot be found together. For example, it was not per- 
mitted Euclid, when he was teaching how to find the half of an 
angle, to add the means of finding its third, because he would 
have been obliged to speak of the conic sections, knowledge of 
which he could not yet assume in this place. But the index 
may and should indicate the places where are found the impor- 
tant propositions which concern one and the same subject. And 
we still lack such an index in geometry, which would be of great 
use in facilitating indeed invention and in pushing the science, 
for it would relieve the memory and often spare us the trouble 
of seeking again that which has already been found. And these 
indices would further be of use for a much stronger reason in 
the other sciences, where the art of reasoning has less power, 
and would be above all extremely necessary in Medicine. But 
the art of making such indices would be no slight one. Now 
considering these three dispositions., I find it remarkable that 
they correspond to the ancient division, which you have renewed, 
which divides science or philosophy into theoretic, practical and 
discursive, or rather into Physics, Ethics, and Logic. For the 
synthetic disposition corresponds to the theoretic, the analytical 
to the practical, and that of the index according to the terms to 
logic : so that this ancient division does very well, provided we 
understand these dispositions as I have just explained, i.e. not 
as distinct sciences, but as different arrangements of the same 
2s 



626 LEIBNITZ'S CRITIQUE OF LOCKE [bk. iv 

truths as far as we judge it advisable to repeat them. There 
is also a civil division of the sciences according to the faculties 
and professions. We make use of it in the universities, and in 
the arrangements of libraries ; l and Draudius, 2 with his continuer 
Lipenius, 3 who have left us the amplest, but not the best cata- 
logue of books, instead of following the method of the Pandects 
of Gesner, 4 which is wholly systematic, have contented them- 
selves with the use of the great division of the materials (much 



1 For Leibnitz's sketch of a library classification and catalogue, cf. bis Idea 
Leibnitiana Bibliotheca. Publicse secundum classes scientiarum ordinandi, 
Dutens, 5, 209-214. Cf. also bis Representation a S. A. S. le Due de Wolfen- 
buttel,pour V encourager a Ventretien de saBibliotheque, ibid., 5, 207-208; tbe 
same, in German, Guhrauer, Leibnitz's Deutsche Schrift., 2, 470^72. — Tr. 

2 Georg Draud, 1573-1630 or 1635, a student at Marburg University and 
afterwards a proof-reader at Frankfort, Basle, and at tbe famous typography 
at Feyerabend, and minister of tbe gospel at Gros-Carbeu, Ortenberg and 
Dauernheim, was tbe first to attempt an extended systematic bibliography. 
His Blbliotheca classica sive catalogus officinalis, in quo singuli singularum 
facultatum ac professionum libri — secundum artes et ordine alphabetico 
recensentur, Fraukfort, 1611, was the most complete bibliography of printed 
books that had then appeared. A 2d ed., increased by all the books printed 
from 1611-1625 of which the editor had knowledge, appeared in 1625. — Tr. 

3 Martin Lipenius, 1630-1692, a learned German bibliographer, who studied 
at Witternberg, and was co-rector of the gymnasium at Halle, and of the acad- 
emy at Lubeck, and rector and professor in the gymnasium at Stettin. He 
published Bibliotheca reatis juridica, 1679, the most valuable of his series, 
edited with additions by F. W. Struve, in 1720, by G. A. Jenichen, 1709-1759, 
a jurist, philologian and historian, with corrections in 1736, and a supplement 
in two parts, 1742 ; also several subsequent editions with corrections and addi- 
tions ; Bibliotheca realis medica, 1679, philosophica, 1682, theologica, 1685. 
They were called realis because tbe books were listed in the alphabetical order 
of subjects and not under the names of their authors. — Tr. 

4 Conrad Gesner, 1516-1565, called the "German Pliny," because of his 
vast erudition, was Professor of Greek, 1537, at Lausanne, and of Physics and 
Natural History, 1541, at Zurich. He made " the first comprehensive attempt 
at a general encyclopedia of literature, constructed in the form of a catalogue " 
in his Bibliotheca universalis. The work contained the titles of all then known 
books, existent or lost, published or announced, in Hebrew, Greek and Latin, 
giving mider each important name a vast amount of bibliographical informa- 
tion and criticism, original and selected, and often some specimens of their 
style. The first vol., Zurich, 1545, is arranged alphabetically according to 
the authors' names; the second, entitled Pandectsa sive partitionum univer- 
salhun , lib. XXL., — totius philosophise et omnium bonarum artium atque stu- 
diorum locos communes et ordines universales sim.ul et particulars, — Zurich, 
1548, is arranged according to subjects and divided into 19 books, book 21, a 
theological encyclopedia, not being published till 1549, and book 20, the 
medical writings, never appearing because in the author's view too imperfect 
for publication. It was reprinted and greatly enlarged by Simler in 1574, and 
by J. J. Fries, Zurich, 1583. — Tr. 



ch. xxi] ON HUMAN UNDERSTANDING 627 

the same as the libraries) following the four faculties (as they 
are called) of theology, jurisprudence, medicine and philosophy, 
and have afterwards arranged the titles of each faculty accord- 
ing to the alphabetical order of the principal terms entering 
into the inscription of the books : this lightened the task of 
these authors, because they had no need to see the book or to 
understand the matter which the book treats, but it does not 
sufficiently serve others, at least it does not make references in 
the titles to others of parallel signification ; for not to speak of a 
number of mistakes they have made, we see that often one and 
the same thing is called by different names, as, for example, 
observationes juris, miscellanea, conjectanea, electa, semestria, 
probabilia, beneclicta, and a multitude of similar inscriptions ; 
such books of the jurisconsults signify only the miscellanies of 
the Roman Law. This is why the systematic disposition of the 
materials is without doubt the best, and we may join with it 
alphabetical indices very full according to the terms and the 
authors. The civil and received division, according to the four 
faculties, is not to be despised. Theology treats of eternal 
felicity and all that relates thereto, so far as it depends on the 
soul and the conscience ; it is like a jurisprudence which regards 
what is said to exist cle foro interno and employs invisible sub- 
stances and intelligences : Jurisprudence has for its object gov- 
ernment and the laws, whose end is the happiness of men so 
far as the external and sensible can contribute thereto ; but it 
regards principally only that which depends upon the nature 
of the spirit, and does not enter much farther into the detail of 
material things whose nature it assumes in order to employ 
them as means. Thus is it relieved at once of an important 
point which concerns the health, strength and perfection of the 
human body, the care of which is given to the faculty of Medi- 
cine. Some have believed with some reason that we might add 
to the others the Economic Faculty, which would contain the 
Mathematical and Mechanical Arts, and all that concerns the 
detail of the subsistence of men and of the conveniences of life, 
in which Agriculture and Architecture would be included. But 
we abandon to the faculty of Philosophy all which is not 
included in the three faculties which we call superior. We do 
this quite badly, for we do it without giving means to those 
who are of this fourth faculty for perfecting themselves by 



628 LEIBNITZ'S CRITIQUE OF LOCKE [jjk. iv 

practice as those can do who teach the other faculties. Thus 
the mathematics perhaps excepted, we consider the faculty of 
philosophy only as an introduction to the others. 1 This is why 
we wish the youth to learn history, and the arts of speaking 
and some rudiments of theology and natural jurisprudence, 
independent of divine and human laws, under the title of meta- 
physics or psychology, ethics and politics with a little of physics 
also, in order to serve as young physicians. This, then, is the 
civil division of the sciences following the bodies and profes- 
sions of the scholars who teach them, without speaking of the 
profession of those who work for the public otherwise than by 
their discourses and who ought to be directed by true scholars, 
if the limits of knowledge were well understood. And even in 
the more noble manual arts, knowledge has been very much 
bound up with performance, and might be more so. As in fact 
they are joined together in medicine, not only formerly among 
the ancients (where physicians were also surgeons and apothe- 
caries), but also to-day especially among the chemists. This 
alliance also of practice and theory finds itself at variance both 
among those who teach what are called exercises, as also among 
the painters, or sculptors and musicians, and among some other 
kinds of virtuosi. And if the principles of all these professions 
and arts, and even of the trades, were taught practically among 
the philosophers, or in some other faculty of scholars as they 
might be, these scholars would be truly the teachers of the 
human race. 2 But it would be necessary to change much of 



1 I.e. in the broader sense of the term in which it is equivalent to the 
Humanities, — artes liberates, — the liberal education, disciplinary, stimulative 
and cultural of the student's entire powers, which was considered until very 
recently, and is regarded even now by many of the deepest and farthest-sighted 
thinkers on education, as an essential precedent and preparation for all later 
special professional study. The custom of regarding the Faculty of Arts 
or Philosophy as introductory to that of Theology, Medicine and Jurispru- 
dence, goes back to the university curricula of the Middle Age, the Trivium 
and the Quadrivium, with their respective degrees of A.B. and A.M., which in 
their essential character and principles, with the necessary changes incident 
to an advancing civilization, have been, till within a short time at least, the 
controlling influence in shaping the curricula and methods of all modern col- 
legiate and university education. — Tr. 

2 On this, as on every subject he touched, Leibnitz utters a suggestive and 
stimulating thought, which has in recent times brought forth much fruit in 
the establishment and maintenance of technical and art schools of every kind. 
— Tr. 



en. xxi] ON HUMAN UNDERSTANDING 629 

the present state of things in literature and the education of the 
youth, and consequently of the government. And when I con- 
sider how much men have advanced in knowledge in the last 
century or two, and how easy it would be for them to go incom- 
parably farther in order to render themselves happier, I do not 
despair that a considerable improvement will come in a more 
tranquil period under some great prince whom God will be able 
to raise up for the good of the human race. 1 

1 Leibnitz constantly labored to secure the sympathy and active co-opera- 
tion of the " great princes " in the initiation and furtherance of learning, sci- 
ence, and the higher ideal interests of mankind in general, a conspicuous 
example of his success being that of the great reformatory genius of his time, 
Peter the Great of Russia. Their correspondence is found in Foucher de 
Careil, (Euvres de Leibniz, 7, 395-598. Of. also W. Guerrier, Leibniz in seinen 
Beziehungen zu Russland und Peter dem Grossen, St. Petersburg and Leip- 
zig, 1873 ; Foucher de Careil, Leibniz et Pierre le Grand, Paris, 1873. For a 
general account of 'his various efforts in this direction, cf. Fischer, Gesch. d. 
u. Philos., Vol. 2, Leibniz, 3d ed., 1889, pp. 211-249; and for a brief account, 
Merz, Leibniz (Blackwood's Philos. Class.), pp. 74-83. — Tr. 



APPENDIX 



LEIBNITZ TO JACOB THOMASIUS 1 

April 20-30, 1669 

[From the Latin] 

How much that yeS/xa of philosophical history of yours has made 
the mouths of all water cannot be told ; for it is apparent how much 
difference there is between mere enumerations of names and those 
profound views concerning the connections of opinions. And cer- 
tainly all acquainted with the subject that I hear speak of your essay 
(you know that I never flatter), unanimously affirm that from no 
one man can a complete body of philosophical history preferably be 
expected. Very many skilled in antiquity rather than in art have 
given us lives rather than opinions. You will give the history not of 
philosophers but of philosophy. They say in England that Joseph 
Glanvill's History of the growth of the sciences since Aristotle is in 
press. 2 But I think he will pursue for the most part the mathemati- 
cal, mechanical, and physical periods of this inquiry only, so I think 

1 Gerhardt, Leibniz, philos. Schrift.l, 15-27; Erdmann, 48-54 ; Dutens, 4, 
Pt. 1.7-19; Kortholt, Leibnit. epist. ad diversos, Lipsise, 1734-42,2, 121-142. 
Kortholt's text gives the piece as printed by Leibnitz in his edition of Nizo- 
lius, and differs considerably from that given by Gerhardt, which is the text 
followed in this translation. Cf. also, Gerhardt, Leibniz, philos. Schrift., 4, 
162-174. In this "impression," says Gerhardt, Einleitung, ibid., p. 9, note **, 
" the copy of the Royal Library at Hanover has been used, in which are found 
MS. notes of Leibnitz." — Tr. 

2 Joseph Glanvill, 1636-1680, Court Chaplain to Charles II., published his 
defence of the Royal Society of London, entitled Plus Ultra, or the Progress 
and Advancement of Knowledge since the days of Aristotle, in 1668. In his 
idea of causation Glanvill was a predecessor of Hume. His Scepsis scientifica, 
or Vanity of Dogmatising, London, 1665, edited by John Owen, 1885, and his 
Be incrementis scientiarum, London, 1670, attacked the Aristotelian and Car- 
tesian dogmatism. Though a thorough-going sceptic in the direction of the 
scholastic philosophy, he was opposed to the materialism of Hobbes. Some 
account of Glanvill's views will be found in Lecky, Rationalism in Europe, 
1, 129 sq. D. Appleton & Co., New York, 1876. — Tr. 

631 



632 LEIBNITZ'S CRITIQUE OF LOCKE 

he has forestalled you in nothing. But I wish that you would pro- 
duce a style and form for this more modern age and admonish our 
inconsiderate youth that neither everything nor nothing is to be attrib- 
uted to the restorers. Bagheminns 1 is not the only critic to whom you 
are indebted ; there are the Patricii, Telesii, Campanelhe, Bodini, 
Mzolii, Fracastorii, Cardanii, Galilaei, Verulamii, Gassendi, Hobbii, 
Cartesii, Bassones, Digbaei, Sennerti, Sperlingii, Derodones, Deusingii, 
and many other names among whom the cloak of philosophy is 
divided. 2 To remind the world of these will be a diversion for you, a 
profit to the public. 

Who does not assent to your estimate of Bagheminus? There is no 
skilful adjustment in hypotheses, 3 no logical sequence of reasons, but 
in a word strange notions ; certainly unless he has something to 
observe useful in special physics, he will better be silent. But 
Scaliger, Sennert, and Sperling, — for he acknowledged himself a pupil 
of this one also, — seem to me to be the parents of the opinion of that 
one concerning God, the primary matter of things, who think that 
forms are produced not from the passive power of matter, but 
from the active power of the efficient one. Wherefore the conclu- 
sion is that they believe that God produces creatures rather from his 
own active power, than from nothing by objective and as it were 
passive power. God therefore in their opinion produces things out of 
himself, and so will be the primary matter of things. But as to this 
you will more properly judge. 

As to Descartes and Clauberg, I think in brief with you that the 
disciple is clearer than the master. Nevertheless, I should venture 
again to affirm that hardly any one of the Cartesians have added any- 
thing to the discoveries of the master. Certainly Clauberg, Rgeus, 4 

1 Of. the letter of Jacob Thomasius to Leibnitz, October 2, 1668, Gerbardt, 
Leibniz, philos. Schrift.,1, 14; Kortbolt, Leibnit. JEpistolse ad diversos, 3, 
35: "Bagheminus ille, cujus negotium geritur, Scabinus est Stetinensis, et a 
nostra turn theologica, tum philosophica facilitate petiit philosophise suae nova? 
censuram. Theologi responderunt. A nobis nihil aliud repositnm illi est, 
quam disputatio mea, qure si in manus hominis pervenit, facile judicabit, quo 
in banc novitatem animo sinius." — Tr. 

2 For some account of the lives and philosophy of the persons whose names 
are here mentioned, cf. Lasswitz, Gesch. d. Atomistik; Stockl, Gesch. d. 
Philos. d. Mittelalters, III. [Vol. 4]. — Anton Deusing, 1612-1666 (not referred 
to in the works cited), was a German physician and Professor of Medicine at 
Groningen. He had an extended knowledge of philosophy, mathematics, and 
oriental languages, and published many works, among them, De vero syste- 
mate rnundi, dissertatio mathematica, qua Copernici systema mundi reforma- 
tur, etc., Amsterdam, Elzevir, 1643, 4to. — Tr. 

3 Erdmann reads : " hypothesibus ejus," i.e. his hypotheses. — Tr. 

4 Jean de Raey, date of birth unknown, died 1702, was Professor of Philoso- 
phy in the University of Leyden 1652-1668, and entered upon his Professorship 
at Amsterdam in January, 1669, with an Oratio de sapientia veterum. In his 



APPENDIX 633 



Spinoza, 1 Clerselier, 2 Heerbord, 3 Tobias Andrese, 4 Henry Regius, 5 have 
published nothing but paraphrases of their master. But I call those 
Cartesians only who follow the principles of Descartes, from which 
number those great men Bacon, Gassendi, Hobbes, Digby, Cornelius 
of Hogheland, 6 etc., whom the common people confound with the 

Clavis philosophise naturalis sen introductio ad naturse contemplationem 
AHstotelico-Cartesianam, 1654, 2d ed., 1677, he sought to improve and com- 
plete the doctrine of Aristotle through that of Descartes. He explained 
Erkenntnisslehre wholly after the manner of Aristotle; hut contested his 
assumption of the eternity of the world or the divine nature of the stars. He 
discussed mainly the nature of matter and the origin of motion, wholly on a 
Cartesian hasis. — Tr. 

1 In the impression of this letter given hy Gerhardt, Leibniz, philos. 
Schrift., 4, 162 sq., Leibnitz has erased the names of Spinoza and Cornelius 
van Hooghelande, and added after Bacon that of Galileo. This impression 
omits also the names of Raeus and Clerselier. For the other textual changes, 
c/. the impression itself. — Tr. 

2 Claude Clerselier, 1614-1684, the father-in-law of Robault (cf. ante, p. 233, 
n. 2), was a zealous disciple of Descartes and edited some of his works: Le 
monde, ou traite de la lumiere, Paris, 1677; Traite de I'homme, Paris, 1664; 
Les lettres de Rene Descartes, 3 vols., Paris, 1657-1667. — Tr. 

3 Adrian Heereboord, 1614-1659, Professor of Philosophy in the University 
of Leyden, was one of the first and most zealous advocates of the new ten- 
dency of thought introduced by the philosophy of Descartes. He united to a 
certain extent Cartesianism with the traditional authority of Aristotle, evi- 
dence of which appears in his P arallelismus Aristotelicse et Cartesianse phi- 
losophise, naturalis, 1643. Other writings of Heereboord are: Meletemata 
philosophica, 1654; Philosophia rationalis, moralis, et naturalis, 1654, 2d ed., 
1660 ; Philosophia pneumatica, 1(559. — Tr. 

4 Tobias Andrew, 1604-1674, Professor of History and Greek Language at 
Groningen, successfully cultivated philosophy and became known as a zealous 
partisan of the philosophy of Descartes. He wrote, in 1653, against Jacob 
Revius, Assertio methodi Cartesianse, and was also author of Brevis expli- 
cate, brevi explicatione mentis humanse Henr. Regii ?-eposita. — Tr. 

5 Hendrik van Roy, 1598-1679, usually called Regius, was a Dutch physician, 
who in 1638 became Professor of Botany and Theoretical Medicine at Utrecht. 
He was a zealous disciple and advocate of the ideas of Descartes, until the 
Voet-Schoock-Descartes controversy and Descartes' rejection of him as a true 
representative of his views resulted in their falling out. Regius regarded the 
soul as a mode of the bodily substance, and in physics, while resting through- 
out on Cartesian principles, differed from Descartes in his conception of 
motion and rest. On this doctrine of Regius, significant for the problem of 
body, cf. Lasswitz, Gesch. d. Atomistik, 2, 405-408. Regius published, among 
other works, Fundamenta physicse, Leyden, 1646; Philosophia naturalis, 
Amsterdam, 1661. Dr. James Martineau, A Study of Spinoza, London, 
Macmillan & Co., 1882, page 75, line 7, and foot-note 1, in translating " Regis " 
instead of "Regius" has misunderstood Leibnitz's reference and wrongly 
attributed to him a " lapsus memorise." — Tr. 

6 Cornelius Van Hooghelande, a Catholic nobleman who lived at Leyden, 
was a friend and disciple of Descartes. In his Cogltationes, 1646, Hooghelande 
" so developed the fundamental doctrines of Descartes that the only Cartesian- 



634 LEIBNITZ'S CRITIQUE OF LOCKE 

Cartesians, must in a word be left out, since however they were either 
the equals or even the superiors of Descartes in age and natural 
capacities ; I acknowledge that I am anything but a Cartesian. 
That rule I hold common to all these renovators of philosophy, that 
nothing is to be explained in bodies except by magnitude, figure, and 
motion. In respect to Descartes I hold the argument only of his 
method, for when we come to the present matter, he relaxed utterly 
from that severity, and descended abruptly to certain extraordinary 
hypotheses, a course which in his case Vossius rightly indeed repre- 
hended in his book on Light. 

Wherefore I do not hesitate to say that I approve more things 
in the books of Aristotle irepi (jivcriKrj^ aKpodosws, than in the Medi- 
tations of Descartes ; so far am I from being a Cartesian. Nay more, I 
would venture to add that all those eight books can be received with- 
out violation of the reformed philosophy. By which very method 
those difficulties will ipso facto be met which you, most distinguished 
man, are investigating in regard to the irreconcilable Aristotle. 
For the conclusions of Aristotle concerning matter, form, privation, 
nature, place, infinity, time, motion, are for the most part certain and 
demonstrated, this one thing generally excepted, what he asserted 
about the impossibility of a vacuum and motion in a vacuum. For 
to me neither vacuum nor plenum is necessary, and the nature 
of things seems capable of explanation by either method. In behalf 
of the vacuum contend Gilbert, Gassendi, Gericke ; for the plenum, 
Descartes, Digby, Thomas Anglus, 1 Clerk 2 in his book " De plenitu- 
dine mundi." For the possibility of each, Thomas Hobbes and Robert 
Boyle. And I confess that, with difficulty indeed, yet without a 
vacuum, the. rarefactions of things can be explained. I saw recently 
the book of John Baptist du Haniel, 3 a French scholar, on the 

ism of his work was the dedication." Descartes regarded him, says Kuno 
Fischer, Descartes and his School, translated by Gordy, p. 503, " as a well- 
disposed man without a calling to philosophy, and without understanding his 
doctrine. " Cousin, OEuvres de Descartes, 6, 279-281, gives a letter, with a 
foot-note of an unknown editor stating his belief that Descartes wrote this 
letter to Van Hooghelande in March, 1636, at Amsterdam. — Tr. 

1 Thomas White, 1582-1676, called Anglus, Albius, Candidus, etc., published 
his Institutionum Peripateticarum ad mentem summi clarissimique Philoso- 
phi Kenelmi Equitis Digbsei at Lyons, 1646. Leibnitz refers to him briefly 
in the Theoria motus concreti, § 55 (Gerhardt, Leibniz, philos. Schrift., 4, 
207; Math. Schrift., II., 2 [Vol. 6], 47), and in the Theoria motus abstracti 
{ibid., 4,228; II., 2 [Vol. 6], 67), as " subtilissimus"and " acutissimus." — Te. 

2 Gilbert Clerke, 1626-1697 ?, a mathematician and theological writer, in his 
first work, De Pleniiudine Mundi, etc., 1660, reviewed Descartes and attacked 
Bacon and Hobbes, and published in 1662 his Tractatus de Restitutione Cor- 
porum, results of studies following Torricelli and Boyle. — Tr. 

3 Jean Baptiste du Hamel, 1624-1706, was a French experimental philoso- 
pher and astronomer, who lectured on physics and experimented so far as his 



APPENDIX 635 



harmony of ancient and modern philosophy, published not long 
since at Paris, in which he elegantly expounds and often acutely 
estimates the hypotheses of some of the most celebrated ancients 
and moderns. He also has not a few words concerning the con- 
flicting views about the vacuum. As to the rest, scarcely any sane 
man will call in question all the remaining things discussed by 
Aristotle in Bk. VIII. Phys. and the entire Metaphysics, Logic, 
and Ethics. Who does not admit the substantial form also; namely, 
that by which the substance of one body differs from the substance 
of another body? Nothing is truer than primary matter. This one 
thing is in question, whether the abstract discussions of Aristotle con- 
cerning matter, form, and change, are to be explained by magnitude, 
figure, and motion. The Scholastics deny, the Reformers affirm, it. 
The opinion of the Reformers seems to me not only the truer, but the 
more in harmony with that of Aristotle ; I will speak briefly of each. 
And first of Aristotle. For -that the Scholastics strangely ' pre- 
verted his meaning, to whom is it better known than to you, 
most distinguished man, who have been the first to bring forth 
into the light a good many of this class of errors? Since with 
you in metaphysics Soner x and Dreier,' 2 in logic Viottus, Zabarella, 3 

position and the instruments then existing allowed. He published, among 
other works, Astronomia physica, and De meteoribus et fossilibus, Paris, 
1660; De consensu veteris et novx philosophise, Paris, 1663 and later editions, 
the work here referred to by Leibnitz ; De corporum affectionibus, 1670 ; his 
Opera, Norimberga, 1681. Cf. Lasswitz, Gesch. d. Atomistik, 2, 493, 494. — Tr. 

1 Ernst Soner, 1572-1612, was Professor of Philosophy and Medicine at 
Altdorf, and in philosophy an Aristotelian. He was the author of many 
Disputationes, the greater part of which appeared in Felwinger's Philosophia 
Altdorfiana, Norimberga, 1644; also of Commentaries on Aristotle's Meta- 
physics and Physics, 1607; he also wrote against eternal punishment in his 
Demonstrationes quid seterna impiorum supplicia non arguant Dei justitiam 
sedinjustitiam, and some medical works. Cf. Magn. Dan. Omeisius, Gloria 
Academise Altdorfianse, etc., Altdorf, 1683. Leibnitz in his Preliminary 
Dissertatioyi to his edition of Nizolius (Gerhardt, 4, 155; Erdmann, 68 a; 
Dutens, 4, Pt. I., 57) speaks of his contribution, together with that of Dreier, 
to the understanding of Aristotle's Metaphysics ; and in the Theodicee, Pt. III., 
§ 266, of his argument against eternal punishment. — Tr. 

2 Christian, or Peter, Dreier, 1610-1688, was Professor of Theology at Kon- 
igsberg, and published his Sapientia seu Philosophia prima, ex Aristotele 
ejusque optimis comment atoribus, conscripta, Konigsberg, 1644, 4to. Leibnitz 
refers to him in his Preliminary Dissertation to Nizolius (Gerhardt, 4, 155 ; 
Erdmann, 68 a; Dutens, 4, Pt. I. 57) and also in the Theodicie, Pt. II., § 184: 
"M. Dreier de Konigsberg a bien remarque que la vraie metaphysique 
qu'Aristote cherchait, et qu'il appelait ■»V C,r\Tov\i.ivr\v, son desideratum, etait 
la theologie." — Tr. 

3 Jacopo Zabarella, 1533-1589, was a teacher of Logic at Padua. His De rebus 
naturalibus, lib. XXX., appeared at Col., 1590, fob; his Opera logica, Col., 
1597, fol. ; both also in several later editions. An account of Zabarella will be 
found in Stockl, Gesch. d. Philos. d. Mittelalters, III. [Vol. 4], 263-272.— Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Jung, 1 in civics Jason Denores,' 2 Piccart, 3 Coming, Felden, 4 Durrius, 5 
and many others, acknowledge this, why, I pray, shall we not suspect 
the same or worse in physics, aids in the knowledge of which must be 
sought from sense and experiment, of which means the Scholastics 
confined for the most part in closed monasteries were absolutely 
deprived ? It is probable enough, therefore, that in physics they were 
deceived ; how if I shall show more than this, that it is altogether 
certain ? In which thing I may be engaged again in a twofold way. 
For either it is shown that the Reformed Philosophy can be recon- 
ciled with the Aristotelian and is not contrary to it, or further, it 
is shown that the one not only can, but also must, be explained by the 
other; nay, rather, that the very things which are discussed with 
so much pomp by the moderns flow from the Aristotelian principles. 
By the former way the possibility, by the latter the necessity, of the 
reconciliation is accomplished, although in this very instance if 
a possible reconciliation is shown, the thing is accomplished. For 

1 Joachim Jung, 1587-1657, an eminent mathematician and physicist, and 
an earnest advocate of the corpuscular theory, published Logica Hamburg- 
ensis, Hamburg, 1638, 8vo ; et recensente Joh. Vegetio, 1681, 8vo ; and various 
disputations. Leibnitz refers to his Geometria empirica, Hamburg, 1681, 8vo, 
in the Theodice'e, Pt. II., § 214. For an account of him and his corpuscular the- 
ory, cf. Lasswitz, Gesch. d. Atomistik, 2, 245-261; E. Wohlwill, J. Jungius 
und die Emeurwig atomistischer Lehren im 17 Jahrhundert, Hamburg, 1887 ; 
G. E. Guhrauer, J. Jung und sein Zeitalter, Stuttgart u. Tubingen, 1859. — Tr. 

2 Jason Denores, died 1590, was well acquainted with the peripatetic phi- 
losophy, and published Dell' ottima republica, Venice, 1578, 4to ; and De con- 
stitution^ philos. Aristotelis, Patavii, 1584, 4to. — Tr. 

3 Michael Piccart, 1574-1620, Professor of Philosophy and Poetry at Altdorf , 
was one of the most learned men of his times, and especially distinguished as 
an interpreter of Aristotle. Among his works were Isagoge in lectionem 
Aristotelis, Nuremberg, 1605, 8vo, reprinted with the notes of J. C. Durrius, 
Altdorf, 1660, 1666, 8vo; Organum Aristotelicum in qusest. et respons. redac- 
tion, Leipzig, 1613, 8vo ; In politicos libros Aristotelis, Leipzig, 1615, 8vo, Jena, 
1659, 8vo, a highly esteemed work, which was reprinted with the title: Argu- 
m,enta librorum politicorum Aristotelis, cum prsefatione de nsevis istius operis 
Aristotelici, Helmstadt, 1715, 4to. Cf. Morhof, Polyhistoria, 2, 63. —Tr. 

4 Johannes Felden, a jurisconsult, lived during the seventeenth century. 
Leibnitz refers to him in his Prelim. Dissert, to Nizolius (Gerhardt, 4, 155- 
156 ; Erdmann, 67 b, 68 a ; Dutens, 4, Pt. I., 57, 58), as the author of eruditis- 
simse . . . meditationes on the Topics and Analytics of Aristotle, "not yet 
published," of notes on Grotius, of Elementa Juris universalis, and Analysis 
Politicorum Aristotelis. Cf., also, Morhof, Polyhistoria, 2, 559. — Tr. 

5 Johann Conrad Durrius, 1625-1677, was Professor of Theology and Moral 
Philosophy at Altdorf. Among his writings were Compendium theologix 
moralis, in several editions, one of the best being that of 1698, 4to ; Oratio 
adversus Spinozam, Jena, 1672 ; Notse in Isagogen Piccarti, perhaps the work 
Leibnitz here had in mind in referring to Durrius. Morhof, Polyhistoria, 2, 
63, gives some account of an edition of Piccart's Isagoge in lectionem Aristo- 
telis, by Durrius, which appeared at Altdorf, 1665, 8vo. — Tr. 



APPENDIX 637 

although each explanation, both of the Scholastics and of the 
moderns, were possible, nevertheless from two possible hypotheses 
must always be chosen the clearer and more intelligible, such as 
indisputably is the hypothesis of the moderns, which makes for itself 
no incorporeal entities in the midst of bodies, but besides magnitude, 
figure, and motion assumes nothing. What possibility there is 
of reconciliation I cannot better show than by asking that some 
principle of Aristotle be given me which cannot be explained by 
magnitude, figure, and motion. 

Primary matter is the mass itself, in which there is nothing else 
than extension and avTirvma or impenetrability; it has extension 
from the space which it fills; the nature itself of matter consists 
in this, that it is something crass and impenetrable, and consequently 
movable when another meets it (while the second must yield). JSTow 
this continuous mass filling the world, while all its parts are at rest, is 
primary matter, from which all things are produced through motion, 
and into which they are resolved through rest. For there is in 
it no diversity, mere homogeneity, except through motion. Hence 
already all the difficulties of the Scholastics are solved. First, they 
inquire concerning its entitative character previous to all form. And 
the reply must be that it is an entity previous to all form, since it has 
its own existence. For all that exists, which is in any space, a fact 
which cannot be denied of that entire mass although without motion 
and discontinuity. But the essence of matter or the form itself of 
corporeity consists in avrnvirla or impenetrability ; matter also has 
quantity, but interminate, as the Averroists say, or indefinite; for 
while it is continuous, it is not cut into parts, and therefore no 
termini are actually given in it : yet extension or quantity is given. 
All things not concerning the extrinsic termini of the world, or 
the entire mass, but concerning the intrinsic termini of the parts, 
harmonize in a wonderful manner. 

From matter let us pass to form through the dispositions. Here 
again, if we assume form to be nothing else than figure, all things 
wonderfully accord. For since figure is the terminus of body, to 
introduce figures into matter there will be need of a terminus. 
In order, therefore, that various termini may arise in matter, there 
is need of a discontinuity of parts. For while for this very reason 
the parts are discontinuous, any one you please has separate termini 
(for Aristotle defines continua wv to. lo^aTa ev) ; but discontinuity can 
be induced in that mass before continuous in two ways ; in one way 
so that at the same time contiguity is destroyed, which happens 
when they are so violently separated from one another that a 
vacuum is left, or so that contiguity remains, which happens when 
those which are immediate to themselves remain, yet are moved in 
different directions ; for example, two spheres, one of which includes 



LEIBNITZ'S CKITIQUE OF LOCKE 



the other, can be moved in different directions, and yet remain con- 
tiguous, although they cease to be continuous. From these con- 
siderations it is evident that, if indeed from the beginning a mass 
discontinuous or broken up by vacuities was created, some forms 
of matter are at once concrete ; but if, indeed, it is continuous from 
the beginning, forms must of necessity arise through motion (for 
concerning the annihilation of certain parts in order to obtain vacui- 
ties in matter, because it is beyond nature I do not speak, because 
from motion division, from division termini of parts, from termini 
of parts their figures, from figure forms, therefore from motion 
forms arise). From which it is evident that all disposition to form 
is motion, evident also the solution of the vexed question concern- 
ing the origin of forms. Which question the distinguished man 
Herm. Conring could satisfactorily answer by his special disserta- 
tion only by asserting that forms arise from nothing. 1 We shall 
say they arise from the power of matter, not by producing any- 
thing new, but only by destroying the old, and causing termini by 
division of the parts, as he who makes a column does nothing else 
than 2 remove the useless parts, the residuum after the other parts 
are removed by this very means receiving that figure which we call 
a column ; that is to say, all the figures or forms which are contained 
in the mass itself need only determination and actual separation 
from the others adhering to them. If this explication is admitted, 
whatever arguments are produced against the origin of forms from 
the power of matter are mere trifles. 

It now remains for us to come to changes. Changes are enum- 
erated commonly and rightly: generation, corruption, increase, 
diminution, alteration, and local change or motion. The moderns 
think all these can be explained through local motion alone. And 
first, From increase and diminution the thing is manifest ; for a 
change of quantity in the whole takes place when a part changes 
its place, and either approaches or departs. It remains for us to 
explain generation and corruption and alteration through motion, 
and I note beforehand that the same numerical change is a gen- 
eration and alteration of different things, for example, since it is 
evident that putrefaction consists in those worms imperceptible to 

1 Gerhardt reads : " Conringius peculiari dissertatione non aliter satisfacere 
potuit, quam formas ex nihilo oriri." Erdmann reads : " Conringius peculiari 
dissertatione non aliter occurrit, quam concedendo formas ex nihilo oriri, sed 
meditationes istae compendiosiorem viam monstrant, ut illuc confugere necesse 
non sit. Discimus enim formas oriri," etc.; i.e., Conring met in Ms special 
dissertation not otherwise than by admitting that forms spring from nothing, 
but these very meditations show a more advantageous way, so that it is not 
necessary to flee thither. For we say that forms arise, etc. 

2 Erdmann and Dutens read : " quam quod inutilia tollit," i.e., than that 
which removes the useless parts. — Tr, 



APPENDIX 



the naked eye, any putrid infection will be an alteration of the 
man, a generation of the worm. In a similar way Hooke x shows 
in his " Micrographia," that rust in iron is a minute little forest 
(sylvulam) which has sprung up ; to rust therefore will be an alter- 
ation of the iron, a generation of little shrubs. But both genera- 
tion and corruption, as well as alteration, can be explained by a 
minute motion of parts; for example, since white is that which 
reflects the most light, black that which reflects little, those things 
will be white whose surface contains the largest number of little 
specula; this is the reason why foaming water is white, because it 
consists of innumerable little bubbles; moreover as many bubbles, 
so many specula, since before well-nigh the entire water was nothing 
but one speculum, as in a broken glass mirror (speculum), so many 
pai'ts become so many mirrors (specula) : which, indeed, is the reason 
why ground glass is whiter than that which is whole. In a simi- 
lar manner, therefore, when water is broken by bubbles into separate 
specula, whiteness arises, which is the reason also why snow is 
whiter than ice, and ice than water. For it is false that snow is 
condensed water, since it is rarefied rather, whence also it is lighter 
than water and occupies more space. By which reasoning the 
sophism of Anaxagoras concerning black snow is explained (diluitur). 
From these considerations it is evident that colors arise from change 
alone of figure and position in the surface ; the same explanation as 
regards light, heat, and all qualities, if occasion should allow, could 
easily be given. But now, if qualities are changed through motion 
alone, by the same process also substance will be changed : for if 
all, nay even if some, of the necessary qualities are changed, the 
thing itself is destroyed; for example, if you destroy either the 
light or heat, you will destroy the fire. And if the motion is set 
in operation (inhibito), you will produce each. And this is the 
reason why a closed fire dies for want of the nourishing air, so 
that I may pass over in silence the fact that the essence differs 

1 Robert Hooke, 1635-1703, Professor of Geometry in Gresham College, Ox- 
ford, and Secretary of the Royal Society, published his Micrographia, or 
some Physiological Descriptio?is of Minute Bodies in 1665. This book " con- 
tained the earliest investigation of the ' fantastical colours of ' thin plates, 
with a quasi-explanation by interference, the first notice of the ' black spot ' 
in soap-bubbles, and a theory of light, as 'a very short vibrative motion' 
transverse to straight lines of propagation through a ' homogeneous medium.' 
Heat was defined as ' a property of a body arising from the motion or agita- 
tion of its parts.' " From his paper (May, 1666) on curvilinear motion, illus- 
trated with the aid of the " circular pendulum," showing experimentally that 
the centre of gravity of the earth and moon is the point describing an ellipse 
around the sun, dates "the clear statement of the planetary movements as a 
problem in mechanics." For an account of his Vibration-theory, cf. Lasswitz, 
Gesch. d. Atomistik, 2, 329-338. An abridgment of his Micrographia appeared 
at London, 1780. — Tr. 



640 LEIBNITZ'S CKITIQUE OF LOCKE 

from its own qualities only in relation to the sense. For as the 
same city presents another aspect of itself, if you look down from 
a tower in the midst of the city (in Grund gelegt), which is just 
the same as if you beheld its essence ; it appears otherwise if 
you approach from without, which is just the same as if you per- 
ceive the qualities of the body; and as the external aspect of the 
city varies, according as you depart from the eastern or the west- 
ern side, so in a similar way the qualities vary in proportion to the 
variety of the organs. From these considerations now it is easily 
manifest that all changes can be explained through motion. It is no 
objection that generation takes place in an instant, that motion is 
successive, for generation is not motion but the end of motion ; 
therefore the end of motion is in an instant, for some figure is 
produced or generated by the very last instant of motion, as the 
circle is produced by the very last moment of the circumgyration. 
From these considerations it is evident why the substantial form 
consists in the indivisible, and does not receive more or less. For 
figure also does not receive more or less. For although one circle 
may be greater than another, yet the one circle is not more a circle 
than the other, for the essence of the circle consists in the equality 
of the lines drawn from the centre to the circumference; now 
equality consists in the indivisible and does not receive more or 
less. Nor, indeed, must the figure or the magnitude of the object 
be accidents, nor in fact are they always accidents ; for although, 
for example, flowing is an accident of lead, for it flows not unless 
in the fire, it is nevertheless of the essence of mercury. Now 
the cause of flowing is without doubt the free curvilineity of 
the parts, whether it consists of globes or cylinders or ovals or 
other spheroids : the curvilineity therefore of the subtile parts is 
an accident of the lead, but essential to the mercury. The reason 
is, because all metals arise from fixed mercury by means of the 
salts, and the nature of the salts consists in rectilinear figures fitted 
for rest; hence, if we allow salts dissolved in water to crystallize 
freely, some forms known to the chemists as tetraedric, others as 
hexaedric, octaedric, etc., but none round or curvilinear, appear. 
Hence salts are the cause of fixity ; therefore those acid salts mixed 
with the mercury in the bowels of the earth, as it were, through 
the smallest parts impede the freedom of the curvilinear parts 
by their interposition and constitute the metal. But in the fire 
the metal returns to the nature of mercury, for the fire interposing 
itself in the subtile parts, frees the curvilinear hydrargyrate parts 
from the plane-sided salts; hence the flowing in the fire. Thus 
it is evident that there is scarcely anything in the Aristotelian 
physics which cannot be properly explained and illustrated by the 
reformed. 



APPENDIX 641 



These examples, indeed, have occurred to me spontaneously (de 
med), while writing ; very many more are collected by others through 
all natural philosophy. Nor do I fear that in what I have hitherto 
said, you will think that I have followed too much the descriptions 
of Rseus or his authority. I was acquainted with such things 
some time before I even heard of Rseus. I read Rseus, to be sure, 
but in such a way that I now scarcely remember what subjects 
he discussed. Nor, indeed, was Rseus the first and only one of those 
promoting a union between Aristotle and the moderns. Scaliger 
seems to me to have been the first to pave the way; in our times 
Kenelm Digby and his follower, Thomas Anglus, the latter in his 
book on the immortality of the soul, the former in his " Peripatetic 
Institutions," treated ex professo the same subject long before Rseus. 
Nor do both Abdias Trew 1 and especially Erhard Weigel differ 
from them. Hitherto we have shown the possibility only of recon- 
ciliation ; it remains for us to' show the necessity also. Of what 
else, namely, does Aristotle in the eight books of the " Phys. Auditus " 
treat than figure, magnitude, motion, place, time? If therefore the 
nature of body in general is completed (absolvitur) by these, the 
nature of body in particular will be completed by a given figure, 
a given magnitude, etc. And, indeed, he himself says, Book 3, 
chapter (text.) 24, Phys., that all natural science is concerned with 
magnitude (with which figure is connected), motion, and time. 
Aristotle often says the same, that movable being is the subject of 
physics, that natural science treats of matter and motion ; he himself 
also makes heaven the cause of all things which take place in the 
sublunary worlds. Now heaven, he says, does not act upon the 
bodies below it except through motion. But motion does not 
produce anything but motion or termini of motion, namely magni- 
tude and figure, and from these the resulting position, distance, 
number, etc. From these, therefore, everything in nature must be 
explained. The same Aristotle likewise often says (as Book I. 
of the "Phys. Aud.," chap. 69) that the relation of the brass to the 
figure of the statue is the same as that of the matter to the form. 
But I might prove that the figure is the substance, or rather that the 

1 Abdias Trew, 1597-1669, was Professor of Physics and Astronomy in the 
University of Altdorf , where he erected, 1657, the first observatory seen in 
that part of the world. He made discoveries in the theory of music, espe- 
cially as regards the most accurate temperament, which he set forth in his 
Janitor lycxl musici, Rothenburg, o. T., 1635. His chief work was in astron- 
omy and meteorology, and he carefully observed all the comets appearing 
during his lifetime. As a chronologer he contributed to the adoption of the 
Gregorian calendar by the Protestant states. He published, among other 
works, Directorium mathematicum, Nuremberg, 1657 ; Lehrbuch d. sphdri- 
schen Astronomie, Nuremberg, 1637; Griindliche Calendarkunst, Liineberg, 
1666. — Tk. 

2t 



642 LEIBNITZ'S CRITIQUE OF LOCKE 

space is the substance, that the figure is something substantial, because 
all science is concerned with substance ; further it cannot be denied 
that geometry is a science. You replied that you could produce the 
place in which Aristotle had denied that geometry was a science 
sooner than I would produce that in which he affirmed it. I do not 
indeed doubt, illustrious sir, that there are some places of Aristotle 
which can be drawn or twisted to this purpose, but yet I think that 
these are overthrown by a very large number of his other expressions. 
For what is more frequent in all the books of the " Analytics " 
than examples of geometers, so that he seems to have wished 
geometrical demonstrations to be, as it were, the measure of the rest. 
Now the more ignoble is absurdly constituted the measure of the 
more noble. And so meanly, indeed, did the Scholastics think of 
mathematics at first, that they made every effort to exclude mathe- 
matics from the number of the perfect sciences, principally by means 
of this argument, because it does not always demonstrate from causes. 
But if we consider the matter more accurately, it will apjDear that 
it does demonstrate from causes. For it demonstrates figures from 
motion : from the motion of the point is produced the line, from the 
motion of the line the surface, from the motion of the surface the 
body. From the motion of the right line upon right lines arises 
the rectangle. From the motion of a right line about an immovable 
point arises the circle, etc. The constructions of figures, therefore, 
are motions ; now from constructions relations (affectiones) con- 
cerning the figures are demonstrated. Therefore from motion, and 
consequently a priori, and from cause. Geometry, therefore, is a true 
science. Therefore with Aristotle's consent its subject, namely space, 
will be a substance. Nor is it so very absurd that geometry treats 
of the substantial form of bodies. For behold the passage of Aristotle, 
13 "Met." chap. 3, in which he expressly says that geometry 
abstracts from matter, from the final and the efficient cause; in 
accordance with which supposition it follows that he treats either 
of the substantial or accidental form. But he does not treat of the 
accidental, because the accidental form in its own real definition 
involves the subject or matter in which it is, although Aristotle 
nevertheless says that geometry abstracts from matter. Therefore 
geometry treats of the substantial form. Hence there immediately 
arises in my mind as I write these things a certain beautiful harmony 
of the sciences, the matter, of course, having been accurately con- 
sidered : theology or metaphysics treats of the efficient cause of things, 
namely mind ; moral philosophy (whether practical or civil, for, as I 
learned from you, it is one and the same science) treats of the final 
cause of things, namely the good ; mathematics (I mean the pure, for 
the rest is a part of physics) treats of the form or idea of things, 
namely figure; physics treats of the matter of things, and of the 



APPENDIX 643 



single affection resulting from its combination with other causes, 
namely motion. For the mind in order to obtain for itself a good 
and pleasing figure and position of things, supplies motion to matter. 
For matter by itself is devoid of motion. For the origin of all 
motion is mind, as Aristotle also rightly saw. 

For to come to this point, Aristotle seems nowhere to have pictured 
to himself any such substantial forms, which are in themselves 
the cause of motion in bodies, as the Scholastics conceive; he 
indeed defines nature as the origin of motion and rest, and form 
and matter he calls nature, but form in a higher degree than matter, 
but from this what the Scholastics mean (volunt) does not follow, 
that form is a certain immaterial entity, irrational nevertheless in 
bodies, which itself spontaneously without the impact of an external 
thing gives motion downwards to a body, for example, to a stone. 
For the form, indeed, is a cause and soui'ce of motion, but not at 
first. For a body is not moved, except from the outside, as Aristotle 
rightly not only says, but also demonstrates ; for example, a globe 
may be in a plane, if it is once at rest it will not move of itself 
forever, unless in consequence of an added external impulsor, for 
example, another body. If this now approaches, the second body is 
the source of the impressed motion, but the figure, namely globosity, 
is the source of the motion taken up, for if globosity were absent, 
having been produced by chance according to circumstances, the 
body would not yield to the second body so easily. From this it 
is evident that the scholastic concept does not follow from the defi- 
nition of the Aristotelian form. Form, therefore, is the source of 
motion in its own body, and body itself is the source of motion in 
another body, I confess ; but the primary source of motion is the 
primary and in reality from matter abstracted form (which at the 
same time is efficient), namely mind. Hence liberty and spontaneity 
occur in minds alone. Therefore it is not absurd that of the substan- 
tial forms mind only is called the primary source of motion, the 
others having their motion from mind. And by this argument he 1 
ascends to the first mover. To this objection you give a twofold 
reply; first, this argument can avail nothing with Epicurus, who 
bestows upon his atoms per se downward motion. I admit that this 
argument can avail nothing with him, unless it be previously demon- 
strated to him that this itself is absurd and impossible, namely, that 
a body has motion from its own self, a thing which Cicero also if 
I am not mistaken already at that time did in his books "De natura 
Deorum," gracefully laughing at Epicurus because he introduced 
in this way something without cause and reason in his hypotheses. 
For in the nature of things nothing is down save as regards us, 

1 Aristotle. — Gerhardt's Note. — Tk. 



Gil LEIBNITZ'S CRITIQUE OF LOCKE 

and so there is no reason why any body should move in this 
rather than in that direction (plagcim). Therefore we shall easily 
answer Epicurus, denying that whatever is moved is moved by 
another outside itself, and shall vindicate the laboring certainty of 
the existence of God. Second, you object that Aristotle seems to 
have reasoned not so much from this axiom that the source of all 
motion is outside the moved body, as from the other that progress 
into infinity is not granted. But in truth, most noble sir, consider 
carefully whether or not either connection of ideas is needed. 
For unless it is admitted that what is moved extraneously is moved, 
plainly we shall arrive at no progress, still less at infinity ; for the 
opponent will resist steadfastly from the beginning and any given 
body will reply that it is itself sufficient to produce its own motion 
through its own substantial form, and needs therefore no mover, 
much less the first. Therefore that ladder will tumble down as 
soon as the first step, and as it were the foundation, is taken away. 
Then also Epicurus was wont to admit progress into infinity ; there- 
fore we must consider not so much what Epicurus admits or does 
not admit, as what can certainly be demonstrated. The Aristotelian 
philosophy, the inevitable result of the reformed philosophy itself, 
must be briefly touched upon. 1 It is plain that what must be dis- 
cussed by the theologians must be discussed by the philosophers 
also. The holy fathers illustrated the Holy Scripture by the best 
interpretations : soon the monks obscured them by superstitions. 
The light of souls having arisen, the reformed theology is three- 
fold: the one heretical, which rejects the scriptures themselves, as 
of the fanatics ; the second schism atical, which harmonizes the an- 
cient fathers, the doctors of the church, with the sacred scripture 
and the primitive church, as of the Evangelicals. 2 In like manner 
the Greek interpreters 3 illustrated Aristotle, the Scholastics obscured 



i-Tke Latin text reads: " Aristotelicam philosophiam reformats ipsius 
philosophise inevitabilis eventus breviter attingenda est." Gerhardt's note 
reads: " In diesem Satze fehlt etwas," i.e. In this sentence something is want- 
ing. Erdmann gives the following : "Observ. Thomasii. Sic scriptum erat a 
librario, sed hiat alias haec periodus: nee lectionem ejus constituo," i.e. Note 
of Thomasius. Thus it was written by the copyist, but this sentence is other- 
wise lacking : I do not determine its reading. — Tr. 

2 Gerhardt's note reads: "Auch hier scheint etwas zu fehlen," i.e. Here 
also something appears to be wanting. Erdmann gives the following : " Observ. 
Thomasii. Etiam hie aliquid deest ; datur enim pro triplici theologia tantum 
duplex. Scripsisse puto : alia schismatica, alia vera, qua? priscos Patres, etc. 
Confer sequentem," i.e. Note of Thomasius. Here also something is wanting ; 
for, instead of the threefold theology, only a twofold is given. I think he wrote : 
the second schismatic, the third true, which the ancient Fathers, etc. Cf. the 
following. — Tr. 

3 Gerhardt reads, " interpretes " ; Erdmann, " Patres." — Tr. 



APPENDIX 645 



him with trifles. The light having arisen, the reformed philosophy- 
is threefold : the first stupid, like that of Paracelsus, 1 Helmont, 2 and 
of the others who utterly reject Aristotle ; the second bold, which 
with small regard for the ancients, nay with open contempt for 
them, render(s) 3 (their) its own meditations even when good sus- 
pected, such as that of Descartes ; the third true, by whom Aristotle 
is recognized as a great man and in most things right. 

The reformed philosophy having just been reconciled with Aris- 
totle, it now remains to show its truth per se, precisely as the Chris- 
tian religion can be proved both from reason and history and from 
the sacred Scripture. But it must be proved that no entities are 
given in the world besides mind, space, matter, motion. Mind I call 
thinking being. Space is a primarily extended entity or mathemati- 
cal body, which manifestly contains nothing else than three dimen- 
sions, and is also that universal place of all things. Matter is a 
secondarily extended entity, or that which besides extension or math- 
ematical body has also physical body, that is, resistance, avriTv-n-tav, 
density, the power of filling (repletivitatem) space, impenetrability, 
which consists in this, that it is compelled by the approach of another 
such being to move or to stop the other; from which nature of im- 
penetrability therefore motion flows. Matter therefore is an entity 
which is in space or an entity coextensive with space. Motion is a 
change of space. But figure, magnitude, position, number, etc., are 
not entities really distinct from space, matter, and motion, but only 
conditions (habitudines) amid space, matter, motion, and their parts 
made by the supervenient mind. I define figure further as the ter- 
minus of extension, magnitude as the number of parts in the exten- 
sion. I define number as one, and one, and one, etc., or unities. 
Position is reduced to figure, for it is a formation (configuratid) of 
many (figures). Time is nothing else than magnitude of motion. 
And since every magnitude is a number of parts, what wonder 
Aristotle defined time as the number of motion ? But thus far ter- 
mini only have been explained, and the sense in which we use them 
set forth, but nothing as yet proved. Now let us show that there is 
no need of any other things in order to explain the phenomena of the 



1 Theophrastus Paracelsus, 1473-1541. On his philosophy, cf. Stockl, Gesch. 
d. Philos.d. Mlttelalters, III. [Vol.4], 430-452; Lasswitz, Gesch. d. Atomistik, 
1,298-306.— Tr. 

2 Joh. Bapt. Van Helmont, 1577-1644. On his philosophy, cf. Stockl, Gesch. 
d. Philos. d. Mlttelalters, III. [Vol. 4], 458-472 ; Lasswitz, Gesch. d. Atomistik, 
1, 343-351. — Tr. 

3 The Latin text reads, " suas suspectas reddunt," as though the writer had 
in mind those holding the view rather than the view itself with which the 
sentence began, and in consistency with which beginning the verb should 
have been " reddit." — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



world and to assign their causes, nay, also that there can be no other 
things, although if we show that there is no need of other things 
besides mind, matter, space, and motion, by this very thing it will 
be shown that the hypotheses of the moderns who employ these 
things alone in the assignment of phenomena are the better. For it 
is a defect in an hypothesis to assume unnecessary things. Now that 
all things in the entire world can indeed be explained from these 
alone, the reading of the modern philosophers sufficiently teaches, and 
it is evident from the considerations which I put down a little before 
when I was showing the possibility of an Aristotelic harmony. Then 
it must also be noted that these hypotheses are the better which are 
the clearer. Now, indeed, the human mind can imagine nothing else 
than mind (when, namely, it thinks of itself), space, matter, motion, 
and what results from these when united with each other ; whatever 
else you add are words only, which can be named and variously 
combined with each other, but cannot be explained and understood. 
For who can imagine to himself a being which partakes of neither ex- 
tension nor thought? What need therefore to posit souls of animals 
and plants, the incorporeal forms of the elements, the substantial 
forms of the metals, devoid of extension ? More correctly there- 
fore Campanella 1 in his book "De Sensu rerum et Magia," and Marcus 
Marci, 2 " De Ideis operatricibus," falsely indeed, yet in agreement 
nevertheless with their hypotheses, attributed to these substantial 
forms of inanimate things, deprived of extension, sense, knowledge, 
imagination, will. Nor is the occult philosophy of Agrippa, 3 who adds 
an Angel as it were an obstetrician to everything, unlike it, nor the 
discussions of Scaliger 7repi Swafxews 7rAao-Tt/<^s and its intelligence. 
Thus it returns to as many little gods (deunculos) as substantial 
forms, and to a race almost 7roXvdcicr/ji6v. For hence is attributed to 
them appetite, and the natural instinct from which also follows 
natural cognition, hence these axioms : Nature does nothing in vain, 
everything shuns its own destruction, like takes pleasure in like, 
matter desires a nobler form, and others of this description, since 
nevertheless there is, in truth, in nature no wisdom, no appetite, but 
a beautiful Order springs out of it, because it is the clock of God. 
From these considerations it is evident that the hypotheses of the 
reformed philosophy are superior to the scholastic hypotheses for this 

1 Tommaso Campanella, 1568-1639. Brief account of his views is given 
in Lasswitz, Gesch. d. Atomistik, 1, 340-343. , Cf., also, Stockl, Gesch. d. 
Philos. d. Mittelalters, III. [Vol. 4], 343-366.— Tr. 

2 Cf. infra, p. 676, n. 2. — Tr. 

3 Heinrich Cornelius Agrippa von Nettesheim, 1486-1535. His Opera omnia, 
Lugcluni, 1600; the De occulta philosophia in Vol. 1. For an account of his 
views, cf. Stockl, Gesch. d. Philos. d. Mittelalters, III. [Vol. 4], 412-426; 
Lasswitz, Gesch. d. Atomistik, 1, 290-293. — Tr. 



APPENDIX 647 



reason, because they are not superfluous, while, on the other hand, they 
are clear. 

It remains for us to prove by more subtle reasoning that other 
entities than those I have mentioned cannot indeed be assumed 
in explaining the nature of bodies. It will be done thus: All call 
that body which is endowed with some sensible quality, then out 
of the sensible qualities many can be taken away, provided never- 
theless that the body remains. For although a body is deprived of 
all color, odor, taste, yet it is called a body. For you will grant 
that air, for example, is a body, although it is transparent, and 
so not colored, besides it is devoid of taste, and for the most part also 
of both odor and sound. Therefore the qualities visible, audible, and 
those of taste and smell, may be cast aside as least constitutive 
of the nature of body. To tactile qualities, therefore, everything 
returns. And indeed these primary qualities — heat, moisture, dry- 
ness, cold — can each be absent ; heat can be absent from water, 
moisture from the earth, dryness from the air, cold from the fire, and 
yet any of these is a body. The other tactile qualities — for example, 
smoothness, lightness, tenacity, etc., are acknowledged even by you 
not to belong to the constitutive nature of a body, for this very 
reason, because they are called secondary, and so have arisen from 
others, and further because there is no one of them which cannot be 
absent from a body. There remains, therefore, to be sought for some 
sensible quality which is competent to all and single bodies and from 
which as it were by a sign men may distinguish body from non-body. 
This without doubt is density (crassities), or avriTv-n-ia, taken with 
extension. Whatever men certainly think extension is (although 
in truth it always is body and has dvTmm'a, although insensible 
to us, yet perceptible by the intellect), they do not at once call that 
body, for they sometimes think that it is a mere appearance and 
(j>dvTacr/xa. But whatever they not only see but also touch, that is, in 
which they find avTirvTrca, that they call body ; but whatever lacks 
avTtTVTria, that they deny to be body. In the two, therefore, men 
both educated and uneducated place the nature of body, in extension 
and avTirvTTia taken together ; they take that from sight, this from 
touch ; whence also from the union of both senses we are wont to be 
certified concerning things that they are not phantasmata. But 
extension is nothing else than existence in space; avriTviria is the 
inability to exist with another in the same space, but the one or the 
other (alterutrum) must be moved or keep quiet. From these con- 
siderations it is evident that the nature of body is constituted by 
extension and antitypy, and since there is nothing in things without 
cause, nothing even must be assumed in bodies, the cause of which 
cannot be made to appear from their primary constitutive principles. 
Now the cause cannot be made to appear from these except through 



648 LEIBNITZ'S CRITIQUE OF LOCKE 

their definitions. Nothing, therefore, is to be assumed in bodies 
which does not flow from the definition of extension and antitypy. 
But there flow from this definition only magnitude, figure, position, 
number, mobility, etc. Motion itself does not flow from these. Whence, 
properly speaking, motion is not given in bodies as a real entity 
in them, but I have demonstrated that whatever moves is continually 
created, that bodies at any instant in assignable motion are some- 
thing, at any intervening time between the instants in assignable 
motion are nothing, a thing which was unheard of till now, but 
which is plainly necessary and will shut the mouth of the atheists. 
From these considerations it is evident that the explanation of all 
qualities and changes must be taken from magnitude, figure, motion, 
etc., and that heat, color, etc., are nothing but subtile motions and 
figures. As to what remains, I dare affirm that atheists, socinians, 
naturalists, sceptics, would never have been truly met unless by this 
established philosophy ; which I indeed believe a gift of God given 
to the old age of the world as an unique plank by which pious and 
prudent men are about to save themselves in the shipwreck of the 
now overhanging atheism. However small my knowledge of learned 
men after a little time, I nevertheless tremble as often as I think how 
many men at the same time intellectual and absolutely atheistic 
I have met. And there is flying through the hands of men an 
unknown book of Bodin 1 (and would, as I wish in the case of 
Naudseus, it was never to be published), powerful certainly, which he 
calls, " Arcana sublimium," in which he is the professed enemy 
of the Christian religion. The dialogues of Vaninus 2 are child's play 
when compared with it. I have read it carefully, and I thank God 
from my heart, because he furnished me with those defences of 

1 Jean Bodin, 1530-1596 or 1597, the eminent writer on Political Science, 
and advocate of tolerance in religion, published his greatest work, — "the first 
elaborate attempt in modern times to construct a system of political science," 
— Les six Livres de la Republique, at Paris, 1576. His Universse naturse 
theatrum appeared at Hanover, 1605, the Preface dated February 25, 1596. 
For some account of its doctrine, cf. Lasswitz, Gesch. cl. Atomistik, 1, 326- 
327, 411^13. G. E. Guhrauer published an Abstract, in German, with a 
partial translation of the Latin text, of his very famous MS., here referred to 
by Leibnitz, the Colloquium heptaplomeres de abditis rejourn sublimium arca- 
nis, Berlin, 1841, and the complete original text, from a MS. in the Giessen 
Library, was edited and published by L. Noack, Schwerin, 1857. The work is 
"a conversation between seven learned men, — a Jew, a Mahometan, a 
Lutheran, a Zwinglian, a Roman Catholic, an Epicurean, and a Theist " ; 
and "the conclusion to which they are represented as coming is, that they 
will live together in charity and toleration and cease from further disputa- 
tions as to religion." — Tr. 

2 Lucilio Vanini, 1585-1619, who called himself by the name, among others, 
of Julius Csesar, was a disciple of Pomponatius (cf. ante, p. 581, n. 1). He 
denied the immortality of the soul, and advocated a doctrine of pantheistic 



APPENDIX 649 



philosophy (in which I should be ungrateful, if I should deny that 
I owed much to you), by which I repelled his weapons with no 
difficulty. The labor of the distinguished Spizel is to be praised, 
which he now again expends in eradicating atheism. His letter 
on this subject, recently published (in these nine days), I think you 
have seen. Hear what happened to me in connection with him. 
I had written some time when at leisure, a leisure nevertheless 
disturbed in the inn, about two sheets, in which I was discussing 
the demonstration more accurately than usual of the immortality 
of the soul and the existence of God. These I had sent to my 
friend. Through him they came into the hands of the Most Rev- 
erend Spener, 1 pastor at Frankfort, a neglected yet deserving author. 
Spener sent them to Spizel ; 2 Spizel placed them at the end of 
that recent letter of his to Ant. Reiser 3 on the eradication of 
atheism, under the title " Confessio naturae contra atheistas." I 
do not blame him, but I am grieved, because that cr^e'Stov was 
so very incorrectly printed ; that sorites, especially, by which I tried 
to demonstrate the immortality of the soul, was thrown into strange 
confusion by the misplacing of its opening lines. Spizel acknowl- 
that he was ignorant of the author. I desire a judgment' 



naturalism. He published Be admirandis naturse regime, deseque mortalium 
arcanis, lib. quat., Paris, 1616. His philosophical works, translated into 
French by Rousselot, appeared at Paris, 1841. Leibnitz, in a letter to Sebas- 
tian Kortholt, March 15, 1713, says: " Apologiam Vannini nondurn vidi, nee 
magnopere dignarn legi puto. Scripta ejus parvi momenti sunt, sed homo 
ineptus, imo stultus comburi non rnerebatur, claudi jure poterat, ne alios 
inficeret" (Dutens, 5, 321).— Tr. 

1 Philip Jacob Spener, 1635-1705, was chief pastor of the Lutheran church 
at Frankfort-on-the-Main, from 1666-1686, first Court-chaplain at Dresden, 
1686-1691, and rector of St. Nicolas, in Berlin, with the title of " Consistorial- 
rath," from 1691. He directed the foundation of the University of Halle in 
1691. Though, according to Ritschl, Gesch. d. Pietismus, 2, 163, Bonn, 1884, 
" himself not a Pietist," Spener has justly been called "the father of Pietism." 
He was a voluminous author. Two letters of Leibnitz to Spener are given by 
Dutens, 5, 467-468. — Tr. 

2 Theophil Gottlieb Spitzel, or Spizel, 1639-1691, a German pastor and poly- 
historian, was deacon of St. James's church, Augsburg, in 1662 and pastor from 
1682 to 1690. "Asa theologian, in spite of his many-sided and universal sci- 
entific interests, he remained well-nigh unfruitful." Leibnitz refers to the 
matter here alluded to again in his letter to Spizel, December 12-22, 1669; cf. 
Dutens, 5, 343. The Confessio Naturae contra Atheistas first appeared as a 
Postscriptum in Theo. Spizelii de Atheismo eradicando ad Virum prsestantis- 
simum Br. Antonium Reiserum Augustanum, etc., Epistola. . . . August. 
Vindel. 1669.— Tr. 

3 Anton Reiser, 1628-1686, a learned and distinguished Lutheran theologian, 
was an earnest defender of evangelical truth. He published Be origine, pro- 
gressu et incremento antitheismi seu Atheismi, Augsburg, 1669, 8vo ; Index 
MSS. bibliothecse Augustanse, Augsburg, 1675, 4to. — Tr. 



650 LEIBNITZ'S CRITIQUE OE LOCKE 

concerning the reasoning itself of the demonstration. Nor do I 
seek praise, but criticism, since it is important to religion that it 
be not perfunctorily defended. Although meanwhile I seem to 
myself to have penetrated far more deeply into both. For neither 
the thoughts which I have thrown out since that time concerning 
perpetual creation in motion, nor the inmost nature of thinking 
being or mind, are brought together therein. 1 wrote you at one 
time about the society which certain Germans are starting. It 
will show its existence by a German paper published by the book- 
seller Goezius with the title "Collegium Philadelphicum." But to 
me it seems a pleasant dream, like the society of the Red Cross. 
It is wonderful how great a dissension in Parnassus that Schurz- 
fleisch x who is with you excited. I very much wish to know what 
the great men with you by whom he hopes he will be advanced, 
think of this specimen. Boeder 2 threatens that one from the court. 
The author of the " Itinerarium politicum " which is now appearing 
is without doubt Burgoldensis, 3 that commentator on the " Instru- 
mentum pacis." I am astounded at the audacity of the man. 

As for the rest, most illustrious sir, I have discoursed the more 

1 Konrad Samuel Schurtzfleisch, 1641-1708, was Professor of History at 
Wittenberg, and because of his great learning was given the nickname of a 
living library and a walking museum. While at Wittenberg he published, 
under the name of Eubulus Theosdatus Sarckmasius, a pamphlet, Judicia de 
novissimis prudentise civilis Sei'iptoribus, Leipzig, 1669, in which he freely ex- 
pressed his opinion of the most celebrated German jurisconsults, and which 
aroused against him many adversaries. He continued the history of Sleidan 
(c/. ante, p. 114, n. 1). — Tr. 

2 Johann Heinrich Boeder, 1611-1692, Professor of Eloquence at Strassburg 
and Upsala, and afterwards of History at Strassburg, was author of many 
commentaries on classical authors and of works of history, politics, criticism, 
morals, etc. Among them were : Be jure Gallise hi Lotharingiam, Strass- 
burg, 1663; Ad Grotium de jure belli et pacis dissert., V., 1665. The Elector 
of Mayence appointed him " conseiller " in 1662, and the next year the Em- 
peror Ferdinand III. bestowed on him the same title and made him Count 
Palatine. — Tr. 

3 Philippus Andrea Oldenburgerus, the anagram of which is Burgoldensis, 
a pupil of H. Conring, was Professor of Law and History at Geneva, where he 
died in 1678. He published a large number of valuable works, some of them 
under assumed names, among which are : Itinerarium Germanise. Politicum, 
modernam pmcipuarum Aularum Imperii faciem repriesentans, Cosmopoli 
(Geneva) , 1668, 12mo ; Limnseus enucleatus, an abstract of Limne, De jure 
imperii Romano-germanici, Geneva, 1670, fol. ; Notitia Imperii, sive Biscur- 
sns in Instrumentum, Pacis Osnabrugo-Monasteriensis (this work under the 
name of Burgoldensis), Freistadt, 1669, 4to. Of the Itinerarium Germanise 
Politicum, Morhof, Polyhistoria, 2, 497, says: "in quo multa est rerum inep- 
tissimarum farrago, quibus nonnunquam immiscentur aliqua notatu non in- 
digna, sed lectore prudente opus est, qui cum judicio ilia legere posit." The 
freedom with which the author spoke of the political interests and vices of the 
German courts led to the interdiction of his book. It was, nevertheless, 



APPENDIX 



at length of this whole matter to you for this reason, because I 
had no more learned and equitable judge of these things. Since 
you have examined all the recesses of the ancients and do not 
despise the discoveries of the moderns when deserving, you alone 
of all can best examine this and also illustrate them. For you 
rightly judge, that although new opinions are brought forth and 
their truth most evidently shown, yet from the views publicly 
received we must scarcely ever depart, a thing which we should not 
strive for if the Scholastics had done it. Farewell, ornament of 
our country, and do not bring to an end (absolve) your noble thoughts 
(for many are both begun and at the same time perfected with rare 
felicity of mind), but produce them. 



II 
FRAGMENT 1 

[From the Latin] 

The primary matter 2 of Aristotle is identical with the subtile matter 
of Descartes. Each is divisible to infinity. Each is per se lacking in 
form and motion, and each receives forms through motion. Each 
receives motion from mind. Each is formed into certain rings (gyros), 
and there is no more solidity in the vortices of Aristotle than of 
Descartes. Each has solidity from motion, because nothing drives 
it asunder, although Descartes himself has not assigned this cause 
of solidity. Each ring (gyrus) extends (propagat) the action im- 
pressed through motion on account of the continuity of matter into 
another ring. For Aristotle also, no less than Descartes or Hobbes, 
derives all particulars from the motion alone of universal rings. 
Whence Aristotle adds intelligences only to the principal rings, 
because from the impacts of these rings the actions of the others 
follow. In this Aristotle erred, because he made the earth the 
centre of the universe and of all gyrations. But he should be par- 
several times reprinted. In Pt. IV. of his Thesaurus rerum publicarum totius 
orbis, Geneva, 1675, 4 vols., 8vo, he repudiated the errors and condemned the 
reprehensible expressions which he had employed in the earlier work. Of the 
Discursus in Instrument um Pads, Lenglet du Fresnoy remarks : " a bold and 
learned piece." — Tr. 

1 Gerhardt, Leibniz. philos. Schrift., 7, 259-60. In his Einleitung, ibid., 251, 
G. says : " The fragment, n. I., which was written, perhaps, at the time of tbe 
composition of the Hypothesis pjhysica (1671), contains a comparison of the 
metaphysics of Aristotle and Descartes, what Leibnitz borrowed from both, 
and what he has added of his own." — Tr. 

2 Upon a bit of paper without date and superscription, proceeding according 
to the handwriting from the earliest period. — Gerhardt' s Note. — Tr. 



LEIBNITZ'S CRITIQUE OE LOCKE 



cloned for this, because philosophy was not yet sufficiently instructed 
by observations. 

To these I now add, that primary matter if at rest is nothing. This 
also is a statement which certain Scholastics have obscurely made, 
that primary matter also has existence from form. Of this fact 
there is demonstration. Because whatever does not think, is nothing. 
But that in which there is no variety also does not think. In 
like manner : If primary matter moves in one direction, that is, 
in parallel lines, it is at rest, and consequently is nothing. All 
things are full, because primary matter and space is the same thing. 
Therefore every motion is circular, either composed of circulars or 
at least returning into itself. Many circulations mutually hinder 
each other, or mutually lead into each other. Many circulations try 
to unite in one or all bodies tend to rest, that is, annihilation. If 
bodies are without mind, it is impossible for motion to have been eternal. 1 
From universal conflicting circulations are produced particular bodies. 
Matter is actually divided into infinite parts. There are infinite creatures 
in any given body whatever. All bodies cohere among themselves. All are 
indeed forcibly separated (distrahuntur) from all, but not without resist- 
ance. There are no atoms, or bodies whose parts are never forcibly 
separated. There are two principles by which motion is changed : 
compositions of efforts (conatuum), and compositions ... [a word 
and two lines are in consequence of the destruction of the paper 
illegible. — Gerhardt]. 



Ill 

DEMONSTRATION AGAINST ATOMS TAKEN FROM 
THE CONTACT OF ATOMS 2 

October 23, 1690 

[From the Latin] 

Definition I. A thing is distinguished from other things in two 
ways, either through itself, or extrinsically. Through itself a thing is 
distinguished from another, when a method of distinguishing through 
the consideration alone of the thing is used, no operation or change 
being made in the thing. Extrinsically, when by external application 
something new is produced in the thing, which does not appear in 

1 Over the words, " mo turn fuisse aeternum," Leibnitz has written, " potest 
diminui sine fine," i.e. can be diminished without end. — Gerhardt's Note. — Tr. 

2 Gerhardt, Leibniz, philos. Schrift., 7, 284-288; Stein, Leibniz, u. Spinoza, 
Beilage XIV., pp. 325-328. — Tr. 



APPENDIX 653 



another. Thus the sphere and the cube can be distinguished both 
by consideration and also by operation ; by consideration, because in 
the sphere no angles are found, of which there are eight in the cube ; 
by operation, as, if both are placed upon an inclined plane, the sphere 
will descend the plane by rolling, the cube by sliding. 

Axiom. Whatever is distinguishable extrinsically from another, is 
also distinguishable through itself. 1 

For example, let there be two coins from the same stamp (typo), one 
of true gold, the other of false, which may be easily distinguished 
extrinsically by the blow of the hammer. I say even before the 
blow, by an attentive consideration, differences in the composition 
itself of each would be detected by the naked or equipped eye, and 
although the keenness of vision could not reach thither, yet differ- 
ences exist within and can be detected by some more acute creature 
(for example, by an angel). 2 

Observation. Certain bodies are mutually separated violently 
from each other. 

Conceded Hypothesis. Matter is uniform, or, motion and figure 
excepted, everywhere like itself. 

Definition II. An Atom is a body which cannot be broken. 

Postulate. If there are atoms, we may assume them of any figure 
and size whatever and in any position whatever. 

theorem. 

It is impossible for all bodies to consist of atoms. 

Let us assume (by the postul.) three atoms, A, B, C, of which A is 
cubical, but B and C are triangular prisms, composing the cube D, 
similar and equal to the former A. The cube D cannot (by the 
conceded hypothesis) be distinguished from the cube A. Therefore 
they cannot be distinguished extrinsically (by Axiom I.). If there- 
fore other bodies strike against the cube D, they will be able either 
to separate the atoms B and C, or they will not be able. If able to 
separate them, then the same bodies striking in the same way against 

1 On the margin of the Ms., Leibnitz has remarked : " Whatever is dis- 
tinguishable in itself, is also distinguishable extrinsically. If two bodies are 
similar through a third similar body, they cannot be distinguished. If two 
bodies are similar, but mutually unequal per se, they can be distinguished, 
no third body even being assumed. Similar and equal bodies cannot be dis- 
tinguished extrinsically, nay, rather, in any way, and so are one and the same." 
— Gerhardt's Note. — Tr. 

2 Stein here inserts in his text the following marginal gloss, wanting in 
Gerhardt's text : "Hie ostenditur ex hypothesi Atomistica sequi, quod novae 
Atomi nasci possint, nee tamen iterum dissolvi contra naturae morem," i.e. 
Here it is shown to follow from the Atomistic hypothesis, that new atoms can 
be produced, but nevertheless cannot again be dissolved contrary to the law 
of nature. — Tr. 



654 



LEIBNITZ'S CRITIQUE OF LOCKE 



the cube A will be able violently to separate the same into parts, for 
otherwise A and B might be distinguished extrinsically (by Defin. I.), 
the contrary of which has been shown. But if the cube A is vio- 
lently separated into parts, it certainly (by Defin. II.) will not be an 
atom, as was supposed. But if other bodies cannot again separate 
the cube D into component parts, it follows that the atom was not 




produced from non-atoms through contact. And the same principle 
will hold, whatever figure the atoms be assigned. Whence it follows 
that atoms which have once touched each other cannot again be 
violently separated. Now if all bodies are composed of atoms, bodies 
do not touch each other except through the atoms. Therefore they 
cannot be violently separated after contact, unless the atom of the 
one is violently separated from the atom of the other, which we 
have shown cannot be done. But bodies not be violently sepa- 
rated. . . . x And so it is not true that all bodies are composed of 
atoms, q. e. d. 

Scholium to the Demonstration against Atoms taken 
from the Contact op Atoms. 



I do not see what reply can be made to this demonstration unless 
by a denial of the postulate. For we postulated that it be conceded 
us : If there are atoms, they can be assumed of any figure and size 
and in any position whatever. This alone seems possible to be said with 
any reason, atoms cannot be granted, the parts of which are connected 
only by a point or line. And so there cannot (for example) be an 

1 More words illegible. — Gerhardt's Note. Stein omits this incomplete 
sentence. — Tr. 



APPENDIX 655 

atom similar to one composed from two spheres touching each other. 
But if then atoms spherical or terminated by any other curved sur- 
faces whatever are granted, they never touch each other save in a 
point, and so never compose a body similar to an atom. Here in 
some way I think a reply can be made, in the first place if the contact 
in the surface is. the cause of stability, it follows that stability is 
greater when the surface is greater. Whence the atoms would not 
be equally stable. And so there would be a certain determinate 
force of violent separation by which stabilities could be measured. 
I do not see where we can find this force, if it is not in the motion of 
bodies, unless we advocate certain spiritual powers whose method of 
acting in bodies nevertheless cannot be known. But if the stability 
of all atoms is equal, it does not matter how great the contact is ; 
even contact in a line, nay in a point, would suffice. 

A second reply which can be made is this : it has at least been 
demonstrated by us that bodies cannot be composed of atoms ter- 
minated by plane sides. But besides the fact which can be doubted, 
whether indeed curvilinears properly called are granted, this excep- 
tion does not seem in agreement with the reasons of things, that if 
composition from atoms is possible it must necessarily take place 
through bodies destitute of a plane surface. 

The third reply is this : not only the atoms of plane surfaces but 
also of concave must be assumed (tollendas) from nature. Otherwise 
we shall be permitted to make atoms from the non-atom, as often as 
the concave surface of one atom happens to be applied to the convex 
surface of another, and that will happen until all the atoms of the 
concave surfaces shall be filled as far as can be done by the convex 
existing in nature. But this restriction also does not seem in har- 
mony with the reasons of things. And in general, if any one denies 
that there are other atoms than the perfectly spherical, in order to 
escape the force of the demonstration, these things are devised which 
indeed are accommodated to the latter, but do not accord with the 
primal reasons and amplitude of nature. In brief : from the hypo- 
thesis of atoms I can deduce absurdity, provided I am allowed to 
assign to the atoms size, figure, and motion as I will. 1 

1 On the margin of the Ms., Leibnitz has remarked : " Another argument 
could he set up, namely: If atoms could be granted, bodies similar and equal, 
aud nevertheless different from each other, as would be two equal spheres, 
could be granted. If atoms were granted, no cause of reflection, which in fact 
must be taken from an elastic body {Elaterio), could be perceived, nor would 
the atoms striking each other leap apart, in turn, from each other. Further 
superficial contact is the cause of cohesion, two atoms coming together in 
sides or surfaces would not leap apart ; thus, if the velocity of each approach 
is equal, the whole force would perish." — Gerhard? s Note. Stein has put this 
marginal gloss into the text, with a note stating that it is a marginal gloss. 
— Tr. 




656 LEIBNITZ'S CRITIQUE OF LOCKE 



Appendix to the Demonstration against Atoms taken 
from the Contact op Atoms. 

If any -one denies that there can be atoms, the parts of which touch 
each other in a point only or line, and so requires contact in the sur- 
face for cohesion, that he may avoid the force of our demonstration, 
that one will entangle himself in other new difficulties. 

For if cohesion arises from superficial contact, a case can be seen 
in which an atom is unable to graze (radere) an atom ; for where a 
part of the side of the atom B coincides with a 
iA part of the side of the atom S A, they are not 
only unable to leap apart and also to separate 
violently, but even the one will not be able to 
slide upon the other, for they touch each other 
in the surface. ^Nay, rather, what is more 
wonderful, the atom A coming by its own mo- 
tion from the place Y A into the place 2 A so 
situated, that it is unable to proceed farther, because it grazes the 
atom B, is there arrested without any obstacle as if it were an en- 
chanted object. Nor does it suffice to say that no such atoms are 
given, and that no others exist unless spherical or at least bounded 
by convex surfaces. For it suffices that atoms bounded by plain or 
concave sides are possible, if those bounded by convex sides are 
possible ; and from the supposed possibility of these that which is 
absurd follows, whence it follows that convex atoms are not to be 
admitted. 

Bat if any one because of these considerations now requires no 
longer superficial contact only, but also the rest of bodies tangent to 
each other for cohesion, lest forsooth one atom be kept from sliding 
upon another, that one is unable to bring forth proof of his opinion, 
nor does it appear why the nature and the force of the present state 
which is contact must depend upon a past state, so that forsooth the 
present contact causes cohesion, if it has remained for some consider- 
able time in the same place, as if there were need of a certain habi- 
tude, whence indeed it would follow that stability is increased by 
duration and that atoms newly produced are the more stable the 
longer they cohere, a fact which no one will surely easily affirm. But 
neither can the moment be assigned in which the cohesion of two 
atoms begins, because it is entirely perfect at once. And if it does 
not begin unless it has continued for some time, it will never begin, 
for it would itself be prior to itself. Moreover, all rest can be under- 
stood as composed of two motions, so that if a body is moved at the 
same time by two moving bodies and so remains quiet accidentally, 
shall it then be understood also to adhere to the sides of another body 



APPENDIX 657 



which it grazes ? And so whithersoever we are turned, we fall into 
a-n-opa, which is not strange, because we assumed an hypothesis lack- 
ing in reason, namely, that the highest stability is without an intelli- 
gible cause. 

But if any one thinks that atoms can be produced at least by the 
decree of God, we confess to him that God can make atoms, but a 
perpetual miracle would be needed to resist a forcible separation, 
since in a body itself a principle of perfect stability cannot be per- 
ceived. God can perform whatever is possible, but it is not always 
possible to transfer his power to creatures, and to bring it to pass 
that they themselves can do per se what they accomplish through his 
own power alone. 



IV 

ESSAY ON DYNAMICS ON THE LAWS OF MOTION, IN 
WHICH IT IS SHOWN THAT NOT THE SAME QUAN- 
TITY OF MOTION IS PRESERVED, BUT THE SAME 
ABSOLUTE FORCE, OR RATHER THE SAME QUANTITY 
OF MOVING ACTION (L' ACTION MOTRlCEy 

[From the French] 

The opinion that the same quantity of motion is preserved and 
abides in the concourse of bodies has reigned a long time, and passed 
as an incontestable axiom among modern philosophers. We under- 
stand by the quantity of motion the product of the mass by the velocity, 
so that the mass of the body being as 2 and the velocity as 3, the 
quantity of motion of the body will be as 6. Thus if there were two 
concurrent bodies, multiplying the mass of each by its velocity and 
taking the sum of the products, it is maintained that this sum must 
be the same before and after the concourse. 

We begin now to be disabused of this opinion, especially since it 
has been abandoned by some of its most ancient, most skilful, and 
most eminent defenders, and above all by the author himself of the 
" Search after Truth." " 2 But in this case an inconvenience has arisen, 
namely, that we have been thrown too far into the other extreme, and 
do not recognize the conservation of anything absolute which might 
hold the place of the quantity of motion. But our mind looks for 
this, and it is for this reason that I remark that philosophers who do 

1 Gerhardt, Leibniz, math. Schrift., II. 2 [Vol. 6], pp. 215-231. Published 
from the Ms. in the Royal Library at Hanover. Written, according to Ger- 
hardt, probably about 1691, cf. op. cit., Einleitung, p. 11. — Tr. 

2 Cf. ante, p. 176, note 1. — Tr. 

2 o 



658 LEIBNITZ'S CEITIQUE OF LOCKE 

not enter into the profound discussions of mathematicians have diffi- 
culty in abandoning an axiom such as this of the quantity of con- 
served motion without giving themselves another to which they may 
hold. 

It is true that the mathematicians who a long time since established 
the rules of motion based on experiments have remarked that the 
same relative velocity is preserved between the concurrent bodies. 
For example, if one of the two is at rest, or if both are in motion, and 
proceed the one against the other, or in the same direction, there is a 
relative velocity, with which they approach or depart the one from the 
other ; and we find that this relative velocity remains the same, so 
that the bodies depart after the impact with the velocity with which 
they were approaching before the impact. But this relative velocity can 
remain the same although the true velocities and absolute forces of 
the bodies change in an infinite number of ways, so that this conser- 
vation does not concern that which is absolute in bodies. 

I remark also another conservation, namely, that of the quantity of 
progress, but neither is this the conservation of that which is abso- 
lute. I call progress the quantity of motion with w T hich a body pro- 
ceeds in a certain direction, so that if the body went in a contrary 
direction, this progress would be a negative quantity. Now if two or 
more bodies are concurrent, we take the progress from the direction 
whence proceeds their common centre of gravity, and if all these 
bodies proceed from the same direction, then we must take the sum 
of the progress of each for the total progress; and it is plain that in 
this case the total progress and the total quantity of motion of the 
bodies are the same thing. But if one of the bodies proceeded from a 
contrary direction, its progress in the direction in question would be 
negative and consequently must be subtracted from the others in 
order to have the total progress. Thus if there are only two bodies, 
one of which proceeds in the direction of the common centre, and the 
other in a contrary direction, from the quantity of motion of the first 
must be subtracted that of the second, and the remainder will be the 
total progress. Now it will be found that the total progress is con- 
served, or that there is as much progress in the same direction before 
or after the impact. But it is also plain that this conservation does 
not correspond to that which is demanded of something absolute. 
For it may happen that the velocity, quantity of motion, and force of 
bodies being very considerable, their progress is null. This occurs 
when the two opposed bodies have their quantities of motion equal. 
In such case, according to the sense we have just given, there is no 
total progress at all. 

Long since I corrected and rectified this doctrine of the conser- 
vation of the Quantity of Motion, and put in its place the con- 
servation of some other absolute thing; but as regards the precise 



APPENDIX 659 



form in which this doctrine should be conceived, 1 that is to say, the 
conservation of absolute force, it is true that commonly they do not 
appear to have entered sufficiently into my reasons nor to have appre- 
hended the beauty of that which I have observed, as I remark in all 
that has been published in France or elsewhere on the laws of motion 
and mechanics, even after what I have written on Dynamics. But as 
some of the most profound mathematicians after many discussions 
have yielded to my opinion, I promise myself with time general ap- 
proval. To return then to what I said of the conservation of absolute 
force, we must know that the origin of the error concerning the quan- 
tity of motion arises from that which has taken it as force. We have 
been led, I think, naturally to believe that the same quantity of the 
total force abides before or after the impact of the bodies, and I have 
found this very true. Now the quantity of motion and force being 
taken as one and the same thing, we have concluded that the quan- 
tity of motion is conserved. What has contributed the most to con- 
found force with quantity of motion is the abuse of the static doc- 
trine. For we find in statics that two bodies are in equilibrium when 
in virtue of their position their velocities are reciprocal to their 
masses or weights, or when they have the same quantity of motion. 

But we must know that this equality of force in this case arises 
from another principle, for generally absolute force must be estimated 
by the violent effect which it can produce. I call the effect violent 
which consumes the force of the agent, as, for example, to give such 
a velocity to a given body, to raise a given body to such a height, etc. 
And we can conveniently estimate the force of a heavy body by the 
product of the mass or of the weight multiplied by the height to 
which the body might rise by virtue of its motion. Now two bodies 
being in equilibrium, their heights to which they might rise or from 
which they might descend are reciprocal to their weights, or rather 
the products of the heights by the weights are equal. And it happens 
only in the case of equilibrium or of dead force, that the heights are 
as the velocities, and that thus the products of the weights by the 
velocities are as the products of the weights by the heights. 2 This, 
I say, happens only in the case of dead force, or of the infinitely small 
motion which I am accustomed to call solicitation, which takes place 

1 The French is: " Mais justement de cette chose qu'il fallait." — Tr. 

2 On the margin of the manuscript Leibnitz has remarked : " Thus it is 
astonishing that Descartes has avoided so well the rock of velocity taken for 
force, in his little treatise on Statics or dead force, where there was some 
danger, having reduced all to weights and heights, when it was indifferent, 
and that he has abandoned the heights for the velocities in the case where 
he should have done wholly the contrary ; that is to say, when he discusses 
percussions or living forces which must he measured by weights and heights." 
— Gerhardt's Note. — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



when a heavy body tries to commence movement, and has not yet 
conceived any impetuosity ; and this happens precisely when bodies 
are in equilibrium, and, trying to descend, are mutually hindered. 
But when a heavy body has made some progress in descending freely, 
and has conceived some impetuosity or living force, then the heights 
to which this body might attain are not proportional to the veloci- 
ties, but to the squares of the velocities. And it is for this reason 
that in case of living force the forces are not as the quantities of 
motion or as the products of the masses by the velocities. 

Nevertheless it is noticeable, and has contributed to the error, 1 that 
two bodies unequal in absolute living force, — for it is of this I speak, 
— but whose quantity of motion is equal, can stop each other, which 
fact has made men believe them absolutely equal in force ; as, for 
example two bodies A of mass 3 velocity 2, and B of mass 2 velocity 3. 
For although A is absolutely weaker than B, A being able to raise 
a pound only 12 feet, if B can raise a pound 18 feet ; nevertheless in 
the concourse they can stop each other, the reason of which is that 
bodies are hindered only according to the laws of dead or static force. 
For being elastic as we suppose, they act between themselves only by 
dead forces or according to the equilibrium in the concourse, that is 
to say, by inassignable changes, because in pressing, resisting, and 
continually weakening each other more and more until they come to 
rest, they destroy one another at each moment only by the infinitely 
small motion, or dead force, equal on both sides ; now the quantity of 
dead force is estimated according to the laws of equilibrium by the 
quantity of motion, infinitely small in truth, but whose continual 
repetition exhausts at last the whole quantity of motion of the two 
bodies, which being supposed equal in both bodies, each quantity of 
motion is exhausted in the same time, and consequently the two 
bodies are reduced to rest in the same time by the pressures of their 
elasticities, which, restoring themselves afterwards, reproduce the 
motion. It is (in) this continual diminution of the quantity of motion 
according to the equilibrium in the concourse of the two elasticities 
that the cause of this paradox consists, that two absolute unequal 
forces, but which have the quantities of motion equal, must stop each 
other because this happens in a relative action where the contest 
takes place only according to the quantities of motion infinitely small 
continually repeated. 

Now it is found by reason and by experiment, that it is living abso- 
lute force, or that which is estimated by the violent effect it can pro- 
duce, which is preserved, and nowise the quantity of motion. For if 
this living force could ever be augmented, the effect would be more 

1 The French text reads : " Cependant il est remarquable et a contribuer a 
l'erreur," etc. The reading should be: ".et a contribue," etc. — Ta. 



APPENDIX 661 

powerful than the cause, or rather the perpetual mechanical motion, 
that is to say, which could reproduce its cause and something more, 
which is absurd. But if the force could be diminished, it would perish 
at last entirely ; for never being able to increase, and being able never- 
theless to diminish, it would always go more and more into decay, which 
is without doubt contrary to the order of things. Experiment con- 
firms it also, and we shall find always that if bodies should convert 
their horizontal into ascending motions, they could always raise on 
the whole the same weight to the same height before or after the 
impact, supposing that no force has been absorbed in the impact by 
the parts of the bodies, when these bodies are not perfectly elastic, 
without speaking of that which the medium, the base, and other cir- 
cumstances absorb. But as this is a thing which I have sufficiently 
explained before, I will not repeat it here. 

Now I am very happy to give still another turn to the matter and 
to show further the conservation of something approaching more the 
quantity of motion, namely, the conservation of moving action (faction 
motrice). Here then is the general rule that I establish. Whatever 
changes may take place between concurrent bodies, of whatever num- 
ber, there must always be in the concurring bodies between themselves alone 
the same quantity of moving action in one and the same interval of time. 
For example, there must be during this hour as much moving action 
in the universe or in the given bodies, acting between themselves 
alone, as there will be during any other hour whatever. 

To understand this rule, it is necessary to explain the estimate of 
moving action (T action motrice), wholly different from the quantity 
of motion, in the manner that the quantity of motion has been 
wont to be understood as has been explained above. Now in 
order that the moving action may be estimated, we must first esti- 
mate the formal effect of motion. This formal or essential effect of 
motion consists in that which is changed by the motion, namely, in 
the quantity of the mass which is transferred, and in the space or in 
the length through which this mass is transferred. There is the 
essential effect of motion, or that which finds itself changed : for this 
body was there, now it is here : the body is so much and the distance 
is so much. I conceive in order to greater facility that the body is 
moved so that each point describes a straight line equal and parallel 
to that of every other point of the same body. I mean also a motion 
uniform and continuous. This assumed, the formal effect of motion 
is the product of the mass which is transferred multiplied by the 
length of the removal, or rather the formal effects are in reason com- 
posed of the masses and the lengths of the removal, so that a body, as 
2, being transported the length of 3 feet, and another body, as 3, being 
transported the length of 2 feet, the formal effects are equal. It is 
necessary carefully to distinguish what I here call the formal effect, or 



LEIBNITZ'S CEITIQUE OF LOCKE 



that essential to motion, from that which I called above the violent 
effect. For the violent effect consumes the force and is exercised 
upon something without ; but the formal effect consists in the body in 
motion, taken in itself, and does not consume the force, and even 
conserves it rather, since the same translation of the same mass must 
always be continued, if nothing from without prevents ; it is for this 
reason that the absolute forces are as the violent effects which con- 
sume them, but nowise as the formal effects. 

Now it will be easier to understand what moving action (Taction 
motriee') is : it must then be estimated not only by the formal effect 
which it produces, but also by the vigor or velocity with which it pro- 
duces it. We wish to transport 100 pounds to a distant place ; that 
is the formal effect which is demanded. One desires to do it in one 
hour, another in two hours ; I say that the action of the first is double 
that of the second, being doubly quick with reference to an equal 
effect. I suppose always continual and uniform motion. We may 
say also that a body, as 3, being transported the length of 5 feet, in 15 
minutes, is the same action as if a body, as 1, were transported the 
length of one foot in one minute. 

This definition of moving action (Taction motriee) is justified suffi- 
ciently a priori because it is manifest that in a purely formal action 
taken by itself, as is here that of a moving body considered by itself, 
there are two points to examine, — the formal effect or that which is 
changed, and the promptness of the change ; for it is very manifest 
that that which produces the same formal effect in less time is the 
more active. But if any one is obstinately bent upon disputing with 
me this definition of moving action, it would suffice me to say that I 
am free to call moving action what I just explained, provided that 
nature justifies afterwards the reality of this nominal definition, which 
will be when I shall show that it is precisely this whose quantity 
nature conserves. 

Now since moving action is that which comes by multiplying the 
formal effect by the velocity, I wish to give, more distinctly the esti- 
mate of velocity. We know that when two movable bodies run over 
uniformly the same space in unequal times, the velocity of that one 
which runs over it in less time will be the greater, in proportion as the 
time is shorter. Thus the spaces gone over being equal, the velocities 
are reciprocally proportional to the times. But if the times were 
equal, the velocities would be as the spaces gone over. For one body 
in motion having gone over a foot in one minute, and the other two 
feet, it is manifest that the velocity of the second is double. Thus 
the velocities are in reason composed of the direct of the spaces gone 
over and of the reciprocal of the times employed. Or what is the 
same thing, to estimate the velocity, we must take the space and 
divide it by the time. For example, A accomplishes 4 feet in 8 



APPENDIX 



663 



seconds and B 2 feet in 1 second; the velocity of A will be as 4 
divided by 8, namely as f- , and the velocity of B will be as 2 divided 
by 1, namely as 2, so that the velocity of A will be to that of B as f to 
2, that is to say, as 2 to 3. 

Now the question is to verify the conservation of the moving action 
(l' action motrice). I can give its general demonstration in a few 
words, because I have already proved elsewhere that the same force is 
conserved, and because at bottom the exercise of force or the force 
taken at the time is action, the abstract nature of force consisting 
only in that. Thus since the same force is conserved, and since action 
is the product of the force by the time, the same action will be con- 
served in equal times. But I wish to verify it by the detail of the laws 
of motion established by experiment and commonly received. I shall 
content myself with one example ; but we shall find it the same in 
every other example we might choose. And indeed we could see at 
once the general reason of it, by making the calculation in abstracto, or 
in general and by letters, without employing any particular numbers. 
But to suit the intelligence of everybody I prefer to give an example 
in numbers. 

Let there be a right angle LMN (Fig. 3), whose sides LM,MN may 




4 C 3 C a E 



Fig. 



iE 4 E 



be prolonged at discretion. Let a straight line AM be taken, so that 
prolonged beyond the point M it would cut the angle LMN into two 
equal parts. We might consider X AM as the hypotenuse of a square 
whose side may be called 1. This being so, I suppose that the body, A, 1 



1 We take no account here of the thickness of the hodies, which we suppose 
inconsiderable. — Leibnitz's Note. 



LEIBNITZ'S CRITIQUE OE LOCKE 



being in the place ^4 at the moment 1, A goes from the point X A to the 
point M, during the time 1, 2, and there meets at the moment 2 the 
two bodies B and C, which had been in repose during the 1, 2, which 
is known in the figure in that their place is designated by 4 B and by 
2 B, as also by X C and by 2 C. Now the body A meeting the two bodies 
in M at the moment 2, being in M ox 2 A, will drive them forward and 
come to rest in M, a point which will also be 3 A and 4 A, because A will 
remain there during the times 2, 8 and 3, 4, as I suppose the two 
mutually equal, and to the times 1, 2. But B will go towards L from 
the moment 2 during the time 2, 3 with a velocity as 1, and will meet 
at the moment 3 the body D, which had before gone in front of it 
during the times 1, 2, from the place X D to the place 2 D, and during 
the times 2, 3, from the place 2 D to the place 3 D, with a velocity as £. 
Now B, meeting D at the moment 3, will give it the velocity 3 -D 4 i); 
that is to say, in the times 3, 4, X D will reach 4 D, and during that 
time, B will go from 3 B to 4 B with the velocity 3 1> 4 -B. It will be the 
same on the other side, where C, pushed by A in the moment 2, will 
go towards N with the velocity 1, and will meet, at the moment 3, the 
body E, which goes against it, having gone before, during the times 1, 2, 
from the place X E to the place 2 E, and during the times 2, 3 from the 
place 2 E to the place Z E, with a velocity as §. Now C, meeting E at 
the moment 3, will give it the velocity 3 E 4 E; that is to say, that in 
the times 3, 4, it comes from 3 E to 4 £J. And during this time, C will 
go from 3 C to 4 C with the velocity ^C^. 

The register of the masses and velocities follows. 

The masses of the bodies A, B, C, D, E are 1, 1, 1, 2, J. 

During the times 1, 2 the velocities of the bodies A, B, C, D, E are 
V2, 0, 0, i, f . 

During the times 2, 3 the velocities of the bodies A, B, C, D, E 
are 0, 1, 1, £, f . 

During the times 3, 4 the velocities of the bodies A, B, C, D, E 
are 0, J, I, f , ^, where it is to be remarked that the body C, instead 
of advancing, reflects backward with the velocity |. 

The justification of these numbers will be found in the rules 
or equations which we shall assign farther on. 

Let us now make the calculation of the moving actions (actions 
moll-ices') during the times equal between them — 1, 2 ; 2, 3 ; 3, 4. 
During the times 1, 2. 

A is in mass 1, the length of the transfer X A A is ^/2. Then 
multiplying one by the other, the formal effect is y/2. The 
velocity comes from dividing the length ^/2 by the time 1, which 
makes y/2. And multiplying the effect by the velocity, the moving 
action is 2. 

B and C are at rest during this time in X B, 2 B, or X C, 2 C, conse- 
quently their moving action is 0. 



APPENDIX 665 

D is in mass 2, the length of the transfer J, the formal effect 
2 by £ or 1. The length J being divided by the time 1, the velocity £ 
arises, and the effect multiplied by the velocity is 1 by J, or J, which 
is the action of D. 

E is in mass J, the length of the transfer f, consequently the 
effect A. Now the length f divided by 1 gives the velocity f, which, 
multiplied by the effect, furnishes f the action of E. 

And the sum of all the moving actions of the bodies A, B, C, D, 
E, during the times 1, 2, is 2 + + + J + } = ff . 
During the times 2, 3. 

A is at rest, and its action is 0. 

B is in mass 1, the length of the transfer 1 (namely, 2 B S B), the 
formal effect 1 ; the length 1 divided by the time 1 gives the velocity 
1, which, being multiplied by the effect 1, 1 arises, which is the action 
of B. 

C ; the calculation is the same in regard to C and there arises the 
same action 1. 

D has the same action as in the preceding time ; namely, £. 

E likewise has the same action as in the preceding time ; namely, J. 

And the sum of all the moving actions of the bodies A, B, C, D, E, 
during the times 2, 3, is + 1 + 1 + J + f = ft> as before. 
Finally, during the time 3, 4. 

A is at rest, and its action is 0. 

B is in mass 1, the length of the transfer, namely, S B 4 B, is |, conse- 
quently the effect is a. The same length, I, divided by the time 1, 
gives \ for the velocity, which multiplied by the effect, \ arises, the 
action of B. 

C is in mass 1, the length of the transfer 3 C 4 C is |, consequently 
the formal effect is \. For it matters not here when we seek absolute 
things, whether C advances by s C t C, or reflects backward, as it does 
in fact. The same length, i, divided by the time 1 gives the velocity -*-, 
which, multiplied by the effect, there arises J T as the action of C. 

D is in mass 2, the length of the transfer ^DJ) is f , consequently 
the effect is f . The same length divided by the time 1 is f, or the 
velocity, which multiplied by the effect, there arises ff, which is the 
action of D. 

E is in mass J, the length of the transfer is - 1 /, the effect J. The 
same length divided by the time 1 is -^, that is to say, the velocity, 
which, multiplied by the effect, produces f f for the action of E. 

And the sum of all the moving actions of the bodies A, B, C, D, E, 
during the time 3, 4, is 

■ 1 . 1 .25 98 _ 18 + 2 + 225 + 196 _ 441 _ 49 
' 9 81 18 81. 162 ~162 _ 18' 

as in each one of the preceding times. 



LEIBNITZ'S CRITIQUE OF LOCKE 



I have followed in this calculation the general method, for as the 
moving actions are not only equal in equal times, but proportional to 
the times in unequal times, I have divided the space by the time, in 
order to have the velocity ; but when the time is always the same, as 
here, and thus we can take it as unity, the division by the time changes 
nothing, and consequently for the velocity we can take the number of 
the length of the transfer, the velocities being as the spaces : whence 
it is manifest that the effect being the product of the mass and the 
space, and the velocity being as the space, the action is as the product 
of the mass by the square of the space of the transfer (we mean a 
horizontal transfer in falling bodies), or as the product of the mass by 
the square of the velocity. Now, I shall prove, further on, in the 3d 
equation, that the sum of these products of the masses by the squares 
of the velocities is conserved in the concourse of the bodies. Con- 
sequently, it is proved that the moving action is conserved, without 
speaking of other proofs by which I have shown elsewhere that the 
forces are conserved, and that the forces are as the products of the 
masses by the squares of the velocities, while the actions are as 
the products of the forces by the times, so that if we did not know 
elsewhere this estimate and conservation of force, we might learn it 
here, in finding by the calculation in detail, or even in general, by the 
3d equation, further on, that the moving action is conserved ; now it 
is clear that the moving actions are in reason composed of the forces 
and the times, and the times being the same, the moving actions are 
as the powers or forces. 

But shall we be astonished whence comes this success, which will 
never fail, however intricate may be the example which we may 
choose? It may be proved a priori, independently of the rules of 
motion received ; and this is what I have shown many times in dif- 
ferent ways. But here I shall show that it is proved by these very 
rules of percussion which experience has justified, and whose rationale 
we may give by the method of a boat, as Huygens has done, and in 
many other ways, although we are always obliged to assume something 
non-mathematical, which has its source higher. But I shall reduce 
the whole to three equations very simple and beautiful, and which 
contain all which concerns the central concourse of two bodies in one 
and the same straight line. 

Conspiring velocities 
of the body a before the impact v after x, 
b y z. 

I call these conspiring velocities, because I suppose they all tend from 
the side whence proceeds the centre of gravity common to the two 
bodies. But if perchance any velocity proceeds really in the contrary 
direction, then the letter which expresses the conspiring velocity sig- 
nifies a negative quantity. But we shall always take the body a as a 



APPENDIX 667 

body whose velocity is really conspiring, or proceeds from the side of 
the centre of gravity before the impact, and also in such a manner 
that the body a follows and does not precede the common centre of 
gravity. Thus the signs do not vary in v, but they may vary in y, z, x. 
Here, now, are our three equations : — 

I. Lineal equation, which expresses the conservation of the cause 
of the impact, or of the relative velocity 

v - y = z - x, 

and v — y signifies the relative velocity between the bodies before the 
impact with which they approach, and z — x signifies the relative 
velocity with which they depart after the impact. And this relative 
velocity is always the same in quantity before or after the impact, 
supposing that the bodies are very elastic, which this equation states. 
It is necessary only to remark that while the signs vary in the explica- 
tion of the detail, this general rule will embrace all the particular 
cases. This also occurs in the following equation : — 

II. Plane equation, which expresses the conservation of the common 
or total progress of the two bodies 

av + by = ax + bz. 

I call progress here the quantity of motion which proceeds from the 
side of the centre of gravity, so that if the body b, for example, should 
proceed in the contrary dh-ection before the impact, and thus its con- 
spiring velocity y be negative or be expressed by —(?/), understand- 
ing by (y) mass (?nolem), or that which is positive in y, then the 
progress of a will be av, the progress of b will be —b(y). And the 
total progress will be av — b(y), which is the difference of the quanti- 
ties of motion of the two bodies. If the bodies a and b proceed from 
one and the same side before and after the impact, these letters, v, y, 
x, z, signify only conspiring velocities real or affirmative, and conse- 
quently in this case it appears by this equation that the same quantity 
of motion will be conserved after and before the impact. But if the 
bodies a and b should proceed in a contrary direction before the 
impact and in the same direction after the impact, the difference of 
the quantity of motion before the impact would be equal to the sum 
of the quantity of motion after the impact. And there will be other 
similar variations according to the variation of the signs of the letters 
y, x, z. 

III. Solid equation, which expresses the conservation of the total 
absolute force or of the moving action 

qvv + byy = axx + bzz. 

This equation has this excellence, that all the variations of the signs 
which can arise only from the diverse direction of the velocities y, x, 
z, y cease, by the fact that all the letters which express these veloci- 



LEIBNITZ'S CRITIQUE OF LOCKE 



ties mount here to the square. Now — y and + y have the same 
square + yy, so that all these different directions of y produce noth- 
ing more. And it is also for that reason that this equation gives 
something absolute, independent of the relative velocities, or of the 
progressions from a certain side. The question here concerns only the 
estimating of masses and velocities, without troubling ourselves from 
what side these velocities arise. And this it is which satisfies at the 
same time the rigor of the mathematicians and the wish of the philoso- 
phers, — the experiments and reasons drawn from different principles. 
Although I put together these three equations for the sake of beauty 
and harmony, nevertheless two of them might suffice for our needs. 
For, taking any two of these equations, we can infer from them 
the remaining one. Thus, the first and the second give the third 
in the following manner. By the first, we shall have v + x= y + z; 
by the second, we shall have a, v — x = b, z — y; and, multiplying one 
equation by the other, according to the corresponding sides, we shall 
have a, v — x, v + x = b, z — y, z + y, which makes aw — axx = bzz — byy, 
or the third equation. In the same way, the first and the third give 
the second ; for a, vv — xx — b, zz — yy, which is the third, divided by 
the first v + x = z + y, side by side, we shall have a, vv — xx, :,v + x = b, 
zz — yy, :, z + y, which makes a, v — x — b, z — y, that is, the second 
equation. Finally, the second and the third equation give the first. 
For the third a, vv — xx = b, zz — yy divided by the second, namely, 
by a, v — x — b, z — y, gives 

a, vv — xx _ b, zz — yy 
a, v-x b,z-y' 

which makes v + x = z + y, according to the first equation. 

I would add only one remark, which is that many distinguish 
between hard and soft bodies, and the hard themselves as elastic 
or not, and build thereupon different rules. But we may take bodies 
naturally as hard-elastic, without however denying that the elas- 
ticity must always come from a fluid more subtile and penetrating, 
whose motion is disturbed by the tension or by the change of the 
elasticity. And as this fluid must be composed itself in its turn of 
little solid bodies, elastic between themselves, we see well that this 
replication of solids and of fluids continues to infinity. Now this 
elasticity of bodies is necessary to nature, in order to obtain the 
execution of the grand and beautiful laws which its infinitely wise 
author has proposed, among which not the least are these two laws 
of nature which I first made known, the first of which is the law 
of the conservation of absolute force or of moving action in the uni- 
verse, with some other absolutely new conservations which depend 
upon it and which I will explain some day, and the second is the 
law of continuity, in virtue of which, among other effects, every change 



APPENDIX 



must take place through inassignable passages and never by a leap. 
This also is the reason why nature suffers no hard non-elastic 
bodies. In order to show this, -let us pretend that a hard non-elastic 
globe proceeds to strike against a similar globe at rest : after the 
impact it is necessary that the two globes rest, in which case the 
law of the conservation of force is violated, or that there be some 
motion and that the globe which was at rest receive it, being unable 
to be taken as immovable, although even if it should feign to be 
such, the striking body (in order to preserve the force) would nec- 
essarily be reflected suddenly backward. This is a forbidden (defendu) 
change, since it would be by a leap, a body which proceeds from a 
certain side being obliged to abate its motion, even to rest, before 
beginning to proceed gradually further and further backward. But 
the globe which is struck being obliged to receive motion, there 
will also be a change by a leap, the struck globe which was at rest 
being obliged to receive a certain degree of velocity suddenly, not 
being pliable so as to receive it gradually and by degrees. It being 
also manifest, as is necessary, either that the globe striking passes 
suddenly to rest, which would be already a change by a leap, or that 
if this striking globe retains a certain velocity, the struck globe which 
was at rest receives suddenly an amount which is not less than that 
of the striking globe, since the globe struck must either stop the 
striking globe, or go before it. Thus the striking globe passes 
suddenly from velocity to rest, or at least the struck globe passes 
suddenly from rest to a certain degree of velocity, without passing 
through the intermediate degrees, which is contrary to the law of 
continuity, which admits no change by a leap in nature. I have also 
many other reasons all of which concur in banishing hard non-elastic 
bodies, but this is not the place to enlarge upon them. 

But it is necessary to admit, that although bodies must be thus 
naturally elastic in the sense which I have just explained, nevertheless 
the elasticity often appears insufficient in the masses or bodies which 
we employ, even if these masses should be composed of elastic parts 
and should resemble a sack full of hard balls which would yield to a 
moderate impact, without leaving the sack, as we see in the case of soft 
bodies or those which yield without recovering themselves sufficiently. 
The reason is that the parts are not sufficiently united therein to trans- 
fer their change to the whole. Whence it comes that in the impact of 
such bodies a part of the force is absorbed by the small parts which 
compose the mass, without this force being given to the whole ; and 
this must always happen when the pressed mass does not recover per- 
fectly; although it also happens that a mass shows itself more or less 
elastic according .to the different manner of the impact, witness the 
water itself which yields to a moderate impression, and makes a can- 
non-ball rebound. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Now when the parts of the bodies absorb the force of the impact, as 
a whole, as when two pieces of rich earth or of clay come into collision, 
or in part, as when two wooden balls meet, which are much less elastic 
than two globes of jasper or tempered steel ; when, I say, some force is 
absorbed by the parts, it is as good as lost for the absolute force, and 
for the respective velocity, that is to say, for the third and the first 
equation, which do not succeed, since that which remains after the 
impact has become less than what it was before the impact, by reason 
of a part of the force being turned elsewhere. But the quantity of prog- 
ress, or rather the second equation, is not concerned therein. And 
even the motion of this total progress remains alone, when the two 
bodies proceed together after the impact with the velocity of their com- 
mon centre, as do two balls of rich earth or clay. But in the semi- 
elastics, as two wooden balls, it happens still further that the bodies 
mutually depart after the impact, although with a weakening of the 
first equation, following this force of the impact which has not been 
absorbed. And in consequence of certain experiments touching the 
degree of: the elasticity of this wood, we might predict what should 
happen to the balls which should be made of it in every kind of col- 
lision or impact. But this loss of the total force, or this failure of the 
third equation, does not detract from the inviolable truth of the law 
of the conservation of the same force in the world. For that which 
is absorbed by the minute parts is not absolutely lost for the universe, 
although it is lost for the total force of the concurrent bodies. 



ESSAY ON DYNAMICS IN DEFENCE OF THE WONDER- 
FUL LAWS OF NATURE IN RESPECT TO THE FORCES 
OF BODIES, DISCLOSING THEIR MUTUAL ACTIONS 
AND REFERRING THEM TO THEIR CAUSES 1 

[From the Latin] 

Part I 

From the time we made mention of the founding of a New Science 
of Dynamics, many distinguished men in various places have asked 
for a fuller explication of this doctrine. Since, therefore, we have not 

iGerhardt, Leibniz, math. Schrift., II., 2 [Vol. 6], pp. 234-246. Dutens, 
Leibnit. op. om., 3, 315-324. First published in the " Acta Eruditor. Lips.," in 
April, 1695. — Tr. 



APPENDIX 671 



yet leisure to compose the book, 1 we will give in this place those things 
which may kindle some light, which perhaps will return to us with 
interest, if, indeed, we shall elicit the opinions of those who unite 
energy of thought with elegance of speech, whose judgments also we 
openly confess will be acceptable to us, and we hope useful in the set- 
ting forward of the work. We have elsewhere suggested that there 
is in corporeal things something besides extension, nay, prior to ex- 
tension, namely, the force itself of nature everywhere implanted by its 
Author, which consists, not in the simple faculty with which the schools 
seem to have been content, but, besides, is provided with a tendency 
(conatu) or effort (nisu) which will have its full effect unless impeded 
by a contrary tendency (conatu). This effort often appears to the 
senses, and in my judgment is known everywhere in matter by the 
reason, even when it does not appear to the sense. But if now this 
force must not be assigned to God through a miracle, it is certainly 
necessary that this force in bodies themselves be produced from the 
body itself, nay, that it constitute the inmost nature of bodies, since 
to act is a mark of substances, and extension means nothing else than 
the continuation or diffusion of the already presupposed struggling 
and withstanding, that is, resisting substance, so far is it from 
being itself able to produce substance. Nor is it necessary, because 
every corporeal action arises (est) from motion, and motion itself does 
not exist unless from motion, either in the body already before exist- 
ing or impressed from something external to it (aliunde). For 
motion (just as time) never exists, if you reduce the thing to axpi- 
(3aav, because a whole never exists, when it has not coexisting parts. 
And nothing is so real in itself, as that momentary increment (momen- 
taneum) which must be constituted in a force striving for change. To 
this, therefore, returns whatever there is in corporeal nature besides 
the object of geometry or extension. And by this method, in fact, 
regard is had at the same time for both the truth and the doctrine of 
the ancients. And as our age has freed from contempt the atoms of 
Democritus, the ideas of Plato, and the tranquillity of the Stoics in the 
best nexus of things, so now the traditions of the Peripatetics concern- 
ing forms or entelechies (which deservedly seemed enigmatical and 
scarcely rightly perceived by the authors themselves) will be referred 
to intelligible notions, so that we think it necessary rather to explain 
the philosophy thus received by so many ages, so that it may be con- 
sistent (where this is permitted) and to illustrate and then increase 
it with new truths, than to destroy it. 

And this kind of studies seems to me especially suited both to the 
intelligence (prudential) of the teacher and to the profit of the learners, 

1 For the work referred to, cf. Gerhardt, Leibniz, math. Schrift., II., 2 
[\ T ol. 6], pp. 281 sq. — Tk. 



LEIBNITZ'S CRITIQUE OF LOCKE 



so that we may not seem more desirous of destroying than of building, 
nor be tossed between perpetual changes of doctrine, daily uncertain 
because of the pride of audacious geniuses, but at length the human 
race, the lust of sects being curbed (which the inane glory of change 
[novaniW] stimulates), the certain dogmas established, without stum- 
bling, not less in philosophy than in mathematics, will make further 
advance, since in the writings of distinguished men, ancient and mod- 
ern (if you take away entirely those things in which they speak too 
severely against others), there is wont to be very much that is true and 
good, which deserves to be rescued and to be distributed into the pub- 
lic treasury. And would that men preferred to do this rather than 
spend their time in censures by which they only appease their own 
vanity. But somehow very many even hostile views do not displease 
us certainly, whom fortune has so favored in certain new views of ours, 
that friends often bade us think of these only, and each view is 
considered according to its own value, although diverse ; the reason 
of which perhaps is that in discussing many things we have learned 
to despise nothing. But now let us return to our subject. 

A dive force (which with some you call not ill power — virtus) is two- 
fold, namely primitive, which exists in every corporeal substance per se 
(since I think a wholly quiescent body abhorrent to the nature of 
things), or derivative, which by a limitation as it were of the primi- 
tive, resulting through the conflicts of bodies with each other, is vari- 
ously exercised. And the primitive force indeed (which is nothing 
else than evreAe^eta r/ irputrrj) corresponds to the substantial soul or 
form, but indeed for this reason pertains only to general causes, which 
cannot suffice for the explanation of phenomena. And so we agree 
with those who deny that forms must be employed in handing down 
the particular and special causes of sensible things : to point out 
which is worth while, lest, while we lead them as it were back again 
to the open fountains of things, at the same time we seem to desire 
to return to the 'vain repetitions' (battologias) of the vulgar school. 
Meanwhile a knowledge of them is necessary to correct philosophiz- 
ing, nor may any one think he is master of the nature of body, unless 
he has turned his mind to such things and understood that that crass 
notion of corporeal substance is imperfect, not to say false, and 
depends upon the imagination alone and was introduced inconsider- 
ately some years since by an abuse of the corpuscular philosophy (in 
itself excellent and most true), as indeed is evident by this argument 
which does not entirely exclude cessation and rest from matter, and 
cannot bring forward reasons for the laws controlling the derivative 
force of nature. In like manner passive force also is twofold, either 
primitive or derivative. And indeed the primitive force of enduring or 
resisting constitutes that very thing which is called primary matter, if 
you rightly interpret it, in the schools, by which it happens that body 



APPENDIX 673 



is not penetrated by body, but forms an obstacle to it, and it is en- 
dowed at the same time with a certain laziness, so to speak, that is, 
repugnance to motion, and does not indeed suffer itself to be set in 
motion unless by the somewhat broken force of the active body. 
Whence afterwards the derivative force of enduring variously exhibits 
itself in secondary matter. But it is our part now to proceed farther, 
having removed those general and primitive forces and substituted 
those by which we are taught that because of form every body always 
acts and because of matter every body always endures and resists, 
and in this doctrine of derivative forces and resistances to investigate 
how far bodies prevail by various efforts or again variously resist ; for 
the laws of actions, which are known not only by reason, but are 
confirmed also by sense itself through phenomena, are adapted to 
these. 

Derivative force therefore, by which bodies in action act mutu- 
ally on each other or mutually suffer from each other, we under- 
stand in this place as no other than that which is connected with 
motion (i.e. local), and in turn tends to produce further local 
motion. For we admit that through local motion other material 
phenomena can be explained. Motion is a continual change of 
place, and thus requires time. Yet the movable element (mobile) 
existing in motion, as it has motion in time, so in any moment 
whatever has velocity, which is so much the greater as more space 
is run over and less time is expended. Velocity taken in connection 
with direction is called conatus ; but impetus is the product of the mass 
of the body into the velocity, and its quantity is so much that the 
Cartesians are wont to call it the quantity of motion, namely, the mo- 
mentary increment (rnomentaneani) , although, speaking more accurately, 
the quantity of motion itself, existing forsooth in time, arises from the 
aggregate of the impetuses (equal or unequal) existing in the mov- 
able element in the given time multiplied in order into the time. We, 
nevertheless, in discussing with these have followed their fashion of 
speaking. Nay even as (not inconveniently for the doctrinal use of 
speaking) we can distinguish the accession which now is made from 
the accession already made or to be made, as an increment of accession 
or element ; or as we may distinguish the present descent from the 
descent already made, which it increases ; so we can discern and call 
Motion the momentary or instantaneous element of motion diffused by 
the motion itself through a period of time ; and so that which is com- 
monly ascribed to motion is called the quantity of motion. And although 
in the use of terms we are compliant (faciles) in accord with an ac- 
cepted interpretation, nevertheless it especially behooves us to be care- 
ful in their use lest we be caught by their ambiguity. 

Moreover, as the estimate of motion through a period of time is 
made from infinite impulses, so in turn the impulse itself (although 
2x 



LEIBNITZ'S CRITIQUE OF LOCKE 




a momentary thing) is made from infinite degrees successively im- 
pressed upon that same movable body (mobile), and has a certain ele- 
ment from which, unfolded, nothing but infinity can arise. 

Conceive a tube AC (Fig. 4) to revolve with a certain fixed uniform 
velocity in the horizontal plane of this page about an immovable 
centre C, and a ball B, existing in the cavity of 
the tube, to be freed from its chain or impediment, 
= - . . and to begin to be moved by the centrifugal force ; 
' it is manifest that the attempt in the beginning 
to depart from the centre by which, namely, the 
ball in the tube tends towards its extremity A, is 
infinitely small in respect to the impulse which it 
already has from the rotation, or by which with 
the tube itself, the ball B tends from the place 
D towards (D), its distance from the centre being- 
retained. But with the continuance for some time 
Fig. 4. of the centrifugal impression proceeding from the 

rotation, from its own progress there must arise in 
the ball a certain complete centrifugal impulse (D)(B), comparable 
with the impulse of rotation D(D). Hence it is evident that the 
effort is twofold, elementary to be sure, or infinitely small, which I 
call, also, solicitation, and formed by the continuation or repetition 
of elementary efforts ; that is, the impulse (impetum) itself, although 
I do not, for that reason, mean that these mathematical entities are 
really so found in nature, but only that they are useful in making- 
accurate estimates by mental abstraction. 

Hence force also is twofold : the one elementary, which I call also 
dead, because motion (motus) does not yet exist in it, but only 
a solicitation to motion (solicitatio ad motum), such as that of the 
ball in the tube, or of the stone in the sling, even while it is held 
still by the chain ; the other, however, is ordinary force, united with 
actual motion, which I call living. And an example of dead force 
indeed is the centrifugal force itself, and likewise the force of gravity 
or centripetal force, the force also by which the tense elastic body 
(elastrum) begins to restore itself. But in percussion, which arises 
from a heavy body falling already for some time, or from a bow 
restoring itself for some time, or from a similar cause, the force 
is living force, which has arisen from an infinite number of con- 
tinued impressions of dead force. And this is what Galileo meant, 
when in his enigmatical manner of speaking he spoke of the 
infinite force of percussion, namely if compared with the simple 
effort of gravity. But although the impulse (impetus) is always 
united with living force, yet we shall show below that these two are 
different. 

Living force in any aggregate of bodies again can be known as 



APPENDIX 675 



twofold, namely total, or partial; and partial again is either re- 
spective or directive, that is, either proper or common to the parts. 
Respective (respectiva) or proper (propria) force is that by which the 
bodies comprised in the aggregate can act among themselves mutually ; 
directive or common force is that by which, besides, this aggregate 
can act outside itself. But I call it direct, because the total force 
of direction is preserved intact in this partial force. But this alone 
would remain, if suddenly the aggregate were imagined to congeal 
by the intercepted motion of its parts among themselves. Whence 
from respective and directive taken together total absolute force is 
composed. But these things will be better understood from the 
rules to be propounded below. 

The ancients, as far as known, had a science of dead force 
alone, and this it is which is commonly called Mechanics, treating 
of the lever, block, inclined plane (where belongs the wedge and the 
spiral), the equilibrium of liquids, and similar things, in which they 
treat in turn only of the first tendency (conatu) of the bodies among 
themselves, before they received an impulse by acting. And although 
the laws of dead force can in some fashion be transferred to living 
force, yet there is need of great caution, as even they may have been 
deceived, for this reason, who confounded force in general with the 
quantity produced by the multiplication of the mass into the 
velocity, because they understood that force is dead in the regular 
theory of these. For this thing happens there for a special reason, 
as we already long ago suggested, since (for example), in dif- 
ferent descending weights, in the very beginning of motion at 
least the descents themselves or the quantities of the spaces gone 
through in the descent, certainly infinitely small or elementary 
hitherto, are proportional to the velocities or to the efforts to descend. 
But the progress being made and living force having arisen, the 
acquired velocities are no longer proportional to the spaces already 
run over in the descent, by which, nevertheless, we have shown 
formerly and shall further show, that the force must be estimated, 
but only to the elements of these velocities. Galileo began to 
discuss concerning living force (although under another name, nay, 
I should rather say, concept) and was the first to explain how by 
the acceleration of descending weights motion arises. Descartes 
rightly distinguished velocity from direction, and saw even in the 
conflict of bodies that follow by which the former conditions are 
least changed. But he did not rightly estimate the least change, 
while he changes the direction alone or the velocity alone, since 
the change moderated by mixing would be obtained from both : 
but how this must come about escaped him, because to hiin, intent 
at that time upon modal manifestations rather than upon realities, 
phenomena so heterogeneous did not seem capable of being compared 



676 LEIBNITZ'S CRITIQUE OF LOCKE 

and modified by union, so that we shall say no more of his other 
errors in this doctrine. 

Honoratus Fabri, 1 Marcus Marci, 2 Joh. Alph. Borellus, 3 Ignatius 
Baptista Pardies, 4 and Claudius de Chales, 5 and other men very acute 
in learning have published things not to be despised on motion, but 
nevertheless have not shunned these capital errors. Huygens, 6 the 
first that I know who has adorned our age with splendid discoveries, 
seems to me in this argument also to have reached the pure and un- 
adulterated truth and to have freed this doctrine from paralogisms, 

i Cf. ante, p. 586, note 2.— Tr. 

2 Johannes Marcus Marci von Kronland, 1595-1667, a German physician, 
mathematician, and physicist, published his De proportione motus, seu regula 
sphygmica ad celeritatem et tarclitatem pulsuum, ex illius motu ponderibus 
geornetricis librato, absque errore metiendam, Pragse, 1639, a remarkable 
work on the theory of impact, preceding by thirty years the researches of 
Wallis, Wren, and Huygens. This is probably the work to which Leibnitz 
here refers. — Tr. 

3 Giovanni Alfonso Borelli, 1608-1679, a distinguished Italian physician and 
mathematician, the founder of the iatromathematical theory of medicine, was 
Professor of Mathematics at Pisa and Naples. He was the author of seA r eral 
medical and mathematical works, among which were Theorica mediceorum 
planetarum ex causis physicis deducta, Florent., 1666; De motu animalium, 
Rome, 1680-1681; De vi percussionis, Lugd. Bat., 1686; and De Motionibus 
naturalibus, a gravitate pendentibus, Lugd. Bat., 1686. The two latter works 
are probably the ones referred to by Leibnitz. For an account of his views, 
cf. Lasswitz, Gesch. d. Atomistik, Hamburg u. Leipzig, 1890, Vol. 2, pp. 300-328. 
— Tr. 

4 Iguace Gaston Pardies, 1636-1673, a French Jesuit and geometer, was 
Professor of Philosophy, and afterwards of Mathematics, at Paris. In his 
correspondence with Newton, he sought to explain the dispersion of light as 
a diffraction by aid of the assumption that the transmission of light depends 
upon a wave-movement. He intended to write a great work on Mechanics, of 
which only Pts. 1 and 2, Discours du mouvement local, Paris, 1670, and La 
statique ou la science des forces mouvantes, Paris, 1673, appeared. His (Euvres 
de mathematiques, etc., 4th ed., appeared a La Haye, 1710. Cf. Lasswitz, 
Gesch. d. Atomistik, 2, 340. Leibnitz refers to Pardies in a communication to 
H. Fabri, cf. Gerhardt, Leibniz, math. Schrift., II., 2 [Vol. 6], 81, 84; Gerhardt, 
Leibniz, philos. Schrift., 4, 244, 247. — Tr. 

5 Claude Francois Milliet Deschales, 1621-1678, a French Jesuit and dis- 
tinguished mathematician and physicist, published his C'ursus seu mundus 
mathematicus, 3 tomi, 1st ed., Lugduni, 1674, 2d ed., 1690. Leibnitz refers to 
him briefly in a communication to H. Fabri, Gerhardt, Leibniz. philos. Schrift., 
4, 245 ; Leibniz, math. Schrift., II., 2 [Vol. 6], 81. Brief account of his views 
is given in Lasswitz, Gesch. d. Atomistik, 2,487-490. — Tr. 

6 Cf. ante, p. 150, note 3. The doctrine of Huygens, here referred to, is found 
in his De motu corporum ex percussione (1669) , which was first published in 
1703 ; Opera reliqua, Amstel., 1728, Vol. 2 ; GEuvres completes, La Haye, 1888 sq. 
His correspondence with Leibnitz is found in Gerhardt, Leibniz, math. Schrift., 
I., 2 [Vol. 2], 1-208. References to the doctrine of motion occur on pp. 140, 
184. An account of Huygens' physical and mechanical views is given in Lass- 
witz, Gesch. d. Atomistik, 2, 341-397. — Tr. 



APPENDIX 677 



by certain rules formerly published. Wren x also, Wallis 2 and 
Mariotte, 3 men excellent in these studies though diverse in method, 
demonstrated nearly these same rules. But concerning the causes, 
nevertheless, opinion is not the same ; whence men distinguished in 
these studies do not always admit the same conclusions. And indeed 
the true sources of this science have not yet, as is evident, been dis- 
closed. Nor indeed is what seems certain to me admitted by all: 
that rebounding or reflection springs only from elastic force, that is, 
from internal resistance to motion. Nor has any one before us ex- 
plained the notion itself of forces, which thing hitherto has disturbed 
the Cartesians and others, who, even for this reason, could not com- 
prehend that the sum of the motion or impulse (which they regard 
as the quantity of the forces) can appear different after the encounter 
from before, because for this very reason they believed the quantity 
of the forces to be changed. 

From me, still a youth, and at that time constituting the nature of 
body, with Democritus and his adherents in this matter, Gassendi 
and Descartes, in inert mass alone, there escaped a little book 
" Hypothesis Physica " 4 by title, in which I set forth a theory of 
motion, at the same time abstract (abstractam) from the system and 
concrete (concretam) for the system, 5 which beyond the merit of its 

i Sir Christopher Wren, 1631-1723, best known as the architect of St. Paul's, 
London, was distinguished at Oxford for his knowledge of geometry and 
applied mathematics. In 16(30 he was elected Savilian Professor of Astronomy 
at Oxford. Newton, in his Principia, ed. 1713, p. 19, speaks highly of his 
work as a geometrician. Leibnitz refers to him in the Hypoth. phys., cf. 
Gerhardt, Leibniz, math. Schrift., II., 2 [Vol. 6], 26, 29, 30, 75 ; Philos. Schrift., 
4, 187,190, 191, 236. — Tr. 

2 John Wallis, 1616-1703, an eminent English mathematician, appointed 
Savilian Professor of Geometry, at Oxford, 1619, published his Mechanica, 
sive de Motu Tractatus Geometricus, 3 parts, 1669-1671. His complete works 
were published, Oxford, 1695-1699, 3 vols., fol. The correspondence between 
Leibnitz and Wallis is found in Vol. 3 of this ed., and also in Gerhardt, Leibniz, 
math. Schrift., I., 4 [Vol. 1], 1-82.— Tr. 

3 Cf. ante, p. 121, note 4. An elaborate treatise on the percussion of bodies, 
De la percussion ou choc des corps, probably the one to which Leibnitz here 
refers, is found in first volume of his CEuvres, Leyden, 1717. — Tr. 

4 Cf. Gerhardt, Leibniz, math. Schrift., II., 2 [Vol. 6], 17-80 ; Gerhardt, Leib- 
niz, philos. Schrift., 4, 177-240; Dutens, Leibnit. op. om., 2, Pt. II., 1-48. — Tr. 

5 The compressed and somewhat obscure text is explained by the titles of 
two essays forming the Hypothesis Physica nova. The title of the first essay 
is : Theoria motus concreti sen Hypothesis de rationibus phsenomenorum nostri 
Orbis ; that of the second is : Theoria motus abstracti seu Rationes motuum 
universales a sensu et phsenomenis independentes. Cf. Gerhardt's Einleitung, 
Leibniz, philos. Schrift., 4, 9-12, and especially the portion, there quoted, of 
a letter to Foucher, found also in op. cit., 1, 415 ; Erdmann, Leibnit. op. philos., 
117 ; F. de Careil, Lettres et Opuscides inedits de Leibniz, Paris, 1854, 119-120 ; 
Dutens, Leibnit. op. om.,2, Pt. I., 242 ; transl. Duncan, Philos. Wks. of L,eibnitz, 
64-65. — Tr. 



678 LEIBNITZ'S CRITIQUE OF LOCKE 

mediocrity I see has pleased many distinguished men. I there estab- 
lished, having assumed such a conception of body, the fact that every 
striking body gives its impulse (conatum) to the receiving or directly 
opposing body as such. For since, in the moment of attack, the 
receiving body undertakes to go forward and thus run away with 
itself, and that impulse (on account of the indifference then believed 
by me of the body to motion or rest) must have its effect wholly in 
the receiving body, unless hindered by a contrary impulse, nay, even 
if hindered by it, since it is so necessary that these different impulses 
should be adjusted among themselves ; it was manifest that no cause 
could be given why the striking body should not attain the effect 
towards which it tends, or why the receiving body should not receive 
the entire impulse of the striking body, and so the motion of the 
receiving body was composed of its own pristine impulse, and of the 
newly received or foreign impulse. From which then I was showing 
that if mathematical notions alone, — magnitude, figure, place, — and 
the change of these, or in the moment itself of impact (concursus) 
the impulses to change were perceived in the body, no theory of meta- 
physical notions being held, namely, of power active (actricis) in form 
and of inactivity (ignavice), or of resistance to motion in matter, and 
so if it were necessary for the concourse of events to be determined 
by the geometrical composition of impulses alone, as we have ex- 
plained : then it must follow that the impulse of the striking body, 
even the least, is impressed upon the entire receiving body, although 
the greatest, and so the greatest body at rest is dragged away by the 
striking body, however small, without any retardation of this body, 
since indeed no repugnance, but rather indifference of it to motion, 
is contained in such a notion of matter. Whence it would not be 
any more difficult to impel a large quiescent body than a small one, 
and thus there would be action without reaction, and there could be no 
estimate of power, since anything whatever could be proved by any- 
thing whatever. And since these things, and many others of the 
same kind, are opposed to the order of things and conflict with the 
principles of a true metaphysic, I thought at that time therefore (and 
indeed truly) that the most wise Author of things in the construction 
of the system shunned those things which would follow of themselves 
from the mere laws of motion derived from pure geometry. 

But afterwards, having examined things more deeply, I saw in 
what the systematic explanation of things consisted, and' regarded 
that former hypothesis of the notion of the body as incomplete, and 
both by other arguments and also by this itself it was proved that' in 
body there must be placed something besides magnitude and impene- 
trability, whence the consideration of forces arises, by adding the met- 
aphysical laws of which to the laws of extension those very rules of 
motion are produced which I called systematic ; namely, that every 



APPENDIX 679 



change takes place gradually, and every action is accompanied with 
reaction, and new force is not produced without loss of the former, and 
so the one dragging always is retarded by the one dragged, and neither 
more nor less power is contained in the effect than in the cause. 
And since this law is not derived from the notion of mass, it must 
necessarily follow from another thing, which is in bodies, 'namely, 
from the force itself, which certainly always preserves its own quan- 
tity the same, although it is employed by different bodies. Hence 
therefore, besides considerations purely mathematical, and subject to 
the imagination, I have concluded that certain considerations meta- 
physical, and perceptible by the mind alone, must be admitted, and 
a certain principle superior to the material mass, and, so to speak, a 
formal addition, since indeed all the truths of corporeal things can- 
not be concluded from logical and geometrical axioms alone, namely, 
from great and small, whole and part, figure and position, but some 
others must be added from cause and effect, and action and passion, 
by which the reasons of the order of things are saved. Whether we 
call that principle form, or evreAe'xeia, or force, does not matter, pro- 
vided we remember that it is intelligibly exhibited through the 
notion of forces alone. 

But although to-day certain distinguished men, seeing this very 
thing, that the common notion indeed of matter is not sufficient, 
fetch in God arro p,rj^a.vri<i, and take away all force of acting from 
things, a kind of Mosaic philosophy as it were (as Fludd once called 
it), I cannot assent. For although I admit that it has been very 
clearly perceived by them that there is no proper influx of one cre- 
ated substance into another, if the thing is driven to metaphysical 
strictness, and I confess even freely that all things always proceed 
from a continuous creation by God ; yet I think there is no natural 
truth in things, the reason of which is to be sought immediately in 
the divine action or will, but that always in the things themselves 
something has been placed by God, whence all their predicates are 
explained. It is certainly evident that God has created not only 
bodies, but also souls, to which correspond the primitive entelechies. 
But these things will be demonstrated elsewhere by their own proper 
reasons more profoundly drawn out. 

Meanwhile, although I admit an active principle superior to mate- 
rial notions and, so to speak, vital everywhere in bodies, yet T do not 
therefore here agree with Henry More and other men, distinguished 
for piety and genius, who so make use of a certain Archseus 1 or hylar- 
chic principle even for the management of phenomena (ad phenomena 
procuranda), as if forsooth all things cannot be explained mechani- 
cally in nature, and as if those who undertake this seem to make way 

1 Of. New Essays, ante, p. 67, note 3. — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



with incorporeal things, not without suspicion of impiety ; or as if 
with Aristotle it is necessai'y to imagine intelligences in the revolving 
orbs, or the elements must be said to be driven up or down by their 
own form, by a short (compendiosa) but useless method of teaching 
with these, I say, I do not agree, nor has that philosophy pleased me 
any more than that theology of certain ones, who so believed that 
Jupiter thundered or snowed that they even branded the searchers 
after proper causes with the crime of atheism. In my opinion the 
temperament is the best which satisfies both piety and science, so 
that we admit that all corporeal phenomena indeed can be sought 
from efficient mechanical causes, but we know that the mechanical 
laws in the universe are derived from higher reasons, and so we make 
use of a higher efficient cause only in establishing general and remote 
things. But these once established, as often as afterwards we treat 
of the near and special efficient causes of natural things, we give 
no place to souls or entelechies, no more than to the idle faculties 
or inexplicable sympathies, since the primal and most universal 
efficient cause itself, must not intervene unless as far as the ends 
are regarded, which the divine wisdom had in so ordering things, 
that we neglect no occasion of singing his praise and the most beau- 
tiful hymns. 

And in truth final causes (as I have shown by a wholly remarkable 
example of an optical principle, with the strong approval of the very 
celebrated Molyneux in his " Dioptrics ") are repeatedly employed 
with large result even in special physics, not only that we may admire 
the more the most beautiful works of the supreme Author, but also 
that we may sometimes in this way divine what through the way of 
efficient causes not equally or only hypothetically are manifest. Thus 
far perhaps philosophers have not yet sufficiently observed this use. 
And it must be maintained in general, that everything in things can 
be explained in two ways : through the kingdom of power or efficient 
causes, and through the kingdom of wisdom or through final causes; 
God regulating bodies as machines after the manner of an architect 
according to the laws of magnitude or mathematical laws, and indeed 
for the use of souls ; but souls, capable of wisdom, as his own fellow- 
citizens and sharers of a certain society with himself, after the manner 
of a leader, nay of a father rather according to the laws of goodness 
or moral laws for his own glory, both kingdoms everywhere inter- 
penetrating, yet unconfused and undisturbed the laws of each, 
so that at the same time both in the kingdom of power the great- 
est and in the kingdom of wisdom the best is obtained. But we 
propose in this place to establish the general rules of productive 
forces, which we can then use in the explanation of special efficient 
causes. 

Next I came to the true, and indeed precisely the same, estimate 



APPENDIX 681 



of forces, by the most different ways : one indeed a priori, from the 
simplest consideration of space, time, and action (which I elsewhere 
will explain), the other a posteriori, namely, by estimating the force 
by the effect which it produces in consuming itself. For I under- 
stand here not any effect, but that for which force must be expended 
or in which it must be consumed, which you can call, for that reason, 
violent, such as that effect is not, which a heavy body employs in run- 
ning through a perfectly horizontal plane, because in such an effect 
however produced it always retains the same force, although also in 
this very effect rightly treated, so to speak, as harmless, we have followed 
this our method of estimating, but now it is laid aside by us. Further 
I chose that effect of the violent effects which is especially capable of 
homogeneity or division into similar and equal parts, such as exists 
in the ascent of a body possessed of weight : for the elevation of a 
heavy body two or three feet is precisely double or triple the eleva- 
tion of the same heavy body one foot ; and the elevation of a doubly 
heavy body one foot is precisely double the elevation of a single 
heavy body to the height of one foot; whence the elevation of a 
doubly heavy body three feet is precisely six times the elevation of 
a simple heavy body one foot, supposing namely (at least for the 
sake of teaching, although perhaps in truth the matter is otherwise 
constituted, but the error here nevertheless is imperceptible), that 
the heavy bodies gravitate equally in the greater or less distance 
from the horizon. For in an elastic body homogeneity has not with 
equal ease a place. When therefore I wished to compare bodies 
different or endowed with different velocities, I easily saw that, if 
the body A is single and the body B is double, but the velocity of 
each equal, the force of that one is simple, of this double, since, in 
short, whatever is placed in that once is placed in this twice. For in 
B there is a body twice the equal and equivalent of A itself, and 
nothing besides. But if the bodies A and C are equal, but the 
velocity in A is simple and in C double, I saw that, not in short what 
is in A, is doubled in C, since the velocity indeed is doubled, yet not 
also the body. And I saw that here an error has been made by those 
who believed that the force itself is doubled by that reduplication of 
modality (modalitatis) alone ; as already I once observed and sug- 
gested, and that the true and not hitherto (although after so many 
Elements of universal Mathematics have been written) handed-down 
art of estimating consists in this, that finally it attains to something 
homogeneous; that is, a reduplication accurate and of all kinds, not 
only of modes, but also of things. Of which method no other better 
or more remarkable specimen could be given than that which is 
exhibited in this argument itself. 

In order, therefore, to obtain these results, I considered whether 
these very two bodies A and C, equal in magnitude but different in 



LEIBNITZ'S CRITIQUE OF LOCKE 



velocity, could produce some effects equal to their causes and homo- 
geneous among themselves. For thus those things which by them- 
selves could not easily be compared, by their effects at least might be 
compared accurately. I assumed, 

P E moreover, that the effect must be 

| \ | v \ equal to its cause if it is produced 

j \ | >x ^ by the expenditure or consumption 

\ *X =C of the entire force: in which case 

\ ,v it matters not in how much time it 






V\sA i y | is produced. Let us suppose, there- 

_j£y.-r?^l -I fore, the bodies A and C (Fig. 5) 

H c R to be heavy, and to convert their 

FlG 5 force into an ascent, which will hap- 

pen, if at the moment in which they 
have their said velocities, A simple, B double, are known to exist at 
the extremities of the vertical pendulums PA, EC. But it is evident 
from the demonstrations of Galileo and others that, the body A with 
a velocity as 1 at the highest ascending above the horizon HR to 
the height of one foot 2 A H, the body C with a velocity as 2 can surely 
ascend (at the highest) to the height 2 CE of four feet. Whence it 
already follows that a heavy body having a velocity as 2 is in power 
four times as much as the one having a degree of velocity as 1, since by 
the expenditure of all its force it can accomplish, in short, four times 
as much. For raising a pound (that is, itself — id est se ipmm) four 
feet, in short raises four times one pound one foot. And in the 
same manner it is inferred generally that the forces of equal bodies 
are as the squares of the velocities, and thence the forces of bodies 
in general are in reason composed of the simple of the bodies and the 
doubles of the velocities. 

I have confirmed the same things to absurdity (namely, to per- 
petual motion) by bringing back the contrary opinion, generally 
received, especially among the Cartesians, according to which forces 
are believed to be in reason composed of bodies and velocities : which 
method, indeed, I used repeatedly to define a posteriori two states unequal 
in force, and to distinguish the greater at the same time from the less 
by a certain mark. And since in substituting the one for the other, 
perpetual mechanical motion or an effect more powerful than the 
cause does not arise, those states are not in the least equivalent to 
themselves, but that which was substituted for the other was more 
powerful because it has caused something greater to be performed. 
But I assume as certain that nature never substitutes things unequal 
to the forces themselves, but the complete effect is always equal to 
the full cause ; and, in turn, those things which are equal to the 
forces, with safe reckoning can be substituted by us for them with 
the freest supposition, as if we made that substitution in act, and thus 



APPENDIX 



with no fear 1 of perpetual mechanical motion. But if, therefore, it 
were true, as men generally persuade themselves, that a heavy body 
J. as 2 (for so now we assume it) endowed with a velocity as 1, and 
a heavy body C as 1 endowed with a velocity as 2, are equivalent to 
each other, we ought to be able to substitute with impunity the one 
for the other. But this is not true. For let us assume that A as 2 
has acquired a velocity as 1 in the descent 2 A X A from the height 2 AH 
less than a foot; and now in X A itself or in the existing horizon, let 
us substitute instead of it the equivalent (as they wish) weight 
(pondus) C as 1 with a velocity as 2, which ascends as far as to C, or 
to the height of four feet. And so by the descent alone of the weight 
A of two pounds from the height of one foot 2 AH, and having sub- 
stituted its equivalent, we have accomplished the ascent of one pound 
four feet, which is double the former. Therefore we have gained 
just as much force, or we have produced perpetual mechanical mo- 
tion, which is certainly absurd. And it does not matter whether by 
the laws of motions we can actually accomplish this substitution; 
for between equivalents indeed substitution can safely be made. 
Although, indeed, we have thought out various plans by which it 
will be accomplished actually so nearly as we wish, that the entire 
force of the body A will be transferred to the body C, before at rest, 
but which now (A itself being brought to rest) is alone put in motion. 
Whence it will happen, that, instead of a weight of two pounds of a 
velocity as 1, would succeed one pound of a velocity as 2, if these 
were equivalent ; whence we have shown that an absurdity arises. 
For these things are not indeed worthless, nor do they consist in 
logomachies, but are of the greatest use in comparing machines and 
motions. For if any one has force from water or animals or from 
other cause, by which a heavy body of a hundred pounds is kept in 
constant motion, so that within a fourth part of a minute of time 
it can complete a horizontal circle of a diameter of thirty feet ; but 
another maintains that a double weight in its place, in the same 
time, uniformly accomplishes only half the circle with less expendi- 
ture, and reckons that to you as if it were a gain ; be it known that 
you are deceived and caught by half of the forces. But now having 
put to flight errors, let us set forth a little more distinctly in the 
second part of this hastily thrown-off production (Schediasmatis) the 
true and truly to be admired laws of nature. 2 

1 Gerhardt reads, " motii," evidently a typographical error. Dutens, Leibnit. 
op. om., 3, 324, reads, " metu," which the translation follows. — Tk. 

2 Dutens {Leibnit. op. om.., 3, 324) adds: " proponemus, mense Maio exhi- 
benda," i.e. to be presented in the month of May. The article, however, never 
appeared in print, but remained in Ms. among Leibnitz's papers, and was first 
printed by Gerhardt, in his edition of Leibnitz's mathematical writings. A 

of the article is herewith given. — Tk. 



LEIBNITZ'S CRITIQUE OE LOCKE 



ESSAY ON DYNAMICS IN DEFENCE OF THE WONDER- 
FUL LAWS OF NATURE IN RESPECT TO THE FORCES 
OF BODIES, DISCLOSING THEIR MUTUAL ACTIONS 
AND REFERRING THEM TO THEIR CAUSES 1 

[From the Latin] 

Part II . 

The nature of body, nay, of substance in general, not being suffi- 
ciently known, had brought it about (a fact we have already touched 
upon) that certain distinguished philosophers of our time, since they 
placed the notion of body in extension alone, were compelled to have 
recourse to God in order to explain the union between the soul and 
the body, nay, also, the communication of bodies with each other. 
For it must be confessed that it is impossible for a mere extension, 
involving only geometrical notions, to be capable of action and 
passion : and so this alone seemed to be left to them, that, when man 
thinks and undertakes to move his arm, God, as it were, by a primeval 
compact, moves his arm instead of he himself ; and on the other hand, 
when the motion exists in the blood and spirits, 2 God excites percep- 
tion in the mind. But these very things, since they are foreign to a 
correct method of philosophizing, ought to admonish the authors that 
they are resting upon a false principle, and that they have not assigned 
rightly the notion of body, from which such things followed. We 
have shown, therefore, that there is in every substance a force of 
action and, if it is created, of passion also, that the notion of extension 
is in itself not complete, but that a relation to something which is 
extended, whose diffusion or continued replication it makes known, 
and so the substance of a body is presupposed, which involves a power 
of acting and resisting, and everywhere exists as a corporeal mass, 
and the diffusion of this is involved in extension. Whence one day 
we shall kindle a liew light, also, for the explanation of the union of 
the soul and the body. But now we must show how from thence 
follow wonderful and extremely useful practical theorems, pertaining 
to Dynamics, that is, the science which teaches the rules especially of 
corporeal forces. 

It must be known before all things that force, indeed, is some- 
thing truly real, even in created substances ; but space, time, and 
motion have something of a rational entity, and are true and real, 

iGerhardt, Leibniz, math. Schrift., II., 2 [Vol. 6], pp. 246-254; aus d. 
Manuscript, der Konigl. Biblioth. zu Hannover. 

2 Cf. Bacon's theory of the Spiritus, a brief account of which is given by 
Lasswitz, Gesch. d. Atomistik, 1, 431-432. — Tr. 



APPENDIX 685 



not of themselves, but since they involve divine attributes, — im- 
mensity, eternity, operation, or the force of created substances. Hence 
it already follows that there is no vacuum in space or time; that 
motion, moreover, separated from force, or where in it only the geo- 
metrical notions, — magnitude, figure, — and the variation of these 
are considered, is in truth nothing else than a change of position, and 
so motion, as far as (quoad) phenomena are concerned, consists in a mere 
relation, which also Descartes acknowledged, when he defined transla- 
tion from the neighborhood of one body into the neighborhood of 
another. But in deducing his consequences he forgot his definition, 
and determined the rules of motions as if motion was something real 
and absolute. So, therefore, we must consider, if an indefinite num- 
ber of bodies are in motion, that from the phenomena it cannot be 
deduced in which of them absolute determinate motion or rest exists, 
but to any one you please taken from these can be attributed rest, 
provided that the same phenomena come forth. Hence it follows 
(a result which Descartes did not notice) that the uniformity of the 
hypotheses is changed neither by the encounters (concursus) of bodies with 
each other; and besides, that such rules of motions must be assigned 
that the respective nature of motion may remain intact, nor from the 
event after the encounter can it be divined through the phenomena 
where before the encounter there had been rest or determinate abso- 
lute motion. Whence the rule of Descartes does not at all accord 
with the facts, by which he asserts that a body at rest can in no way 
be driven from its place by another smaller body, and other things of 
this sort. Than which nothing is more remote from the truth. It 
follows, also, from the relative nature of motion, that the action of 
bodies against each other by turns or percussion is the same, provided they 
approach each other with the same velocity ; that is, the same appearance 
remaining in the given phenomena, whatever at length be the true 
hypothesis, or to whichever at length we rightly ascribe motion or 
rest, the same event appears in the phenomena sought or resulting, 
even in respect to the action of bodies among themselves. And this 
also is what we find by experience (experimw), that we shall feel the 
same pain, whether our hand runs against a stone at rest, suspended, 
if you please, from a thread, or the stone with the same velocity runs 
against our hand at rest. Meanwhile, we speak thus, according as 
the thing demands, for a more suitable and simpler explanation of 
the phenomena, precisely as in spherics we employ the motion of the 
primum mobile, and in the theory of the planets we must use the 
Copernican hypothesis, so that already these disputes, urged on with 
so much effort (in which even theologians were implicated), straight- 
way disappear. For although force is something real and absolute, 
nevertheless motion pertains to the class of relative phenomena, and 
truth is looked for not so much in phenomena as in causes. 



686 LEIBNITZ'S CRITIQUE OF LOCKE 

From our notions also of body and forces this principle arises, that 
what happens in substance can be known to happen spontaneously and in 
an orderly manner. With this is connected the principle that no 
change takes place by a leap. This posited, it follows also that atoms 
cannot be allowed. That we may seize the 
,A 2 A „B ,B force of this conclusion, let us assume 

I I I IT") r~\ that the bodies A and B (Fig. 6) meet 

A /■ B together and that v i comes to 2 A, and 

' ~ v v'~-^ again X B to 2 B, and thus meeting in 2 A 2 B 

Fig. (3. are reflected from 2 A to S A and from 

2 B to 3 B. But supposing that atoms 
exist, that is, bodies extremely hard and thus inflexible, it is evi- 
dent that the change takes place by a leap or momentary incre- 
ment (momentaneam), for direct motion in the moment (momento) 
itself of the encounter becomes retrograde unless we can assume that 
immediately after the encounter the bodies rest, that is, lose their 
force, which thing, besides the fact that it would otherwise be absurd, 
would continue again the change by a leap, a momentary increment 
(momentaneam) , namely, from motion to 
rest, and not however a transition by 
intermediate steps. And so we must 
know, if the bodies A and B (Fig. 7) 
meet and come from X A X B into the place 
F IGi 7_ of concourse 2 A 2 B, that there they are 

gradually compressed like two inflated 
balls, and more and more approach each other in turn by the con- 
tinually increased pressure ; that, moreover, by this thing the motion 
itself is weakened, the force itself of the effort being carried over 
into the elasticities (elaslra) of the bodies, until at length they are 
reduced to rest ; but then at length the elasticity of the bodies 
restoring them, they themselves rebound from each other in turn 
with a retrograde motion begun again from rest and continually 
increasing ; at length with the same velocity with which they ap- 
proached each other, regained but turned in the opposite direction, 
they recede in turn from each other and return into the positions 
3 A 3 B which coincide with the positions -^A-^B, if the bodies are supposed 
equal and of equal velocity. Thence it is already evident how no 
change takes place by a leap, but the progress being gradually dimin- 
ished and at length reduced to rest, then at length a regress arises. 
So that as from one figure another is not made (as from a circle an 
oval) unless through innumerable intermediate figures, nor is there 
any passing over from a place to a place or from a time to a time 
unless through all intermediate places and times, so not from motion 
is rest produced, and much less an opposite motion, unless through 
all the intermediate degrees of motions. And since this principle 




APPENDIX 687 



is of so great consequence in nature, I wonder it is so little thought 
of. From these considerations follows what Descartes had attacked 
in his letters, and now also certain great men are unwilling to admit, 
that all reflection arises from elasticity, and a reason is given of many 
remarkable experiments which indicate that a body bends before it is 
propelled, as Mariotte has very beautifully illustrated. Finally, that 
especially wonderful principle follows from these considerations, that 
no body is so poor but that it has elasticity, and so is pervaded by 
a fluid still more subtile ; and then that there are no elements of bodies, 
and that neither the most fluid matter nor certain solid globules of 
the second element, exact and durable, are to be granted, but that 
analysis proceeds to infinity. 

It is consistent with this law of continuity, excluding leap from 
change, that a case of rest can be considered as a special case of 
motion, namely, as an evanescent or very small motion, and a case 
of equality can be considered as a case of evanescent inequality. 
Whence the consequence is, that such laws of motions must be 
assigned that there be no need for peculiar rules for bodies equal 
and at rest, but these rules spring from the rules of bodies unequal 
and moving of themselves, or, if we wish to enounce peculiar rules 
for rest and equality, we must be careful lest we assign such as do 
not agree with the hypothesis which considers rest as the last motion 
or equality as the last inequality, otherwise we shall violate the 
harmony of things and our rules will not agree among themselves. 
This new system of testing our own or others' rules, I published first 
in the "Nouvelles de la Republique des Lettres," July, 1687, article 
S, 1 and called it a general principle of order (principimn ordinis gen- 
erate), springing from the notion of the infinite and the continuum, 
adding to it the axiom, that from orderly data the results also are 
orderly (datis ordinatis etiam qucesita sunt ordinata). I expressed the 
principle universally thus : If a case approaches a case continually in 
the data and at length disappears in itself, the results of the cases must 
also approach each other continually in the things sought for, and at length 
cease in turn in themselves. (Si casus ad casum continue accedat in datis 
tandemque in ipsum evanescat, necesse est ut etiam eventus casuum sibi con- 
tinue accedant in quossitis tandemque in se invicem desinant.) Precisely 
as in geometry the case of the ellipse approaches continually the case 
of the parabola, in proportion as one focus remaining another more 
and more remote is regarded as assumed, until in the case of another 
focus infinitely removed the ellipse passes into the parabola. Whence 
all the rules of the ellipse must be verified in the parabola (taken as 
an ellipse whose other focus is infinitely distant). Whence the radii 
falling parallel into a parabola can be conceived as coming from 

1 Cf. Gerhardt, Leibniz, philos. Schrift., 3, 51-55; Erdmann, 104-106. — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



another focus or tending towards it. Since, therefore, in the same 
way a case in which the body A runs against B in motion can be 
varied continually, so that the motion of A itself remaining, the 
motion of B itself is regarded as less and less, until at length it is 
regarded as disappearing in rest and thence again grows in the con- 
trary direction ; I say the result of the attack, but rebounding into 
what whether in A itself or in B itself, continually approaches by 
both motions the result of the attack which exists in the case of B at 
rest, and in it finally ceases ; and thus the case of rest both in the 
data (in datis) and in the result or that which is sought (qucesitis) is 
the limit of the cases of motion in a straight line, or the common 
limit of direct and continuous motion, and thus as it were a special 
example of either. With regard to this touchstone (lydium lapidem), 
brought over by me from geometry to physics, when I examined the 
Cartesian rules of motions, it happened, wonderful to say, that a cer- 
tain hiatus or leap showed itself utterly abhorrent to the nature of 
things, for in expressing quantities by lines, and taking for abscissas 
(pro abscissis) the motions of B itself before the encounter, the data, 
and for ordinates (pro ordinatim applicatis) the motion of the same 
after the encounter, the results sought for, and by drawing the line 
through the extremities of the ordinates (ordinatarum), according to 
the precept of the rules of Descartes, this line was not a continuum, 
but something wonderfully gaping and leaping in a certain absurd 
and unthinkable manner. And when on that occasion I observed also 
that the rules of Rev. Father Malebranche did not bear this examina- 
tion in all things, the distinguished man having considered the matter 
again according to his candor, declared publicly that from this an 
occasion had arisen for him to change his rules, for which reason, 
also, he published a brief pamphlet. Although it must be confessed, 
that because he had not yet directed his attention sufficiently to the 
use of this new system, he has left something now also not yet suffi- 
ciently in all things complete (quadrant). 

From what has been said, this wonderful principle also follows, 
that the passion of every body is spontaneous, or arises from internal force, 
although upon external occasion. I understand here, however, passion 
proper, which arises from percussion, or which remains the same, 
whatever hypothesis at length is assigned, or to whatever at length 
we ascribe absolute rest or motion. For since the percussion is the 
same, to whatever at length true motion corresponds, it follows that 
the result of the percussion is distributed equally between both, and 
thus both act equally in the encounter, and thus half the result ai'ises 
from the action of the one, the other half from the action of the other ; 
and since half, also, of the result or passion is in one, half in the other, 
it is sufficient that we derive the passion which is in one from the 
action also which is in itself, and we need no influence of the one upon 



APPENDIX 



the other, although by the action of one an occasion is furnished the 
other for producing a change in itself. Certainly, while A and B 
meet, the resistance of the bodies, united with their elasticity, causes 
them to be compressed because of the percussion, and the compression 
is equal in each and according to whatever hypothesis, as the experi- 
ments show also, if any one conceives two inflated balls to meet, whether 
both are in motion, or each is at rest, even if the one at rest be sus- 
pended from some thread, in order that it may most easily recede ; 
for, always provided the velocity of approach or the respective velocity 
be the same, the compression, or the intensity of the elasticity, will be 
the same and equal in both. Then the balls A and B, restoring them- 
selves by the force of their own violent, namely, compressed and con- 
fined, elasticity, mutually repel each other by turns, and spread out, 
as it were, in an arc, and, with a force equal on both sides, each is 
driven back by the other, and so, not by the force of the other, but by 
its own force, it recedes from that one. But what is to be understood 
in the case of inflated balls is to be understood in the case of every 
body so far as it is passive in percussion, namely, that the rebounding 
and leaping apart arises from the elasticity in itself, that is, from the 
motion of the permeating etherial fluid matter, and thus from force 
internal, or proceeding from within. I understand, however, as I have 
said, that the proper motion of bodies is separated from the common, 
which can be ascribed to the centre of gravity ; whence their proper 
motion is so to be conceived (to be conceived, I say, by the way of 
hypothesis) as if they were produced on board a ship, which would 
have the motion of their common centre of gravity, but they them- 
selves on board ship were so moved that from the composite common 
motion of the ship or centre, and their own proper motion, the 
phenomena are preserved. From what has been said, also, it is under- 
stood that the action of bodies is never without reaction, and both are equal 
to each other, and' directly contrary. 

Since, then, only force, and thence nascent effort exists in any mo- 
ment (for motion never truly exists, as we have explained above), 
and every effort tends in a straight line, it follows that all motion is 
rectilinear, or composed of rectilinears. Hence, already it not only fol- 
lows that those bodies which move in a curved line, try always to proceed 
in the straight line tangent to it, but also, what any one least expects, 
hence arises the true notion of stability (frmitatis). For, if we suppose 
that some one of those bodies which we call stable (although in truth 
nothing is absolutely stable or fluid, but everything has a certain degree 
of stability or fluidity, by us, however, it is named from a predominant 
regard for our senses) circulates about its own centre, the parts will 
attempt to fly away by the tangent, nay, they will really begin to fly 
away ; but since this separation of themselves from each other in turn, 
disturbs the motion of the encircling body, hence they are repelled, or 
2y 



LEIBNITZ'S CRITIQUE OF LOCKE 



again crowded together towards themselves in turn, as if there were 
in the centre, a magnetic force of attraction, or as if there were in the 
parts themselves a centripetal force, and therefore the revolution will 
arise from the composition of the effort (nisu) to recede from the 
rectilinear by the tangent and the centripetal effort (conatu). And 
thus it remains that all curvilinear motion arises from the composition 
among themselves of rectilinear efforts, and at the same time it is 
understood that this crowding together by the encircling body is the 
cause of all stability. Otherwise it could not be that all curvilinear 
motion was composed of nothing but rectilinear motions. Whence, 
also, again, we have a new and not less than before unexpected argu- 
ment against atoms. Moreover, nothing could be devised more incon- 
sistent with things than that stability be sought from rest, for true 
rest never exists in bodies, nor from rest can anything arise but rest ; 
but although A and B are mutually at rest with themselves, if not in 
fact, at least relatively (although this never occurs exactly, for no body 
preserves exactly the same distance from another, however small the time), 
and although whatever is once at rest will always be at rest unless a 
new cause is added, nevertheless it does not follow, for this reason, 
that because B resists the impelling body, it resists, also, the one 
separating it from another, so that certainly, as the resistance of B 
itself is overcome, or B itself driven forward, at the same time A 
follows. But were the attraction, which is not given in nature, but 
from the primitive stability (Jirmitate), explained through rest or 
something similar, it would assuredly follow. And so stability, also, 
should not be explained unless by the crowding together produced by 
the encircling body. For pressure alone does not sufficiently explain 
the matter, as if the separation of B itself from A itself only is im- 
peded, but it is to be understood that in fact they separate from each 
other in turn, that moreover one is again impelled to the other by the 
encircling body, and thus, from the composition of the two motions, 
this conservation of the conjunction is produced. And so those who 
conceive in bodies certain tablets or insensible layers (for example, of 
two polished marbles, which are exactly applied to each other), whose 
separation is made difficult on account of the resistance of the ambient 
body, and hence explain the stability of two sensible bodies, although 
very often they speak truly, yet when they suppose some stability in 
the layers again, they do not give the last reason for stability. From 
these considerations, also, it can be understood wdiy I cannot in this 
thing continue (stare) in certain philosophic opinions of certain great 
mathematicians, who, besides the fact that they admit vacant space, 
and seem not to shrink back from attraction, consider motion, also, 
as an absolute thing, and hasten to prove it from the revolution and 
the centrifugal force which has thence arisen. But since the revolu- 
tion also arises only from the composition of rectilinear motions, it 



APPENDIX 



follows, if the equivalent of the hypotheses is sound in rectilinear 
motions, however assumed, that it will be sound in the curvilinears. 

From what has been said it can also be understood that the common 
motion in many bodies does not change their actions among themselves, since 
the velocity with which they approach each other in turn, and thus 
the force of the encounter by which they act on each other in turn, 
is not changed. Whence the remarkable experiments follow which 
Gassendi mentions in his letters on motion impressed by a trans- 
ferred motor, that he might satisfy those who seemed to themselves 
to be able to infer the rest of the earth's sphere from the motion 
of projectiles. Nevertheless, it is certain that, if any [persons] are 
borne in a large ship (closed, if agreeable, or certainly so constituted 
that the external phenomena cannot be observed by the travellers), 
and if the ship is moved, although with great velocity, yet quietly or 
uniformly, they themselves will have no principle by which to dis- 
tinguish (from those things, namely, which take place on shipboard) 
whether the ship is at rest or moves, even if by chance they play ball 
on the ship, or practice other movements. And this fact must be 
noted in favor of those whose belief accords with the not rightly 
understood notion of the Copernicans, that according to these, - things 
projected from the earth into the air are carried off (abripi) by the 
air with the gyrating earth, and thus the motion of the bottom fol- 
lows, and fall back upon the earth just as if this were at rest; a view 
which is properly judged insufficient, since the very learned men who 
make use of the Copernican hypothesis conceive, rather, that some- 
thing on the surface of the earth is moved with the earth, and, just 
as if discharged from a bow or hurling machine (tormento) , carries 
with itself the impetus made by the gyration of the earth, together 
with the impetus made by the projection. Thence, when their double 
motion is the one common with the earth, the other peculiar to the 
projection, it is no wander that the common motion changes nothing. 
Meanwhile, it is not to be disguised that, if the projectiles could be 
driven so far, or if the ship were conceived so large, and borne with 
such velocity, that before the descent the heavy earth or ship described 
an arc perceptibly different from a straight line ; a distinction would 
be discovered, because then, indeed, the motion of the earth or ship 
(because circular) does not remain common to the motion which was 
impressed upon the missile by the gyration of the ship or earth 
(because rectilinear). And in the effort of heavy bodies towards the 
centre, external action is added, which can no less produce a diversity 
of phenomena, than if the compass were kept closed on the ship, which 
would certainly indicate a variation of the ship. As often, however, 
as the question concerns the equivalence of hypotheses, all things must 
be united which concur in the phenomena. From these considera- 
tions, also, it is understood that any composition of motions or reso- 



692 LEIBNITZ'S CRITIQUE OE LOCKE 

lution, whatever, of one motion into two or more can safely be 
employed, concerning which, nevertheless, a certain very clever man 
in the works of Wallis had hesitated, not without reason. For the 
matter certainly deserves proof, and cannot (as is done by many) be 
assumed as in itself known. 



VI 
ON THE RADICAL ORIGIN OF THINGS 1 

November 23, 1697 
[From the Latin] 

Besides the world or the aggregate of finite things, there is a 
Unique Being who rules, not only as the mind in me, or rather as I 
in my body rule myself, but also in a much higher manner. For 
this unique sovereign of the universe not only rules the world, but 
also frames or fashions it, and is superior to the world and, so to 
speak, outside the world (extramundanwni) , and thus is the ultimate 
reason of things. For the sufficient reason of existence can be found 
neither in any single thing, nor in the entire aggregate and series 
of things. Let us suppose that there was an eternal book of the 
Elements of Geometry, one copy always made from another, it is 
evident that, although we can account for the present book by the 
past, whence it has been copied, nevertheless we never, by assuming 
in the past as many books as we please, come to the complete reason, 
for we may always wonder why, from all time, such books have 
existed ; that is to say, why these books were written, and why so 
written. What is true of books is likewise true, of the different states 
of the world, for the following state has in a measure been copied 
from the preceding (although according to certain laws of change), 
and so to whatever extent you go back into anterior states, you will 
never find in these states the full reason; that is to say, why any 
world exists rather than none, and why such an one. 

Therefore, although you imagine the world to be eternal, since, 
nevertheless, you assume only a succession of states, and do not find 
in any one of these whatever the sufficient reason, nay more, since by 
assuming any number you please you do not advance even the least 
towards accounting for them, it is evident that the reason must be 
sought elsewhere. For in eternal things we must understand that, 



1 Gerhardt, Leibniz, philos. Schrift., 7, 302-308; Erdmann, 147-150; Janet, 
2, 546-553 (in French). — Tr. 



APPENDIX 



even if there were no cause, yet there is a reason, which in persisting 
things is the necessity itself or the essence ; but in a series of chang- 
ing things, if we suppose that this series proceeds from a prior series 
eternally, the reason would be the prevalence of inclinations, as we 
shall soon see, in which, that is to say, the reasons do not necessitate 
(with an absolute or metaphysical necessity so as to imply the con- 
trary), but incline. From these considerations it is evident that we 
cannot escape the ultimate extramundane reason of things or God 
by assuming the eternity of the world. 

The reasons therefore of the world lie concealed in something 
outside the world, different from the chain of circumstances or series 
of things, whose aggregate constitutes the world. We must then 
come from physical or hypothetical necessity, which determines the 
posterior states of the world from the prior states, to something which 
is of absolute or metaphysical necessity, the reason for which cannot 
be given. For the present world is physically or hypothetically but 
not absolutely or metaphysically necessary. In fact, having assumed 
that it is what it is, it follows that henceforth things must be what 
they are. Since, therefore, the ultimate root must be in something 
which is metaphysically necessary, and since there is no reason of 
the existing unless from the existing, it is therefore necessary that 
a unique being exist of metaphysical necessity, or whose essence is 
existence, and that thus something exists different from the plurality 
of beings or the world, which we have admitted and shown not to 
be of metaphysical necessity. 

But that we may explain a little more distinctly how temporal, 
contingent or physical truths originate in eternal, or essential or 
metaphysical truths, we must first know, that, by the very fact itself 
that something rather than nothing exists, there is some demand 
for existence in possible things or in possibility itself or essence, or 
(so to speak) a stretching forth to existence, and, to sum it up in 
a word, that essence per se tends to existence. Whence it hereafter 
follows, that all possible things, or those expressing essence or pos- 
sible reality, with equal right tend to essence (essentiam 1 ) in pro- 
portion to the quantity of essence or reality, or in proportion to the 
degree of perfection which they involve ; for perfection is nothing 
else than quantity of essence. 

But from this we see most clearly that from the infinite combina- 
tions of possible things and possible series there stands forth one 
through which the greatest quantity of essence or possibility is 
brought through to existence. There is always, in fact, in things a 

1 The reading according to both Gerhardt and Erdmann. Janet's French 
version reads : " l'existence." The argument would seem to require the read- 
ing " existentiam." — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



principle of determination which is to be sought from the maximum 
or minimum, so that beyond question the greatest effect is manifested 
with, so to speak, the least expense. And here time, place, or, in a 
word, the receptivity or capacity of the world can be considered as 
the expense or ground upon which, as conveniently as possible, it 
must be built, while the varieties of the forms correspond to the 
proportion of the building and the number and elegance of the 
rooms. And it is as in certain games when all the places at a table 
must be filled according to certain laws, where, unless you employ 
a certain skill, hindered finally by the unfavorable places, you will 
be compelled to leave vacant more places than you were able or 
desired to do. There is, however, a certain method by which the 
greatest possible space is most easily filled. If therefore, for instance, 
we assume that it has been decreed that there be a triangle, though 
with no other accidentally determining condition, the result is an 
equilateral triangle ; and if it is assumed that we must proceed from 
point to point, though nothing determines the road beyond, the 
easiest and the shortest way will be chosen ; thus having once assumed 
that being prevails over non-being, or that there is a reason why 
something rather than nothing existed, or that from possibility a 
transition must be made to act, it follows hence, in the absence of 
any further determination, that the quantity of existence is as great 
as possible in proportion to the capacity of the time and place (or 
the order of possible existence), just as tiles are so laid that in the 
proposed area as many as possible may be contained. 

From these considerations we understand already in a wonderful 
way how, in the very original formation of things, a certain Divine 
Mathematics or Metaphysical Mechanics is employed, and the deter- 
mination of the greatest amount of existence has place. Thus the 
right angle is the determinate of all the angles in Geometry, and 
liquids placed in different media arrange themselves in the most 
capacious form, namely, the spherical; but especially in general 
Mechanics itself, when many heavy bodies struggle with each other, 
such a motion at length arises, through which the greatest descent 
on the whole is accomplished. For if all possibilities with equal 
right tend to existence according to the measure of reality, so all 
weights by equal right tend to descend in proportion to the measure 
of gravity, and as here the motion appears, in which is contained 
the greatest possible descent of the heavy bodies, so there the world 
appears, through which is realized the greatest possible production 
of possibilities. 

And so also we already have physical necessity from metaphysical : 
for although the world is not metaphysically necessary, so that the 
contrary implies contradiction or logical absurdity, it is nevertheless 
physically necessary or determined so that the contrary implies 



APPENDIX 695 

imperfection or moral absurdity. And as possibility is the source 
of essence, so perfection or the degree of essence (through which 
the greatest number of things are compossible) is the source of exist- 
ence. Whence it is at the same time evident how freedom exists in 
the Author of the world, although he does all things determinately 
because he acts from the principle of wisdom or perfection. Indif- 
ference certainly arises from ignorance, and the greater one's wisdom 
the more he is determined to the most perfect. 

But (you will say) this comparison of a certain determining meta- 
physical mechanism with the physical one of heavy bodies, although 
it seems elegant, nevertheless is wanting in this because the struggling 
heavy bodies truly exist, but the possibilities or essences before or 
besides existence are imaginary or fictitious, therefore no reason of 
existence can be sought in them. I reply that neither these essences 
nor the eternal truths which they call from them are fictitious, but 
exist in a certain so to speak region of ideas, namely in God himself, 
the source of every essence and of the existence of the rest. That 
we do not seem to have spoken gratuitously, the existence itself of 
an actual series of things indicates. For since reason is not found 
in this series, as we showed above, but must be sought in meta- 
physical necessities or eternal truths ; moreover, since existences 
cannot exist unless from existences, as already we maintained above, 
eternal truths must have existence in a certain absolute or meta- 
physically necessary subject, that is in God, through whom these 
things, which otherwise would be imaginary, are (to speak barbar- 
ously but significantly) realized. 

And in truth actually in the world we observe that all things take 
place according to the laws of the eternal verities not only geomet- 
rical but also metaphysical, that is, not only according to material 
necessities, but also according to formal reasons ; and that is true 
not only generally in that reason of the existing rather than non- 
existing, and the so rather than otherwise existing world which we 
have now explained (which certainly is to be sought from the tend- 
ency of possibilities to existence), but also by descending to specials 
we see, by a wonderful plan in all nature, the metaphysical laws of 
cause, power, action, have place, and these prevail over the purely 
geometrical laws themselves of matter, as in giving the reasons of 
the laws of motion I have observed to such an extent that I was 
finally compelled to abandon, as elsewhere I have more at length ex- 
plained, the law of the geometrical composition of impulses (conatuum), 
defended formerly by me, a youth, when I was more materialistic. 

Thus, therefore, we have the ultimate reason of reality both of 
essences and of existences in one, which assuredly greater, above and 
before the world itself is necessarily existent, since through itself 
not only existences, which the world embraces, but also possibilities, 



LEIBNITZ'S CRITIQUE OF LOCKE 



have reality. But this can be sought only in one source on account 
of the connection of all things with each other. It is evident, more- 
over, that from this source existing things continually spring forth 
(promanare) and are produced and the products exist, since it is not 
apparent why one state of the world rather than another, yesterday 
rather than to-day, flows from itself. It is also evident how God acts 
not only physically but also freely, and is in himself not only the 
efficient but also the final cause of things, and how an account is 
taken by him, not only of grandeur and power in the mechanism of 
the universe already constituted, but also of goodness and wisdom 
in that to be constituted. 

And lest any one may think that moral perfection or goodness is 
here confounded with metaphysical perfection or magnitude, and the 
latter being granted may deny the former, it is to be understood that 
it follows from what has been said, not only that the world is the 
most perfect physically, or, if you prefer, metaphysically, or that 
that series of things has been produced in which the greatest pos- 
sible reality is actually manifest, but also that it is the most perfect 
morally, because in reality moral perfection in souls themselves is 
physical. Whence the world is not only an especially admirable 
mechanism, but also, as far as it is composed of souls, is the best 
Republic, through which there is brought to souls the greatest pos- 
sible felicity or joy in which their physical perfection consists. 

But, you will say, we experience the contrary in the world, for the 
best very often fare the worst, the innocent, not only beasts, but also 
men, are struck down, and even killed with torture ; finally, the world, 
especially if the government of the human race be regarded, seems 
rather a certain confused chaos than a thing arranged by a certain 
supreme wisdom. So at first view I confess it seems, but the contrary 
must be established by a more thorough inspection ; a priori, it is 
evident from these very considerations which have been brought for- 
ward, that the highest possible perfection, namely, of all things, and 
so also of mind, is obtained. 

And in truth it is unjust to judge, unless after an investigation of 
the whole law, as the jurisconsults say. We know a small part of the 
eternity extending into immensity ; for how little is the memory of a 
few thousands of years which history recounts for us. And yet, from 
so small experience we judge rashly concerning the immense and the 
eternal, as men in a prison, or, if you prefer, born and educated in 
the subterranean salt-pits of the Sarmatians, thought that there is no 
other light in the world but that dim lamp light scarcely sufficient 
to direct their steps. We look at a very beautiful picture, we cover 
this entirely, reserving a small portion ; what else in this will appear, 
even if you look very attentively, nay, how much more will you observe 
from near by than a certain confused congeries of colors without 



APPENDIX 697 

choice, without art; and nevertheless, when the whole covering is 
removed, and you shall see the whole picture in the proper position, 
you will know that that which seemed thoughtlessly spread upon the 
canvas has been done with the highest art by the author of the work. 
What the eyes observe in pictures, the ears perceive in music. Eminent 
composers very often mix discords with concords in order to arouse, 
and, as it were, sting the hearer, and as more solicitous concerning 
the outcome, all having soon been restored to order, that he may 
rejoice so much the more, in short, that we may take pleasure in 
petty dangers or experiences of evils by the sense itself, or by the 
display of either our power or happiness ; or, as we delight in the 
spectacle of the rope-dancers, or in the sword-dance (saltatione inter 
gladios — sauts perilleux, Leibnitz), things that themselves excite terror, 
and we, our very selves, half let down the children in sport, as it 
were, now almost about to throw them before us, just as the ape 
bore Christian, king of Denmark, when an infant, and wrapped in 
swaddling clothes, to the roof of the house, and while all were anxious, 
like one in sport boi*e him safe back again into his cradle. In accord 
with the same principle, it is insipid always to eat sweet things ; 
sharp, sour, nay more, bitter things which excite the taste, are to be 
mixed with them. He who has not tasted the bitter, has not deserved, 
nay more, will not appreciate the sweet. This itself is the law of joy, 
that pleasure does not proceed uninterruptedly ; for this produces 
disgust, and makes us inert, not joyful. 

But what we have said of this part which can be disturbed while 
the harmony on the whole is preserved is not so to be interpreted as 
if no account is taken of the parts, or as if it would suffice that the 
whole world be complete in its own parts, although it can happen 
that the human race is wretched, and that there is no care for justice 
in the universe, or account taken of us, as some think, who judge not 
rightly enough concerning the totality of things. For we must know 
that, as in the best constituted republic, care is taken that it be as 
well as possible with individuals, so the universe would not be suffi- 
ciently perfect unless, while the harmony of the universe is preserved, 
as much regard is had for particular interests. Of which thing no 
better measure could be constituted than the law itself of justice, 
saying that each should take part in the perfection of the universe, 
and in happiness proper in proportion to the measure of his own 
virtue and of that will which is a disposition of mind (affectus) toward 1 
the common good, by which that itself is completed which we call the 
affection and love of God, in which alone the force and also the power 
of the Christian religion consists, in the judgment even of the wise 
theologians. Nor should it seem wonderful that so much is conferred 

1 Gerhardt reads, incorrectly," ergo" ; Erdmann, correctly, " erga" — Tb. 



LEIBNITZ'S CRITIQUE OF LOCKE 



upon souls in the universe, since they very closely reproduce the image l 
of the supreme author, and are related to him not only as machines to 
the maker (like the rest), but also as citizens to the prince, and will 
continue in existence equally with the universe itself, and express and 
concentrate in a measure the whole in themselves, so that it can be 
said that souls are the entire parts. 

But as regards the sufferings especially of good men, it must cer- 
tainly be maintained that they result in their greater good, and that 
is true not only theologically, but also physically, as the grain cast 
into the earth suffers before it bears fruit. And on the whole, it can 
be said that sufferings, temporarily evil, are in effect good, since they 
are the short roads to greater perfection. So, in physics, those liquors 
which ferment slowly are improved more slowly, but those in which 
the fermentation is stronger are improved more readily, the parts 
being thrown off with greater force. And this is, as you would say, 
to go back, in order, by a greater effort, to leap forwards (qu'on recule 
pour mieux sauter, — you go back to take a better leap) . These views, 
therefore, must be maintained to be not only pleasing and comforting, 
but also most true. And in general, I think there is nothing, both 
truer than happiness, and more propitious and more delightful than 
truth. 

Respecting the increase also of the beauty and general perfection 
of the divine works, a certain perpetual and very free progress of the 
whole universe is to be recognized, so that it proceeds to ever greater 
culture. As for instance, a great part of our earth receives culture 
and will receive more and more. And although it is true that some- 
times some parts grow wild again or are destroyed and depreciated, 
yet this must so be understood, as a little before we interpreted suf- 
fering, namely, that this destruction and depreciation itself is useful 
in the attainment of something greater, so that in some measure we 
gain by the very loss. 

And as to the objection which might be made that thus the world 
should long ago have been made a paradise, the reply is at hand: 
although already many substances have attained great perfection, 
nevertheless, on account of the divisibility of the continuum to infinity, 
there always remain in the abyss of things parts hitherto asleep, to be 
aroused and carried forwards to something greater and better, and, in 
a word, to a better culture. And accordingly, progress never comes 
to an end. 

1 Both Gerhardt and Erdmarm read, " imagine " ; manifestly a typographi- 
cal error for " imaginem." — Tr. 



APPENDIX 



VII 
APPENDIX 1 

May, 1702 
[From the Latin] 

Up to the present time, I have published no book, indeed, against 
the Cartesian philosophy, but often in the " Acta Eruditorum Lipsien- 
sium " and the " Journaux " of France and Holland hastily-thrown-off 
productions (Schedkmnata) will be found inserted by me, in which I 
have borne witness to my dissent from it. But first (not to speak 
now of the others), about the nature of the body and what motive 
forces are in the body; in all others my opinion was the same. The 
Cartesians, it is true, place the essence of body in extension alone, but 
I, although with Aristotle and Descartes against Democritus and Gas- 
sendi I admit no vacuum, and against Aristotle with Democritus and 
Descartes think there is nothing but an apparent rarefaction and con- 
densation, yet I think with Democritus and Aristotle against Des- 
cartes, that there is something passive in body besides extension, that, 
namely, by which body resists penetration ; but besides this, I also 
recognize with Plato and Aristotle against Democritus and Descartes 
an active force or evreAe'xeta, so that I think Aristotle so far rightly 
defined nature as the source (principium) of motion and rest, not 
because I think any body, unless already in motion, can be moved by 
itself or be put in motion by any quality such as gravity, but because 
I think every body always has implanted in it motive force (motricem), 
nay, rather motion actually intrinsic (inotum intrinscum actualem), from 
the very beginning of things. Moreover, I agree with Democritus and 
Descartes against the multitude of the Scholastics, that the exercise of 
the motive (motricis) power and the phenomena of bodies can always 
be explained mechanically, the causes themselves of the laws of motion 
being withdrawn which spring from a higher source, namely, from the 
entelechy, which cannot be derived from the passive mass alone and 
its modifications. 

But in order that my opinion may be better understood and its 
reasons also may be somewhat apparent, I think, in the first place, 
that the nature of body does not consist in extension alone, because 
in evolving the notion of extension we must notice that it is relative 
to something that is extended and signifies a diffusion or repetition 

1 Gerhardt, Leibniz, math. Schrift., II, 2 [Vol. 6], 98-106 ; Gerhardt, Leibniz, 
philos. Schrift., 4, 393-400; cf. G.'s Einleitung, ibid., 271-272. The letter to 
Honoratus Fabri, and this Appendix, were printed by Gerhardt from the Ms. 
in the Royal Library at Hanover. 



700 LEIBNITZ'S CRITIQUE OF LOCKE 

of a certain nature. For every repetition (or multitude of the same 
things) is either discrete, as in numbers where aggregate parts are 
discerned; or is continuous, where the parts are indeterminate and 
can be assumed in infinite ways. Continua, however, are of two kinds ; 
the one successive, as time and motion, the other simultaneous or 
consisting of coexisting parts, as space and body. And as in time 
we conceive nothing else than the disposition or series itself of varia- 
tions, which can occur in itself, so in space we perceive nothing 
else than the possible disposition of bodies. And so when space is 
said to be extended, we accept the statement in the same sense as 
when time is said to endure or number to be numbered; for, in 
truth, time adds nothing to duration nor space to extension, but as 
successive variations are in time, in body those things are diverse 
which can be diffused. For, because extension is a simultaneous 
continuous repetition as duration is a successive one, as often as the 
same nature is diffused at the same time through many things, as 
ductility or specific gravity or the yellow-color in gold or the white- 
color in milk, extension is said to have place generally in body as 
resistance or impenetrability, although it must be confessed that that 
diffusion continuous in color, weight, ductility, and things similar in 
kind but homogeneous, is only apparent and has no place in parts 
however small, and so the extension of resistance alone which is 
diffused through matter preserves this name with the strict investi- 
gator. But it is evident from these considerations, that extension is 
not an absolute predicate, but relative to that which is extended or 
diffused, and from the nature of which, diffusion can just as little be 
separated as number from the thing numbered. And hence those 
who assumed extension as an absolute primitive attribute, indefinable 
and apprjTov, erred by defect of analysis and took refuge in the 
occult qualities which for the rest they so despised, as if extension 
were something that cannot be explained. 

The question now is asked, What is that nature whose diffusion 
constitutes body? We have already said that matter is constituted 
by the diffusion of resistance ; but since in our opinion there is some- 
thing else in body besides matter, the question is asked in what its 
nature consists. We say, therefore, it can consist in nothing else 
than iv ra Swa/jUKiS or the indwelling principle of change and pei'- 
sistence. Whence also it uses the physical doctrine of the two mathe- 
matical sciences to whose principles it was subordinated, geometry 
and dynamics, the elements of which latter science not yet sufficiently 
propounded, I have elsewhere promised. Moreover, geometry itself, 
or the science of extension, again is subordinated to arithmetic, be- 
cause in extension, as I said above, there is repetition or multitude, 
and dynamics is subordinated to metaphysic which treats of cause 
and effect. 



APPENDIX 701 



Again, to Svvol/aikov or power in body is twofold, — passive and active. 
Passive power properly constitutes matter or mass, active evreAe^eta 
or form. Passive power is the resistance itself by which body resists 
not only penetration but also motion, and by which it happens that 
another body cannot enter into its place unless itself yields, but 
itself does not yield unless by retarding somewhat the motion of the 
impelling body, and so it attempts to continue steadfastly in its 
former state, not merely that it may not depart thence voluntarily, 
but also that it may resist change. And so there are therein two 
resistances or masses : the first antitypy, as they call it, or impenetra- 
bility ; the second resistance, or what Kepler calls the natural inertia 
of bodies, which Descartes also somewhere in his letters acknowledged, 
from the fact that bodies certainly receive no new motion unless by 
force, and so resist the impression and break its force. This would 
not happen if there were not in the body, besides extension, to Svva- 
/AiKov or the principle of the laws of motion, by which it happens that 
the quantity of forces cannot be increased, nor can a body even be 
impelled by another unless its own force is broken. This passive force 
in the body, moreover, is everywhere the same and proportional to 
its magnitude. For although some bodies appear more dense than 
others, this nevertheless happens because their pores are more filled 
with matter pertaining to the body, while, on the contrary, the rarer 
bodies have the nature of a sponge, so that another more subtile 
matter glides through their pores which is not reckoned with the 
body nor its motion followed or looked for. 

Active force, which also absolutely is customarily called force, is 
not to be conceived as a simple common power of the schools, or as a 
receptivity of action, but involves a conatus or tendency to action, so 
that, unless something else hinders, action follows. And in this 
properly consists evreXe^eta, too little understood by the schools ; for 
such a power involves act (actum), and does not persist in a naked 
faculty, although it does not always proceed wholly to the action 
(actionem) to which it tends, as often, namely, as an impediment is 
thrown in its way. Again active force is twofold, — primitive and deri- 
vative ; that is, either substantial or accidental. Primitive active force, 
which is called by Aristotle evreAe^eta f) irpwrq, generally the form of 
substance (forma substantias), is another natural principle which with 
material or passive power completes the corporeal substance, which is, 
forsooth, a unum per se, not a mere aggregate of many substances; for 
there is much difference, for example, between an animal and a flock. 
And so this entelechy or soul, or something analogous to the soul, 
exists, and always naturally actuates some organic body, which itself 
separately assumed (quod ipsum separatim sumtum), when the soul is 
separated forsooth or removed, is not one substance, but an aggregate 
of many ; in a word, a natural machine. 



702 LEIBNITZ'S CRITIQUE OF LOCKE 

This natural machine, moreover, has this highest prerogative as 
compared with an artificial, that exhibiting a proof of a divine author, 
it consists of infinite organs wrapped up in itself, and so can never be 
utterly destroyed, just as it cannot be absolutely produced, but can 
be diminished only and increased, and be involved and evolved, this 
being to a certain extent itself a substance, and in it (however trans- 
formed) a certain degree of vitality, or, if you prefer, of primitive 
activity being always preserved. For what is said of animate things 
must also be said proportionally of those which are not properly ani- 
mals. Meanwhile, it must be maintained that intelligences, or the 
more noble souls which are also called spirits, are ruled by God not 
only as machines, but also as subjects, and are not liable to those 
changes to which other living beings are exposed. 

Derivative force is that which some call impetus, a conatus evidently 
or tendency, so to speak, to a certain determinate motion, by which 
accordingly primitive force or the principle of action is modified. I 
have shown that this is not preserved the same in the same body, but 
yet, however distributed in many, it remains the same in the amount 
and differs from motion itself, whose quantity is not preserved. And 
this itself also is the impression which a body receives by impulse, by 
whose aid projectiles continue their motion and do not need any new 
impulse, which Gassendi also has illustrated by elegant experiments 
made on shipboard. Thus also some incorrectly think that projectiles 
have their motion continued by the air. Further, derivative force 
differs from action only as the instantaneous from the successive; for 
there is already force in the first instant, but action requires a period 
of time, and so is brought to pass by the prolongation of forces in 
time, which is perceived in any part of the body whatever. And so 
action is in reason composed of body, time, and force (vis) or energy 
(virtutis), since by the Cartesians the quantity of motion is estimated 
by the calculation of velocity in the body, and forces are considered 
far otherwise than as velocities, as will soon be stated. 

To place active force in bodies moreover, many things compel us, 
and especially the experience itself, which shows that motions are in 
matter, although these motions must be attributed originally to the 
general cause of things, — God; immediately, however, and specifically, 
they must be attributed to the force placed in things by God. For to 
say that God in creation has given to bodies a law of action, is nothing 
unless he has given at the same time something by which the law is 
observed ; otherwise he himself will be obliged always to procure in 
an extraordinary manner the observance of the law. Yea, rather his 
law is efficacious, and makes bodies efficient ; i.e. he gave to them 
natural (insitarri) force. Further, we must consider that derived force 
and action is a certain mode (modale), since it admits change. But 
every mode is constituted by some modification of something persist- 



APPENDIX 703 



ing or more absolute. And just as figure is a certain limitation or 
modification of passive force or extended mass, so derivative foi'ce and 
moving action (actio matrix) is a certain modification not certainly of 
a thing merely passive (otherwise a modification or limit would involve 
more reality than the thing itself which is limited), but of something 
active, that is, of the primitive entelechy. Therefore, derivative and 
accidental or changeable force will be a certain modification of the 
primitive energy (virtutis) essential to and abiding in every corporeal 
substance. Whence the Cartesians, since they acknowledge no active 
principle substantial and capable of modification in the body, are 
compelled themselves to reject (abjudicare) all action, and to trans- 
fer it to God alone, a far-fetched mechanical view (accersitum ex 
Machina), which is not philosophical. 

But primitive force is changed by derivative in the impacts of 
bodies, according as the exercise of primitive force is turned within 
or without. For in truth, every body has an internal motion, nor can 
it ever be brought to rest. This internal force, again, turns itself with- 
out, when it perforins the duty of elastic force, when, namely, internal 
motion is impeded in its accustomed course, whence every body is 
essentially elastic, water not even excepted, and how violently this 
rebounds, even the cannon balls (pilce tormentariaz) show. And 
unless every body were elastic, the laws of motions could not be 
proved true and binding. Meanwhile this force does not always 
render itself conspicuous in the sensible parts themselves of bodies, 
since these manifestly do not sufficiently cohere. But the harder a 
body is, the more elastic it is and the more strongly it rebounds. 
Indeed in impact, when bodies mutually rebound from each other, 
this occurs through elastic force, whence indeed bodies always have 
their own special motion from impact by their own special force, to 
which a foreign impulse furnishes only an occasion of acting, and, so 
to speak, a determination. 

Hence, moreover, we understand that, although that primitive 
force or form of substance (which, it is true, determines even the 
forms in matter, while it produces motion) is admitted, yet in ex- 
plaining elastic force and other phenomena we must always proceed 
mechanically, certainly by the forms which are modifications of 
matter and by impulses which are modifications of form. And it is 
useless, when distinct and specific reasons should be given, to have 
recourse immediately and in general (generice) to form or primitive 
force in a thing, as it is useless in explaining the phenomena of created 
things to recur to the first substance or God, unless his means or ends 
are at the same time specifically explained, and the proximate efficient 
or even the special final causes are rightly assigned, so that his power 
and wisdom appear. For in general (whatever Descartes may have 
said), not only efficient, but also final causes, belong to physical dis- 



704 LEIBNITZ'S CRITIQUE OF LOCKE 

cussion (tractationis) ; precisely as a house is badly exhibited, if any of 
its parts betrays its structure only, not its use. I have further already 
pointed out above that, since we affirm that all things in nature are 
explained mechanically, the reasons themselves of the laws of motion 
or the principles of mechanics must be excepted, which should be 
deduced not from mathematics alone and the imagination of the sub- 
ject, but from a metaphysical source, namely, from the equality of 
cause and effect, and from other laws of this kind which are essential 
to entelechies. Certainly, as has already been said, physics is subor- 
dinate through geometry to arithmetic, through dynamics to meta- 
physics. 

But the Cartesians, not sufficiently understanding the nature of 
forces, confounding motive force with motion, have seriously erred 
in determining the laws of motions. For although Descartes knew 
that the same force must be preserved in nature, and that a body, 
although he attributed a part of its force (namely, the derivative) 
to another, so retains a part that the sum of the forces remains the 
same, (yet), deceived by the example of equilibrium or dead force 
as I call it (which here does not enter into the reckoning, and of 
living force or of that which is now in question, it is only an infini- 
tesimal part), (he) believed that force exists in a composite system 
(ratione composita) of masses and velocities, or that it is the same as 
that which he calls quantity of motion, by which term he under- 
stands the product of the mass into the velocity (ex ductu massce in 
celeritatem), when, nevertheless, it has elsewhere been demonstrated 
by me a priori that forces exist in a composite system of simple 
masses and double velocities. I know that lately certain learned 
men, when at length they were compelled to admit against the 
Cartesians that the same quantity of motion is not preserved in 
nature, and considered this too alone as absolute force, concluded 
that this force also does not abide, and took refuge in the conserva- 
tion alone of relative (respective) force, but we have discovered that 
not in the conservation of absolute force even has nature been 
mindful of her own constancy and perfection. And the opinion 
of the Cartesians indeed, in which the quantity of motion is pre- 
served, contradicts all the phenomena, (while) ours is wonderfully 
confirmed by experiments. 

The Cartesians err, also, in this, because they think that changes 
occur by a leap (per saltum) ; as if, for example, a body at rest can in 
a moment pass over into a state of determined motion, or as if a body 
placed in motion can suddenly be brought back to rest, not by passing 
through the intermediate grades of velocity, because they have plainly 
not understood the use of elastic force in the concourse of bodies. 
Which, if it were absent, I confess that neither the law which I call 
the law of continuity would be observed in things, through which 



APPENDIX 705 



leaps are avoided, nor the law of equivalence by which absolute forces 
are conserved, nor other excellent inventions of nature's architect 
have place, by which the necessity of matter and the beauty of form 
are united. Moreover, the elastic force itself implanted in every body 
shows that there is in every body, also, internal motion and infinite 
(so to speak) primitive force, although in the impact itself, when 
circumstances demand, it is determined by derivative force. [For, as 
in an arch, any part whatever sustains the entire weight, or in a tense 
cord the traction, and any portion whatever of compressed air, has as 
much force as the weight of the ah- pressing upon it, so any corpuscle 
whatever, of the entire ambient (arribientis) mass is solicited to action 
by the conspiring force, and awaits nothing but an occasion for exer- 
cising its power, as is shown by the example of gunpowder (pulveris 
pyrii)~\. 

There are many other things in which I have been obliged to de- 
part from Descartes, but those which I have now brought forth relate 
chiefly to the principles themselves of corporeal substances, and, if you 
interpret them rightly, are capable of vindicating the ancient philos- 
ophy of a healthier school, which I see deserted by many of the 
more recent scholars, even those well disposed towards it, where there 
was no need. The philosophy of Ptev. Father Ptolemseus, 1 a man 
very versed in the principles of the ancients and the moderns, whose 
remarkable teaching I examined myself, at Rome (from which philos- 
ophy I promise myself very much), has not yet reached us. 

In a note, Leibnitz has added : In addition, I am pleased to state, 
that although very many Cartesians boldly reject forms and forces in 
bodies, Descartes nevertheless spoke more moderately, and professed 
this only, that he found no reason for using them. I indeed admit 
■ that they should be rejected if of no use ; but in this very thing I 
have shown that Descartes has erred. For not only in entelechies, or 
tc5 Swa/nKa>, are placed the principles of mechanism, by which all 
things are regulated in bodies, but I have also shown in the " Acta 
Eruditorum," 2 when I was replying to the very celebrated man, John 
Christopher Sturm, 3 who attacked, in his " Physica Eclectica," my in- 

1 Giovanni Battista Tolomei, 1653-1726, was acquainted with all the Euro- 
pean languages and had a very extensive knowledge of all the sciences of his 
time, and was reputed a profound theologian and skilful critic. Among his 
works was Philosophia mentis et sensuum, Romse, 1696, fol., Augustse Vin- 
delicorum, 1698, fol. — Tn. 

2 Sept. 1698. The piece is the De ipsa natura, cf. Gerhardt, Leibniz, philos. 
Schrift., 4, 504-516 ; Erdmann, 154-160 ; Jacques (in French) , 1, 455-468 ; Janet 
(in French), 2, 553-567 ; transl., Duncan, 112-126. Of. also Gerhardt's Einlei- 
tung, op. cit., 4, 417. — Tr. 

3 Johann Christoph Sturm, 1635-1703, was, from 1669, Professor of Mathe- 
matics and Physics at the University of Altdorf. His Physica Eclectica 
appeared at Nuremhurg, 1697, 4to. While not celebrated for physical dis- 

2z 



706 LEIBNITZ'S CRITIQUE OF LOCKE 

sufficiently understood doctrine, with irrefragable demonstration that, 
completeness being assumed, if there were nothing in matter but mass 
itself and arrangement of its parts, it would be impossible for any 
perceptible variation whatever to occur, since equivalences are substi- 
tuted for limits, and by banishing conatus, or the force of tendency, 
to the future (the entelechies, that is, being removed), the state of 
things present at one moment cannot be distinguished from the state 
at any other moment. And I think Aristotle perceived this when he 
saw that, besides local motion, change is necessary in order to satisfy 
the phenomena. But changes, although in appearance manifold, just 
as qualities, are reduced in the last analysis to variation alone of forces. 
For all the qualities of bodies, that is, all their real stable accidents, 
except forms (that is, those which do not exist in transition, as motion, 
but are known as present, although referred to the future), are at 
length, when analysis is set up, reduced to forces. Further, when 
forces are removed, nothing real remains in motion itself, for from 
variation alone of arrangement it cannot be determined where the 
true motion or the cause of variation is. 



VIII 

LETTER OF LEIBNITZ TO BASNAGE DE BEAUVAL, 
EDITOR OF THE "HISTOIRE DES OUVRAGES DES 
SAVANTS," PRINTED IN THAT JOURNAL, JULY, 1698, 
pp. 329 sq* 

Explanation of the difficulties which M. Bayle has found in the New 
System of the Union of the Soul and the Body 

[From the French] 

I take the liberty, Sir, to send you this explanation of the diffi- 
culties which M. Bayle has found in the hypothesis which I have 
proposed in order to explain the union of the soul and the body. 
Nothing is kinder than the manner which he has used towards me, 
and I consider myself honored by the objections he has placed in 
his excellent Dictionary, in the article Rorarius. Moreover, a mind 
as great and as profound as his cannot make them without instruct- 
ing, and I shall try to profit by the light which he has shed upon 

coveries, he emphasized the method of experiment, and spread abroad a taste 
for experimenting. Germany is said to owe to him the introduction of the 
teaching of mathematics into the gymnasia and the common schools. — Tr. 

1 Cf. Gerhardt, Leibniz, philos. Schrift., 4, 517-524, cf. Q.'sEinleitung, ibid., 
419; Erdmann, Leibnit. op. philos., 150-154; Jacques, (Euvres de Leibniz, 1, 
481-487; Dutens, Leibnit. op. om., 2, Pt. I., 74-79. 



APPENDIX 707 

these matters in this part as well as in many other parts of his work. 
He does not reject what I had said of the conservation of the soul 
and also of the animal, but he does not yet appear satisfied with the 
manner in which I have claimed to explain the union and the inter- 
course of the soul and the body in the " Journal des Savants " of June 
27 and of July 4, 1695, and in the " Histoire des ouvrages des savants," 
February, 1696, pp. 274, 275. 

Here are his words, which seem to indicate wherein he has found 
difficulty: "I cannot understand," he says, "the series of actions, 
internal and spontaneous, which would cause the soul of a dog to 
feel pain immediately after having felt joy, although it were alone in 
the universe." I reply that when I said that the soul, although only 
God and it should exist in the world, would feel all that it now 
feels, I only employed a fiction in supposing that which cannot happen 
naturally, in order to show that the feelings of the soul are only a 
consequence of that which is already in it. I know not whether the 
proof of incomprehensibility which M. Bayle finds in this series must 
be sought alone in that which he calls lower, or whether he wished 
to introduce it from this time by the example of the spontaneous pas- 
sage from joy to pain ; perhaps, by wishing to throw out a hint that 
this passage is contrary to the axiom which teaches us that a thing 
always continues in the state in which it is once if nothing occurs 
which obliges it to change, and that thus the animal having once joy 
will always have it if it is alone or if nothing external makes it pass 
to pain ; in every case I agree with the axiom, and, further, I main- 
tain that it is in my favoi', as in fact it is one of my grounds. Is it 
not true that from this axiom we conclude, not only that a body at 
rest will always be at rest, but also that a body which is in motion 
will always preserve this motion or change, that is to say, the same 
volocity and the same direction, if nothing occurs to hinder it? Thus 
a thing does not remain only so long as it depends upon itself (d'elle) 
in the state in which it is ; but also when this is a state of change, 
it continues to change, following always one and the same law. Now 
it is, according to my view, the nature of created substance to change 
continually according to a certain order which conducts it spontane- 
ously (if I may avail myself of this word) through all the states 
which will happen to it, so that he who sees all, sees in its present 
state all its past and future states. And this law of order, which con- 
stitutes the individuality of each particular substance, has an exact 
relation to that wmich happens in every substance and in the entire 
universe. Perhaps I do not make too bold a statement if I say that 
I can demonstrate all this, but at present the question is only of 
maintaining it as a possible hypothesis suitable for explaining the 
phenomena. Now in this way the law of the change of the substance 
of the animal bears it from joy to pain at the moment that a continu- 



LEIBNITZ'S CRITIQUE OF LOCKE 



ous solution is made in its body, because the law of the indivisible 
substance of this animal is to represent what is done in its body in 
the way that we experience it, and also to represent in some fashion 
and in relation to this body all that is done in the world ; the unities 
of substance being nothing else than different concentrations of the 
universe represented according to the different points of view which 
distinguish them. 

M. Bayle continues : " I understand why a dog passes immediately 
from pleasure to pain when, being very hungry, and eating bread, 
we give him a blow with a stick." I do not know whether we 
understand it sufficiently. No one knows better than M. Bayle him- 
self, that it is in this that the great difficulty consists of explaining 
why that which passes in the body produces a change in the soul, and 
that it is this which has forced the defenders of occasional causes to 
recur to the care which God must take to represent continually to the 
soul the changes which take place in the body ; whilst I believe that 
it is the nature itself which God has given it to represent in virtue of 
its own laws what passes in the organs. He continues : 

" But that his soul is constructed in such a way that at the moment 
he is struck he would feel the pain, although we should not strike 
him, although he should continue to eat the bread undisturbed and 
unhindered, this is what I cannot understand." I do not remember, 
also, to have said it, and we could say it only by a metaphysical fiction, 
as when we suppose that God annihilates a body in order to produce 
a vacuum, both being equally contrary to the order of things. For 
since the nature of the soul was made at first in a manner suited to 
represent successively the changes of matter, the case we suppose 
cannot happen in the natural order. God could give to each substance 
its phenomena independent of those of others ; but in this way he 
would have made, so to speak, as many worlds without connection as 
there are substances ; almost, as we say, that when we dream we are 
in a world apart, and that we enter into the common world when we 
awake. It is not that the dreams are unrelated to the organs and the 
rest of the body, but that they are related in a manner less distinct. 
Let us continue with M. Bayle : 

" I find, also," says he, " the spontaneity of this soul very incompati- 
ble with the feelings of pain, and, in general, with all the perceptions 
which are displeasing to it." This incomprehensibility would be cer- 
tain, if spontaneous and voluntary were the same thing. Everything 
voluntary is spontaneous; but there are spontaneous actions which 
are without choice, and consequently are not voluntary. It does not 
depend upon the soul, always, to procure feelings which please it, 
since the feelings it will have depend upon those which it has had. 
M. Bayle proceeds : 

" Moreover, the reason why this clever man does not apjirove the 



APPENDIX 



Cartesian system appears to me to be a false supposition : for it cannot 
be said that the system of occasional causes makes the action of God 
intervene by a miracle (Deum ex machina) in the reciprocal dependence 
of the body and soul; for, as God intervenes only according to general 
laws, he does not act there in an extraordinary way." It is not for 
this reason alone that I do not approve of the Cartesian system ; and 
if you consider mine a little, you see clearly that I find in itself that 
which leads me to embrace it. Moreover, if the hypothesis of occa- 
sional causes should not need miracle, it seems that mine Avould not 
cease to have other advantages. I have said that we may imagine 
three systems to explain the intercourse we find between the soul and 
the body ; namely, first, the system of the influence of the one upon 
the other, which is that of the schools taken in the common sense, 
which I believe impossible, after the Cartesians; second, that of a 
perpetual overseer, who represents in the one that which takes place 
in the other, very much as if a man were charged with making two 
bad clocks always to agree, which of themselves would not be capable 
of agreeing, and this is the system of occasional causes ; and third, 
that of the natural agreement of two substances such as would exist 
between two very accurate clocks : and I find this as possible as the 
system of the overseer, and more worthy of the author of these sub- 
stances, clocks or automata. But let us see whether the system of 
occasional causes does not in reality suppose a perpetual miracle. 
They say here, no, because God would act according to this system 
only through general laws. I agree, but, in my opinion, that is not 
sufficient in order to remove the miracles : if God did it continually, 
they would not cease to be miracles, taking this word not popularly, 
as a thing rare and wonderful, but philosophically, as that which 
exceeds the forces of created beings. It is not sufficient to say that 
God has made a general law; for, besides the decree, there must also 
be a natural means of executing it ; that is to say, what takes place 
must be capable of being explained by the nature which God gives to 
things. The laws of nature are not so arbitrary or so indifferent as 
many think. If God decreed, for example, that all bodies should 
have a tendency toward a circular line, and that the radii of the circles 
should be proportional to the size of the bodies, it would be necessary 
to say that there is a means of executing this decree by more simple 
laws, or rather, it would be necessary to admit that God will execute 
it miraculously, or at least by angels expressly charged with this care, 
very nearly like those who were sometimes given to the celestial 
spheres. It would be the same if some one said that God has given 
to the bodies natural and primitive gravities by which each should 
tend to the centre of its globe, without being pushed by other bodies ; 
for in my opinion this system would need a perpetual miracle, or at 
least the assistance of the angels. 



710 LEIBNITZ'S CRITIQUE OF LOCKE 

" Does the internal and active property communicated to the forms 
of bodies know the series of actions it is to produce ? Not at all ; for 
we know by experience that we are ignorant that we have in an hour 
such or such perceptions." I reply that this property, or rather this 
soul or form, does not know them distinctly, but that it feels them 
confusedly. There is in each substance traces of all which has hap- 
pened to it and of all which will happen to it. But this infinite mul- 
titude of perceptions hinders us in distinguishing them ; as when I 
hear a great confused noise of a whole people, I do not distinguish 
one voice from another. 

"It would be necessary, then, that the forms be directed by some 
external principle in the production of their acts ; would not this be 
the Deus ex machina, just the same as in the system of occasional 
causes ? " The preceding reply puts a stop to this inference. On the 
contrary, the present state of each substance is a natural result of its 
preceding state ; but there is only one infinite intelligence therein 
which can see this result, for it envelops the universe in souls as well 
as in each portion of matter. 

M. Bayle concludes with these words : " Finally, as he supposes 
with much reason that all souls are simple and indivisible, we cannot 
understand how they can be compared to a pendulum, that is to say, 
that by their original constitution they can diversify their operations, 
by availing themselves of the spontaneous activity which they would 
receive from their Creator. We conceive clearly that a simple being 
will always act uniformly, if no foreign cause turns it aside. If it 
were composed of many pieces, as a machine, it would act diversely, 
because the particular activity of each piece might change at every 
moment the course of that of the others ; but in a single substance, 
where will you find the cause of the change of operation ? " I find 
that this objection is worthy of M. Bayle, and that it belongs to those 
which most deserve to be cleared up. But I also think that if I had 
not provided for it at. first, my system would not deserve to be ex- 
amined. I have compared the soul to a pendulum only in regard to 
the regulated precision of its changes, which is indeed but imperfect 
in the best clocks, but which is perfect in the works of God ; and we 
may say that the soul is an immaterial automaton of the most accurate 
kind. When it is said that a simple being will always act uniformly, 
there is a distinction to be made, if to act uniformly is to follow per- 
petually one and the same law of order or of continuity, as in a cer- 
tain rank or series of numbers, I admit that every simple being itself, 
and indeed every complex being acts uniformly; but if uniformly 
means likewise, I do not agree. To explain the difference of this 
sense by an example, a movement in a parabolic line is uniform in 
the first sense ; but it is not so in the second, the portions of the para- 
bolic line not being similar among themselves like those of the straight 



APPENDIX 711 



lines. It is true, to mention it in passing, that a simple body left to 
itself describes only straight lines, if we speak only of the centre 
which represents the motion of this entire body ; but when a simple 
and rigid body, having once received a turbination or circulation 
around its centre, retains it in the same sense and with the same velo- 
city, it follows that a body left to itself may describe circular lines by 
its points distant from the centre, when the centre is at rest, and even 
certain quadratrices, when this centre is in motion, which have the 
ordinate composed of the straight line running through the centre, 
and of the right sine whose versed sine is the abscissa, the area being 
to the circumference as this straight line is to a given straight line. 
We must consider also that the soul, wholly simple as it is, has always 
a feeling composed of many perceptions at once, which fact effects 
as much for our purpose as if it were composed of pieces like a 
machine. For each preceding perception influences the following, 
conformably to a law of order which exists in perceptions as in move- 
ments. Thus the majority of philosophers, for many centuries, who 
allow thoughts to souls and to angels, which they believe destitute of 
all body, to say nothing of the intelligences of Aristotle, admit a 
spontaneous change in a simple being. I add that since the percep- 
tions which are found together in one and the same soul, at the same 
time, involve a multitude veritably infinite of minute indistinguishable 
feelings as the sequel must develop, we must not be astonished at the 
infinite variety of that which must result therefrom in time. All this 
is only a consequence of the representative nature of the soul, which 
must express what passes and indeed what will pass in its body, and 
in some fashion in all others, through the connection or correspon- 
dence of all parts of the world. It would perhajjs suffice to say that 
God, having made atoms corporeal, might also well have made them 
immaterial to represent the first ; but we have thought it would be 
well to dwell upon it a little more. 

For the rest, I have read with pleasure what M. Bayle says in the 
article Zeno. It might, perhaps, be perceived that what can be drawn 
therefrom agrees better with my system than with every other, for 
what there is of reality in extension and motion consists only in the 
ground of the order and the regulated series of phenomena and per- 
ceptions. In like manner, as many academicians and sceptics as 
those who wish to reply to them, seem to be embarrassed principally 
only because they sought a greater reality in sensible things outside 
of us than that of the regulated phenomena. We conceive extension 
in conceiving an order in coexistences, but we must not conceive 
it any more than space, after the fashion of a substance. It is like 
time, which presents to the mind only an order in changes. And as 
for motion, what is real therein is the force or the power ; that is to 
say, what there is in the present state which carries with itself a 



LEIBNITZ'S CRITIQUE OF LOCKE 



change for the future. The rest is only phenomena and relations. 
The consideration of this system shows also that, when we enter into 
the heart of things, we find more reason than we thought in the 
majority of the philosophic sects. The little substantial reality of 
the sensible things of the Sceptics ; the reduction of all to harmonies 
or numbers, ideas, and perceptions of the Pythagoreans and Platon- 
ists ; the one and also the all of Parmenides and of Plotinus without 
any Spinozism ; the Stoic connection, compatible with the spontaneity 
of the others ; the vital philosophy of the Kabbalists and Hermetics 
who put feeling above everything; the forms and entelechies of 
Aristotle and the Scholastics, and even the mechanical explanation 
of all particular phenomena, according to Democritus and the moderns, 
and so forth, find themselves reunited as in a centre of perspective, 
whence the object, obscured in regarding it from an entirely different 
point, shows its regularity and the agreement of its parts ; we have 
failed through a sectarian spirit in limiting ourselves by the rejection 
of others. The formalist philosophers blame the material or cor- 
puseulary ones, and vice versa. We wrongly give limits to the division 
and subtilty as well as to the richness and beauty of nature when we 
posit atoms and the vacuum, when we imagine certain primary ele- 
ments, such as the Cartesians, instead of veritable unities, and when 
we do not recognize the infinite in everything, and the exact expres- 
sion of the greatest in the smallest, united to the tendency of each 
to develop itself in a perfect order, which is the most admirable and 
the most beautiful result of the sovereign principle, whose wisdom 
would leave nothing better to be desired by those who could under- 
stand its economy. 



IX 

FRAGMENT OF A LETTER TO AN UNKNOWN 
PERSON 

October 16, 1707 1 

[From the French] 

I think, then, I have good reasons for believing that all the differ- 
ent classes of beings whose union forms the universe, exist in the 
ideas of God only as so many ordinates of the same curve, the union 
of which does not allow the placing of others between them, because 
that would indicate disorder and imperfection. Men are connected 

1 Guhrauer, Leibnitz, Eine Biographic, Anmerkungen z. zw. Buche, pp. 
31-33. Guhrauer says in the note which contains the Fragment here translated : 
"The Principle of Continuity, with which Leibnitz accomplishes so much in 



APPENDIX 713 



with the animals, these with the plants, and these again with the 
fossils, which will be united in their turn with bodies which the 
senses and the imagination represent to us as perfectly dead and 
shapeless. Now since the law of continuity demands that when the 
essential determinations of a being approach those of another so that like- 
wise accordingly all the properties ' of the first must gradually approach 
those of the last, it is necessary that all the orders of natural beings 
form only one chain, in which the different classes, like so many 
links, connect so closely the one to the other, that it is impossible 
for the senses and the imagination to fix the precise point where any 
one begins or ends : all the species which border on or which occupy, 
so to speak, the regions of inflection and retrogression being obliged 
to be equivocal and endowed with characters which can refer to the 
neighboring species equally. Thus the existence of Zoophytes for 
example, or, as Buddeus 1 calls them, Plant-Animals, 'is nowise mon- 
strous, but it is indeed agreeable to the order of Nature that there 
are some. And such is the force of the principle of continuity with 
me that, not only should I not be astonished to learn that beings had 
been found which as regards many properties, for example, those of 
maintaining and multiplying themselves, might pass for vegetables 
with as good right as for animals, and which would reverse the ordi- 
nary rules, based upon the supposition of a perfect and absolute sepa- 
ration of the different orders of simultaneous beings which fill the 
universe; I should be so little astonished, I say, that I am indeed 
convinced that there must be such, that Natural History will perhaps 
some day succeed in knowing them, when it shall have studied more 
this infinite number of living beings, whose minuteness hides them 
from ordinary observation and which are found concealed in the 

Psychology, led him to surprising glimpses in his views of animate nature. 
Nowhere has Leibnitz expressed himself so clearly upon this subject, as in the 
letter to an unknown person, of Oct. 16, 1707, of which a fragment occasioned 
the notorious controversy between Maupertuis and Konig, 1752. It stands 
with many others in Konig's Appel au Public du jugement de Vacademie 
roy 'ale de Berlin, etc. See p. 45. [Then follows the letter] . . . . This is the 
same letter which the Berlin Academy, under the inspiration of Maupertuis, 
declared a forgery, and struck off the list of the Academicians Professor 
Konig as an impostor. — There are perhaps few pieces of Leibnitz, whose 
genuineness are so certified to the connoisseur, as this letter (which Dutens 
and Erdmann have overlooked) . Voltaire also (in his letter to Konig) recog- 
nized its genuineness at once, although only from motives which he drew from 
the style. The Academy was right only in the fact that the letter could not 
have been addressed to Hermann. Of. Leibn. opp. [ed. Dutens] , 3, 531." — Tn. 
1 Leibnitz probably refers to Johann Franz Buddeus, 1667-1729, assistant 
in the philosophical faculty at Wittenberg, Professor of Greek and Latin at . 
Coburg Gymnasium, of Philosophy at Halle, and of Theology at Jena. He 
published Elementa philosophise practices instrumentalis et theoretics^, Hake, 
1703.— Tr. 



714 LEIBNITZ'S CRITIQUE OF LOCKE 

bowels of the earth and the depths of the waters. We remarked 
only since yesterday what grounds have we for denying to reason 
what we have not yet had occasion to see? The principle of con- 
tinuity is then beyond doubt with me, and might aid in establishing 
many important truths in the true philosophy, which, raising itself 
above the senses and the imagination, seeks the origin of phenomena 
in the regions of the intellect. I natter myself that I have some ideas 
concerning them, but this age is not qualified to receive them. 



THAT THE MOST PEBFECT BEING EXISTS 1 
[From the Latin] 

I call every simple quality which is positive and absolute, or 
expresses whatever it expresses without any limits, a perfection. 

But a quality of this sort, because it is simple, is therefore irresolv- 
able or indefinable, for otherwise, either it will not be a simple 
quality but an aggregate of many, or, if it is one, it will be circum- 
scribed by limits and so be known through negations of further 
progress 2 contrary to the hypothesis, for a purely positive quality was 
assumed. 

From these considerations it is not difficult to show that all perfec- 
tions are compatible with each other or can exist in the same subject. 

For let the proposition be of this kind: 

A and B are incompatible 
(for understanding by A and B two simple forms of this kind or 
perfections, and it is the same if more are assumed like them 3 ), it is 
evident that it cannot be demonstrated without the resolution of 
the terms A and B, of each or both; for otherwise their nature 
would not enter into the ratiocination and the incompatibility could 
be demonstrated as well from any others as from themselves. But 
now (by hypothesis) they are irresolvable. Therefore this proposi- 
tion cannot be demonstrated from these forms. 

But it might certainly be demonstrated by these if it were true, 
because 4 it is not true per se, for all propositions necessarily true are 

1 Gerhardt, Leibniz, philos. Schrift., 7, 261-262. Of. Gerhardt's Einleitung, 
ibid., 251. ~ Tr. 

2 Leibnitz had first written : " atque ita ope negationum," i.e. and thus also 
hy means of negations. — Gerhardt. — Tr. 

3 The words, " idemque est . . .," were added later. — Gerhardt. — Tr. 

4 For the following, up to the words: " aut per se notae," Leibnitz at first 
wrote: "(esset enirn necessaria, neque tamen per se nota)" i.e. for it would 
be necessary, and yet not known per se. — Gerhardt. — Tr. 



APPENDIX 715 



either demonstrable or known per se. Therefore, this proposition is 
not necessarily true. Or 1 if it is not necessary that A and B exist in 
the same subject, they cannot therefore exist in the same subject, and 
since the reasoning is the same as regards any other assumed qualities 
of this kind, therefore all perfections are compatible. 

It is granted, therefore, that either a subject of all perfections or 
the most perfect being can be known. 

Whence it is evident that it also exists, since existence is contained 
in the number of the perfections.' 2 

Gerhardt says : " In the foregoing is found what Leibnitz brought 
before Spinoza. The following he appears later to have added : " 

[The same can be shown also as regards the forms composed from 
the absolute forms, provided they are granted.] 

I showed this reasoning to D. Spinoza when I was in The Hague, 3 
who thought it solid; for when at first he opposed it, I put it in writ- 
ing and read this paper before him. 

Schol. 

The reasoning of Descartes concerning the existence of the most 
perfect being assumed that the most perfect being can be known, or 
is possible. For this being assumed because a notion of this kind is 
granted, it immediately follows that that being exists, since we framed 
the notion in such a way that it immediately contains existence. But 
the question is asked whether it is within our power to conceive such 
a being, or whether such a notion exists on the side of the thing, and 
can be clearly and distinctly known without contradiction. For the 
opponents will say that such a notion of the most perfect being or of 
a being existing through his essence is a chimera. Nor is it sufficient 
for Descartes to appeal to experience and to allege that he perceives 
the same in such a manner in himself clearly and distinctly, for this 
is to break off, not to complete the demonstration, unless he shows 
• the method through which others also can attain the same experience ; 
for as often as we bring experiences into the midst of the demonstra- 
tion, we ought to show others also the method of producing the same 
experience, unless we wish to convince them by our authority alone. 

1 This sentence up to "omnes perfectiones," was added later. — Gerhardt. 
— Tr, 

2 At first : " inter perfectiones." — Gerhardt. — Tr. 

3 November, 1676 ; cf. Guhrauer, Leibnitz, Eine Biographie, Pt. I., 184. — Tr. 



716 LEIBNITZ'S CRITIQUE OF LOCKE 



XI 
WHAT IS IDEA 1 

[From the Latin] 

First of all (however), by the term Idea we mean something which 
is in our mind; marks (vestigia) therefore impressed upon the brain 
are not ideas, for I assume as certain that the mind is something else 
than the brain, or a more subtile part of the brain substance. 

But there are many things in our mind — for example, thoughts, 
perceptions, affections — which we know well are not ideas, although 
without ideas they would not be produced. For idea for us consists 
not in a certain act of thought, but in a poiver (facultate), and we say 
we have an idea of a thing, although we do not think of it, provided 
we can on a given occasion think of it. 

There is nevertheless also in this a certain difficulty, for we have a 
remote power of thinking about all things, even of those of which we 
have not perchance ideas, because we have the power of recovering 
them ; idea, therefore, demands a certain power near at hand of thinking 
about a thing or facility. 

But not even this suffices, for he who has a method which if he 
follows he can attain the thing, does not, therefore, have an idea of it. 
As, if I should enumerate in order the sections of a cone, it is certain 
that I would come into the knowledge of opposite hypei-bolas, although 
I have not yet an idea of them. There must necessarily, therefore, 
be something in me, which not only leads to the thing, but also expresses it. 

That is said to express anything in which are contained conditions 
corresponding to the conditions of the thing to be expressed. But 
these expressions are varied ; for example, the model of the machine 
expresses the machine itself, a perspective drawing of a thing in a 
plane expresses a solid, an oration expresses thoughts and truths, 
letters express numbers, an algebraic equation expresses a circle or 
other figure ; and because these expressions have something common, 
from the contemplation of the conditions of the expressing thing, we 
can come into the knowledge of the corresponding properties of the 
thing to be expressed. Whence it is evident that it is not necessary 
that that which expresses be similar to the thing expressed, provided 
a certain analogy of conditions is preserved. 

It is also evident that some expressions have a basis in nature", but 
others at least are partly based in will (arbitrio), as are the expressions 
which are produced by sounds or characters. Those things which 

1 Gerhardt, Leibniz, philos. Schrift., 7, 263-264. Of. Gerkardt's Einleitimg, 
ibid., 251-252. — Tr. 



APPENDIX 



are based upon nature demand either some similitude, such as exists 
between a great circle and a little one, or between a region and a map 
of the region ; or at least a connection such as exists between a circle 
and an ellipse which represents it in perspective (optice), for any point 
whatever of an ellipse corresponds, according to a certain fixed law, 
to some point of a circle. Nay, rather, the circle, by any other similar 
figure in such a case, would be badly represented. In like manner, 
every complete effect represents a complete cause ; for I can always, 
from the knowledge of such effect, come to the knowledge of its cause. 
Thus the deeds of each one represent his mind, and the world itself 
in a measure represents God. It can also happen that those things 
which arise from the same cause express themselves by turns ; for 
example, gesture and discourse. So certain deaf persons understand 
those who speak, not by the sound, but by the motion of the mouth. 

And so the idea of things existing in us is nothing else than the 
fact that God, the author alike of things and the mind, has impressed 
this power of thought upon the mind, so that out of its own workings 
it can draw those things which perfectly correspond to those which 
follow from things. And so, although the idea of a circle is not like 
the circle, yet from it truths can be drawn which in the true circle 
experience would no doubt confirm. 



XII 

ON THE METHOD OP DISTINGUISHING REAL 
FROM IMAGINARY PHENOMENA 1 

[From the Latin] 

Being is that the concept of which involves something positive, or 
that which can by us be conceived, provided that which we conceive 
is possible, and does not involve a contradiction, which we know, 
both if the concept is perfectly explained, and involves no confusion ; 
and briefly, if the thing actually exists, for that which exists is cer- 
tainly a being or a possible thing. 

But as far as Being is explained by a distinct concept, so is Existence 
by a distinct perception ; and that we may the better understand this, 
we must see in what ways existence is proved. And in the first place, 
without proof, I affirm existence, from the simple perception or ex- 
perience of which I am conscious within myself ; that is, in the first 
place, myself, thinking the various things, then the various phenomena 

1 Gerhardt, Leibniz, philos. Schrift., 7, 319-322; Erdmann, Leibnit. opera 
philos., 443^45. — Tr. 



LEIBNITZ'S CRITIQUE OF LOCKE 



themselves, or the appearances which exist in my mind. For these 
two, since they are immediately perceived by the mind with the inter- 
vention of no other, can be wholly proved, and it is equally certain 
that there exists in my mind the species of a mountain of gold or of a 
centaur, when I dream of these, as it is certain that I exist who dream ; 
for each is contained in this one thing, that it is certain that the 
centaur appears to me. 

Let us now see by what signs we may know what phenomena are real. 
"We determine this now, both from the phenomenon itself, and from 
the antecedent and consequent phenomena. From the phenomenon 
itself, whether it be vivid, multiplex, congruous. It will be vivid, if 
the qualities, as light, color, heat, appear sufficiently intense; it will 
be multiplex if they are varied, and adapted to many tests and to the 
institution of new observations ; for example, if we experience in the 
phenomenon not only colors but also sounds, odors, flavors, tactile 
qualities, and those things both in the whole and in its various parts, 
which again we can discuss in various relations (yariis causis trac- 
tate). Which things, indeed, a long series of observations, instituted 
especially with design and with choice, is wont to meet neither in 
dreams nor in those images which the memory or the phantasy pre- 
sents, in which the image is very often weak and also disappears 
(disparei) in the course of the discussion. The phenomenon will be 
congruous when it consists of many phenomena, the reason of which 
can be given from themselves in turn, or from some common hypothesis 
sufficiently simple ; then it will be congruous if it preserves the usage 
of other phenomena which have frequently presented themselves to us 
so that the parts of the phenomenon have that position, order, result, 
which similar phenomena have had. Otherwise, they will be suspected ; 
for if we should see men moved in the air, sitting upon the hippogryphs 
of Ariosto, we should doubt, I think, whether we were dreaming or 
awake. But this proof can be referred to another head of con- 
siderations assumed from the preceding phenomena. With which 
phenomena the present phenomenon must be congruous, if, namely, 
they preserve the same usage, that is, if the reason of this can be 
given from the preceding, or all agree with the same hypothesis as a 
common reason. But, undoubtedly, the strongest proof is the agree- 
ment with the whole course of life, especially if very many others 
affirm that the same agrees with their own phenomena also ; for, that 
other substances similar to us exist, is not only probable, but indeed, 
certain, as I shall soon say. But the most powerful proof of the reality 
of phenomena, which, indeed, alone suffices, is the success in predicting 
future phenomena from the past and present, whether that prediction 
is founded in reason, or in the hypothesis thus far succeeding, or in 
the usage thus far observed. Nay, although this entire life were said 
to be nothing but a dream, and the visible world nothing but a 



APPENDIX 719 



phantasm, I should call this dream or phantasm real enough, if, using 
reason well, we were never deceived by it ; but just as we know from 
these what phenomena must be regarded as real, so, on the other 
hand, whatever phenomena conflict with these which we judge real, 
also those whose fallacy we can explain from their own causes, these 
only we think apparent. 

But it must be confessed that the proofs of real phenomena which 
thus far have been brought forward, howsoever united, are not demon- 
strative ; for, although they hare the greatest probability, or, as is 
commonly said, produce a moral certainty, they, nevertheless, do not 
create a metaphysical certainty, so that the assertion of the contrary 
implies a contradiction. And thus, by no argument can it be abso- 
lutely demonstrated that there are bodies, nor anything keep certain 
well-ordered dreams from being objects to our mind, which are 
considered by us as true, and on account of the agreement among 
themselves with respect to use are equivalent to truths. Nor is the 
argument of great weight, as they commonly allege, that thus God 
would be a deceiver ; certainly, every one sees how far this is from 
a demonstration of metaphysical certainty, for we are deceived by our 
own judgment, not by God, when we assert anything without accu- 
rate proof. And although there is present great probability, never- 
theless God is not therefore a deceiver who presents this to us. For 
what, if our nature were not perchance capable of real phenomena ; 
surely God would be not so much to be blamed as to be thanked, for, 
by causing these phenomena, since they could not be real, to be at 
least accordant, he showed us that which in the entire usage of life 
would equal in worth real phenomena ; what, indeed, if this whole 
short life were nothing but a certain long dream, and we should awake 
only in death ? a conception such as the Platonists seemed to have ; 
for since we are destined for eternity, and this whole life, although it 
should continue many thousands of years, has in respect of eternity 
the value of a point, how small will be the interposition of such a little 
dream in the full truth, the ratio of which is much less than that of 
the dream to life; and yet no sane person will say that God is a 
deceiver, if by chance he should happen to observe any short but 
distinct and congruous dream in his mind. 

Hitherto I have spoken of those things which appear; now we 
must see about those which do not appear, which, nevertheless, can 
be inferred from those which do appear. And indeed it is certain 
that every phenomenon has some cause. JSTow if any one says that the 
cause of the phenomena is in the nature of our mind, in which the 
phenomena are, he will affirm nothing indeed false, but nevertheless 
he will not express the whole truth. For, in the first place, there is 
necessarily a reason why we ourselves exist rather than not exist, and 
although we should assume that we existed from eternity, yet the 



720 LEIBNITZ'S CRITIQUE OF LOCKE 

reason of the eternal existence must be sought, which reason must 
be found either in the essence of our mind or outside it. And, 
indeed, there is nothing to prevent the existence of innumerable other 
minds as well as ours ; but all possible minds do not exist, which I 
prove from this, because all existing things have intercourse with 
each other. Further, minds can be known of another nature than 
ours and having intercourse with this of ours. Moreover, that all 
existing things have intercourse with each other is demonstrated both 
from this, that otherwise we cannot say whether anything in respect 
to these things happens now or not, and so the truth or falsity of 
such a proposition is not given, which is absurd, and because many 
extrinsic denominations are given ; nor does any one become a 
widower in India by the death of his wife in Europe, without a real 
change happening in him. For every predicate is truly contained in 
the nature of the subject. If now some possible minds exist, we ask 
why not all ; then because it is necessary that all existing things have 
intercourse, it is necessary that there be a cause of this intercourse, 
nay, it is necessary that all express the same nature, but in a different 
way ; but the Cause through which it happens, that all minds have 
intercourse or express the same thing and so exist, is that which per- 
fectly expresses the universe, namely God. The same cause has no 
cause and is unique. Hence it is at once evident that many minds 
exist besides ours, and since it is easy to think that men who are con- 
versant with us can have just as much reason to doubt concerning us 
as we concerning them, and no greater reason wages war in our 
behalf, they also exist and will have minds. Hence already, sacred 
and profane history, and whatever things pertain to the state of minds 
or rational substances, are considered as confirmed. 

With respect to bodies, I can demonstrate that not only light, heat, 
color, and similar qualities are apparent, but also motion and figure 
and extension. And if anything is real, that alone is the power of 
acting and enduring, and so in this (as it were matter and form), 
consists the substance of the body ; but those bodies which have no 
substantial form, those only are phenomena, or at least aggregates of 
the true. 

Substances have metaphysical matter or passive power as far as 
they express anything confusedly, active, as far as they express it 
distinctly. 



ADDITIONS AND CORRECTIONS 



The following Additions and Corrections are made in the interest of the 
greater accuracy and completeness of the book. The material incorporated 
therein has been obtained chiefly since the earlier portion of the book was in 
type. As it could not be introduced in its proper place, it is deemed best to 
insert it here rather than to omit it altogether. It will be noticed that it per- 
tains chiefly to the earlier portion of the New Essays, the annotation of 
which, not a part of the Translator's plan at the outset, began with the print- 
ing and has grown with the progress of the work. — Tk. 

Page 3, note 2, add : Erdmann, 677-678. The letter, after speaking 
of the nature, processes, and extent of our knowledge of physics, proceeds 
thus : ' ' You enquire concerning the things of spirits or rather concern- 
ing incorporeal things ; and you say that we see the mechanical disposi- 
tion of the parts, but that we do not see the principles of the mechanism. 
Very well, but when we see motion also, then we know the cause of the 
motion or force. The source of the mechanism is primitive force (vis 
jmmitiva), hut the laws of motion, according to which impulses (impetus) 
or derivative forces arise out of this primitive force, proceed from the 
perception of good and evil, or from that which is most fitting. Thus 
it happens that efficient causes depend upon final causes, and spiritual 
things are by nature prior to material things, as indeed to us they are 
prior in knowledge, because we perceive more immediately (interim) the 
mind (nearest — intimam — to us) than the body, as indeed Plato and 
Descartes have observed. This force, you say, is known by its effects, 
not as it is in itself. I reply that so it would be if we had no. mind, and 
did not know. The mind has in itself perceptions and appetites, and in 
these its nature consists. And as in the body we know avrirvirlav, and 
form in general, although we do not know what the forms of the insensible 
bodies are, so in the mind we know perception and appetite, although we 
do not know distinctly the. insensible ingredients of the confused percep- 
tions, by which the insensible things of bodies are expressed. Spiritual 
things are perceived, you say, just as the air, the wind, the light, yet not 
on that account sufficiently known ; but to me the air, the wind, the light 
seem to be no more spiritual than running water, nor do they differ from 
this save in subtility. Spirits, minds, and simple substances or monads in 
the universe cannot be comprehended by the senses and the imagination, 
because lacking in parts. Do you ask whether I believe that there are 
bodies which do not fall within the range of vision ? Why may I not 
3 a 721 



LEIBNITZ'S CRITIQUE OF LOCKE 



believe ? nay, rather, concerning them I think I cannot doubt. In micro- 
scopes we see animalcula otherwise imperceptible, and the nerves of these 
animalcula and other animalcula by chance swimming in their own fluids 
cannot be seen. The subtility of nature proceeds into infinity. Finally 
you seek for definitions of matter, body, spirit. Matter is that which con- 
sists in antitypia, or that which resists penetration, and so naked matter 
is merely passive. Body, moreover, has besides matter also active force. 
Body, moreover, is either a corporeal substance or a mass collected from 
corporeal substances. Corporeal substance I call that which consists in a 
simple substance or monad (i.e. in the mind or somewhat analogous to 
the mind) and in an organic body united to it. But mass is an aggregate 
of corporeal substances, as a cheese sometimes consists of a conflux of 
worms. Then a monad or a substance simple in kind contains perception 
and appetite, and is either primitive or God, in which is the ultimate 
reason of things, or derivative, that is a created monad, and this is either 
endowed with reason, Mind (mens), or endowed with sense, that is 
Soul (anima), or endowed with a certain lower grade of perception 
and appetite, or analogous with soul (animce analoga), which is content 
with the naked name of monad, since we do not know its various grades. 
Every monad, furthermore, is inextinguishable ; for simple substances 
can neither begin nor end, except by creation or annihilation, that is, 
miraculously. And, moreover, every created monad is endowed with a 
certain organic body, by means of which it perceives and appetizes, 
although it is variously (e)volved through births and deaths, involved, 
transformed, and exists in a perpetual flux. Monads, then, contain in 
themselves the Entelechy, or the primitive force (vis primitiva), and 
without them matter would be passive merely ; and any mass whatever 
contains innumerable monads, for although each organic body of nature 
has its own corresponding monads, yet it contains in the parts other 
monads endowed in like manner with their own organic bodies serving 
the primary body ; and all nature is nothing else, for all aggregates must 
necessarily result from simple substances, as it were from true elements. 
But atoms or extended bodies, and yet infrangible, are a fiction, which 
cannot be explained except by a miracle, and are without reason ; nor 
may we from them assign the causes of the forces and motions. And 
although they might be admitted, they would not be truly simple, for this 
very reason, because they are extended and endowed with parts. Thus I 
have replied to your questions, and set forth my views, as far as may be 
in a few words and by letter." 

Page 9, line 15. For " 1709," read " 1704," and cf. infra, p. 101, note 
1, line 3 from bottom, and infra, p. 531, note 2, TIT 2, 3, where this por- 
tion of note 1, p. 101, is corrected. 

Page 13, note 1. Add : translation also in Duncan, Philos. Whs. of 
Leibnitz, 94-99 ; German translation in J. H. v. Kirchmann, Die klein. 
philos. wichtig. Schrift. v. Leibniz, 86-92 (Philos. Bibliothelc, Bd. 81; 
Erlduterungen, Bd. 82), Leipzig, 1879. 



ADDITIONS AND CORRECTIONS. 723 

Page 15, note 2. After "translation," instead of "Appendix," etc., 
read " Duncan, Philos. Wks. of Leibnitz, pp. 71-80 ; German translation 
in J. H. v. Kirchmann, Die klein, philos. wichtig. Schrift. v. Leibniz, 
55-67." 

Page 16, line 22, " Huygens." Cf. infra, p. 150, note 3. On Huygens' 
physical views, cf. Lasswitz, Gesch. d. Atomistik, 2, 341-397. New ed. 
Huygens, (Euvres completes, La Haye, 1888-1893, 5 vols., still in prog- 
ress. These 5 volumes contain correspondence only. 

Page 16, line 30, "pliable." "Leibnitz means," says J. H. v. Kirch- 
mann, Erlixuterungen zu Leibniz, d. klein. philos. wichtig. Schrift., Leipzig, 
1879, p. 109, " that, although bodies contain no vacuum, yet from the fact 
that they can become greater or lesser in extent, the other substances 
which fill out the gaps of the body proper are by pressure removed from 
it, or conversely with the cessation of the pressure penetrate into its 
vacuum. An actual extension or cohesion of a definite homogeneous body, 
which contains no gaps, Leibnitz does not assume, although the Scholastics 
affirmed it for a long time." On the development of Leibnitz's views 
from the atomism to which he was at first inclined, but almost immedi- 
ately rejected, to the dynamic idealism of his monad doctrine, cf. D. 
Selver, Der Entwicklungsgang d. Leibniz. Monadenlehre bis 1695, Leip- 
zig, William Englemann, 1885; Lasswitz, Gesch. d. Atomistik, 2, 446 sq. 

Page 17, line 11, " De Seriebus infinitis." Cf. infra, p. 424, note 2. 

Page 21, line 12, "Eabritius." Cf. infra, p. 102, note 2. The letter 
of Fabritius to Spinoza here mentioned is found in Spinoza, Opera, ed. 
Van Vloten and Land, 2, 181-182 ; Philos. Wks. Elwes' translation, 2, 
374. 

Page 26, line 4, " Clerc." Jean Le Clerc, 1657-1736, Professor of 
Philosophy, Belles-Lettres, and Hebrew in the Remonstrant Seminary at 
Amsterdam, 1684-1712, and thereafter of Church History, exercised con- 
siderable influence in the direction of scientific Biblical criticism, and 
wrote several philosophical works ; but his greatest literary influence was 
exercised through the serials or reviews of which he was the editor, 
among which were the "Bibliotheque unfverselle et historique," here 
mentioned; the "Bibliotheque choisie," Amsterdam, 1703-1713; and the 
"Bibliotheque ancienne et moderne," 1714-1726. 

Page 28, line 6, "Understanding."' Of, also, infra, p. 41. The term 
is used in the sense of the Greek vovs, Latin intellectus, to indicate the 
totality of the human intellectual powers, the Reason in the larger sense 
of that term, in the language of Kant and his school, Vernunft. 

Page 42, line 10, "Plato." Schaarschmidt says: "This comparison 
is to be considered as provisional only, in order to illustrate the opposition 
between the author's and Locke's point of view by a familiar example. 
Strictly taken the parallel does not hold good, as may be seen from the 



724 LEIBNITZ'S CRITIQUE OF LOCKE 

addition Leibnitz makes. Aristotle, that is to say, — to call to mind only 
the chief antitheses of the respective theories of knowledge, — assumes 
before all things principles which are peculiar to the spirit as such, while 
Locke denies the same ; Plato, again, recognizes experience by means of 
sense-perception in a wholly different, more real, sense than Leibnitz and 
affirms in no wise, as Leibnitz, an absolute spontaneity of the presenta- 
tive power. 1 ' 

Page 42, line 13, " Acroamatic." Cf. infra, p. 272, note 1. 

Page 42, line 5 from bottom, " Aristotle." Schaarschmidt says : 
"Aristotle has certainly compared the mind (or the Reason — in his 
language vovs), though not the soul in general, with an unwritten tablet." 
Cf Ilepl -irvxvh Bk. III., chap. 4, § 11, Berlin Academy ed., 439b 31 ; 
ed. E. Wallace, Cambridge, 1882, p. 159 : del 5' ovtoos wcnrep ev ypapp-areiup 
iS p.r]dev inrapxet- evre\exeia yey pap.p.ivov oirep crvp.pal.vei ewl rod vov. " This 
meanwhile is by no means to be understood in the sense that thought is 
merely something taken up from without, the spirit a merely receptive 
faculty. According to Aristotle, the thinking spirit is rather partly re- 
ceptive or passive, partly productive or active, as is clear from this same 
Bk. III. of the Ilepl ^ir^s." Cf, also, Zeller, Philos. d. Griech., 3d ed., 
II., 2 [Vol. 4], 566 sq. 

Page 43, line 1, "Schoolmen." The Scholastic philosophy, to which 
Leibnitz frequently refers in this and other works, "assumed," says 
Schaarschmidt, " a three-fold source of knowledge : 1. Experientia, ex- 
perience through the senses ; 2. Batio, the logical faculty of drawing 
conclusions ; 3. Intellectus, the faculty of ideas, which is precisely the 
understanding (or spirit) of Aristotle, active for itself from within, not 
creative out of sense-experience." 

Page 43, line 4, "Prolepses." The Stoics derived general ideas or 
conceptions, — Koival ewotai or TrpoK^eis, communes notiones, — like all 
knowledge, from sensuous perception, explaining them by the persistence 
and combination of the sense-impressions. They are not to be under- 
stood, therefore, in the later sense as innate ideas, independent of ex- 
perience and peculiar to the spirit as such. The Stoic theory was more 
like Locke's than like Aristotle's ; and according to Plutarch, Placita 
philosophorum, IV., 11, considered the soul as originally a blank tablet 
(tabula rasa), upon which the outer world made its impressions. 
Through Boethius [470-524] the Stoic theory of knowledge became the 
source of mediaeval nominalism. On the Stoic doctrine of knowledge, 
cf. Zeller, Philos. d. Griech., 3d ed., Leipzig, 1880, III., 1 [Vol. 5], 70-86 ; 
Benn, Greek Philosophers, 2, 15 ; Windelband-Tufts, Hist, of Philos., 
202 sq. 

Page 43, line 14, "Necessary truths." "Leibnitz," says Schaar- 
schmidt, "here hints at his later more closely grounded division of truths 
into necessary and factual (contingent). The former are, according to 



ADDITIONS AND CORRECTIONS 725 

Leibnitz, the 'eternal truths of reason,' partly logical laws, partly general 
notions which belong to the mind as such, and are developed out of itself 
in order to come into consciousness. The latter, the factual truths, are 
formed by us through abstraction from experience, and therefore real. 
To this antithesis, further developed in the second book, Kant joins on 
that of the so-called a priori and a posteriori thought, in that he assigned 
to the former the character of necessity and universality, to the latter 
that of contingency and actuality (particularity)." 

Page 44, line 13, "Innate." Leibnitz, in here maintaining that expe- 
rience can never furnish anything absolutely and universally valid, and 
is therefore incapable of serving as the foundation of the sciences dealing 
with and requiring absolutely universal fundamental truths, such as 
Logic, Metaphysics, and Ethics, indicates in the sharpest and clearest 
manner his opposition to Locke's theory of knowledge. 

As regards the nature of these pure truths of reason and the method by 
which they arise in consciousness, Leibnitz assumes and maintains that 
they are developed by the mind out of itself, and thus come into conscious- 
ness. Of this self-development, "this transition from potentiality to 
actuality (a potentia ad actum),'''' sense-experience furnishes the occasion, 
but is not the sufficient reason. Leibnitz to this extent, therefore, main- 
tains against Locke the "Innateness of Ideas." But "he oversteps this 
idealistic principle in so far as he assumes an absolute spontaneity of the 
understanding, while at the same time that the understanding itself in its 
development is plainly shown in reciprocal action-with. experience, which 
forms the expression of real relation to other beings. In Leibnitz's 
theory the ' eternal ' and ' necessary ' truths of reason are in substance 
the principles of all knowledge, and furnish accordingly not only the 
ground-principles of the formal sciences, like Logic and Mathematics, but 
also of Metaphysics and Ethics " (Schaarschmidt) . 

Page 44, line 9 from bottom, "The same reasons hold good." Cf. 
H. S. Reimarus, 1694-1768, Allgemeine Betrachtungen iiber die Kunst- 
triebe der Thiere, 1760, 4th ed. 1798, chap. 2, who, says Schaarschmidt, 
has treated the antithesis between the knowledge of man and brute, 
the investigation of which in our times has led to interesting contro- 
versies, better than most of the later writers. Leibnitz assumes a specific 
difference between the souls of brute and man, and does not at all agree 
with Descartes' view that animals are living but soulless automata. On 
animal intelligence, cf. Romanes, Animal Intelligence [International Sci- 
entific Series, Vol. 44, D. Appleton & Co., New York, 1st ed. 1883, 2d ed. 
1886]; Mental Evolution in Animals, New York, 1884, D. Appleton & Co. ; 
Win. Wundt, Lectures on Human and Animal Psychology, translated 
from the 2d German edition, by J. E. Creighton and E. B. Titchener, 
London and New York, 1894, Lectures 23, 24, pp. 340-366. Wundt's 
Lectures include some criticism of Romanes, as somewhat wanting in 
critical attitude and exhibiting too much sympathetic imagination. 



726 LEIBNITZ'S CRITIQUE OF LOCKE 

Page 45, line 6 from bottom, " Intellectual ideas." Intellectual, i.e. as 
opposed to "sensuous" (i.e. belonging to, or arising from, the senses). 
Leibnitz means to say, says Schaarschmidt, either we fasten our attention 
upon sense-pictures, whose source is sense-perception, or upon intellect- 
ual, verstandesmassigen (formulated, sprachgeformten), ideas, thought- 
pictures, for whose rise those general ideas, which Kant called Kategories 
or original notions of the understanding, are requisite ; general ideas 
which do not arise from experience through the senses, but must belong 
to our understanding as such and therefore be considered as "innate" or 
"implanted." 

Page 46, line 18, " Virtual." I.e. Potential, or, as opposed to " actual," 
the real-possible. " It is here," says Schaarschmidt, "the faculty through 
which a substance (the soul) out of its own supreme power goes over into 
a new condition as for it a new realization. Our soul contains an unend- 
ing number of possible ideas, as capacities, seeds or traces left behind and 
remains of former activity, which upon definite occasion it realizes, i.e. 
calls into consciousness. This Leibnitzian application of the — originally 
wider — Aristotelian concept of power to the soul has become for modern 
philosophy in the highest degree weighty and fruitful." 

Page 46, line 7 from bottom, " Reminiscence." On the Platonic doc- 
trine of " reminiscence " or " recollection" (avd/.iv7)<ns), an essential part 
of his doctrine of Ideas, cf. Windelband-Tufts, Hist, of Philos. pp. 118, 
119; Zeller, Philos. d. Griech., 4th ed. 1889, II., 1 [Vol. 3], 823, 824, 
835, 836. 

In Plato's philosophy the ideas which are the objects of our rational 
thought were intuited by the soul in its pre-existent and exalted state 
when it dwelt in the presence of the archetypal forms (irapadeiynara), 
which Plato called ideas (ei'517 or t'Secu). The soul in its eartbly life is 
but dimly, if at all, conscious of these archetypal forms, till the percep- 
tion of their imperfect copies in corporeal things arouses the slumbering 
recollection and stimulates the soul to reproduce them in consciousness 
and with the aid of dialectic again to attain the knowledge of true and 
ideal reality. Cf, also, New Essays, Book I., chap. 1, § 5, Th. (3), infra, 
p. 79 

Page 47, line 8, "Reflection." "Provided," as Schaarschmidt says, 
' ' that Reflection, which with Locke has to do only with the activities of 
the inner nature as such, receives that further content which embraces 
the ' eternal ' and ' necessary ' ground-truths, and to which we are in fact 
led if we keep in mind the presuppositions and modalities under which 
those activities proceed." 

Page 47, lines 18, 19, " The book of Boyle against absolute rest." Cf. 
infra, p. 324, note 2. The treatise is also found in Vol. 1 of the Latin 
version of his works, Opera varia, Geneva, 1680, and later, with the title 
Dissertatio de intestinis motibus particularum solidorum quiescentium, in 
qua absoluta corporum quies in disquisitionem vocatur. On Boyle, cf. 



ADDITIONS AND CORRECTIONS 727 

Lasswitz, Gesch. d. Atomistik, 2, 261-293 ; Lange, Gesch. d. Materialis- 
mus, 2d ed. Iserlohn, 1873. 1, 255; English translation, Boston, 2d ed. 
1879, 1, 299-306. 

Page 47, line 21, "Doing away with atoms." Leibnitz rejects atoms 
in favor of his own monads, because the monads contain in themselves the 
principle of motion as active force, while the atoms are assumed in conse- 
quence of a force in movement foreign to them. On Leibnitz's view and 
its development, cf. Lasswitz, Gesch. d. Atomistik, 2, 470 sq. 

Page 48, line 7 from bottom, "Confused in the parts." Cf. infra, 
pp. 120, 317, note 2, 319, 320, 458, 459. Leibnitz's doctrine of "minute 
perceptions" or, in the philosophical language of to-day, "unconscious 
mental states," is of the greatest significance in psychology and episte- 
mology, and never more so than at the present time. For an excellent 
exposition of it, cf. Windelband-Tufts, Hist, of Philos., pp. 423 sq., 462 sq. 

Page 48, last line, "Hippocrates." Cf. infra, p. 476, note 2. 

Page 49, line 15, " Sufficiently distinguished." That is, to reach con- 
sciousness. The perceptions are not sufficiently strong to call forth a 
conscious activity of the soul. 

Page 49, line 12 from bottom, "Author of the most excellent of dic- 
tionaries." The reference is to Bayle. Cf. infra, p. 507, note 1. 

Page 49, note 1. The note should read: Cf. Vergil, Georg. IV., 393. 
Gerhardt's reading: "que" is evidently a typographical error. Erdmann 
and Janet read : " qnce mox futura," etc.; Jacques, correctly: qiice mox 
ventura trahantur." 

Page 50, line 15, " Pneumatology. " Cf. infra, p. 362, note 2. 

Page 50, line 20, " Law of Continuity.''' 1 Cf. infra, p. 334, note 1; 
p. 552. 

Page 50, note 3. Add : The correspondence of Leibnitz and Basnage 
is found in Gerhardt, Leibniz, philos. Schrift., 3, 73 sq. 

Page 51, line 7, " Numero." Cf., also, infra, p. 332, note 1. 

Page 51, lines 11-13, "Perfect globes of the second element, born of 
cubes perfect and original." The reference is to Descartes, Principice 
Philosophise, Pt. III., §§ 48 sq. Cf, also, Neio Essays, infra, p. 552, 
note 1. Mahaffy, Descartes, Blackwood's Philosophical Classics, Edin- 
burgh, 1881, p. 159, says Descartes' theory of general physics was elabo- 
rated as regards minerals. This fact perhaps accounts for Schaarschmidt's 
translation : " des sichtbaren Metalls " and his reference to Prin. Philos., 
Pt. IV., §§ 70, 75, in his note, Erlduterung, 400, p. 101, to the passage, 
New Essays, Bk. IV., chap. 16, § 12, Th., p. 532 of his German transla- 
tion. Descartes, says Mahaffy, ibid., p. 159, gave special explanation 
of the growth of the human body, but that of plants and the lower 
animals was wanting when he died. On Descartes' theory, cf. Lasswitz, 
Gesch. d. Atomistik, 2, 89. 



728 LEIBNITZ'S CRITIQUE OE LOCKE 

Page 51, lines 19, 20, "Present considerations." While the process of 
abstraction allows ns, in order to their better apprehension, to concen- 
trate our attention for the time on certain properties or attributes of a 
subject to the exclusion of others, yet we must remember that in so doing 
we are departing from reality and only partially representing it in con- 
sciousness. 

Page 51, line 20. Instead of the rendering : "If it were very well 
understood," read, after Schaarschmidt, " If we take it as pure and 
simple gospel," etc. 

Page 51, line 29, "Some exception." Nature gives us no perfect 
circles, perfect spheres, etc. Perfect mathematical regularity of form 
exists only in thought. 

Page 52, line 7 from bottom, "Strong-minded." That is, the "Free- 
thinkers," as Leibnitz at other times called them, who thought they might 
deny immortality itself after the pretended proofs for it given by Scholas- 
ticism had been disproved. 

Page 53, line 8 from bottom, " Averroists and some bad Quietists." 
Cf. infra, p. 581, note 1. The Mystics and Quietists approached very 
nearly this Averroistic doctrine of a denial of personal immortality. In 
Leibnitz's time the Mystics and Quietists were especially the followers of 
Madame Guy on, who was ready "to burst from an overplus of divine 
grace," and of Ant. Bourignon, on whom cf. infra, p. 599, note 2 ; also, 
according to Schaarschmidt, Leibnitz's letter CXLIV., Feder, Commercii 
epistolici Leibnitiani, Hanover, 1805, p. 459. 

Page 54, note 1. Add : Leibnitz was much interested in the Locke- 
Stillingfleet controversy, as his correspondence with Thomas Burnett 
shows. Cf. Gerhardt, Leibniz, philos. Schrift., 3, 149-329, passim, and 
especially pp. 205, 216, and the two essays, pp. 223-242 ; also Eoucher 
de Careil, Lettres et opuscules inedits de Leibniz, Paris, 1854, Introduc- 
tion, pp. lxii sq., and Leibnitz's Bemarques sur le Sentiment de M. de 
Worcester et de M. Locke, ibid., pp. 1-26. The latter piece is identical 
with that published — not therefore for the first time — by Gerhardt, op. 
cit., 3, 229-242. The controversy, like that of Leibnitz and Arnauld, 
served to bring Locke to the further explication and limitation of his 
views. 

Page 55, lines 16, 17, "French version." That is, by Pierre Coste, 
with the co-operation of Locke. It appeared in 1700, then in 1729, and 
again in 1742. Cf. ante, p. 4, note 1. For the correspondence of Leib- 
nitz and Coste, cf. Gerhardt, Leibniz, philos. Schrift., 3, 377-436. Before 
Locke published, in 1690, his Essay, he published an abstract, translated 
into French by Le Clerc in Le Clerc's " Bibliotheque universelle," Janu- 
ary, 1688. Cf. ante, p. 4, note 1, and Fraser's Locke's Essay, 1, 15, 
note 2. The abstract or " Epitome " is found in Lord King's Life and 
Correspondence of Locke, new ed., London, 1830, 2, 231-293 ; Bonn's ed., 
1858, 1 vol., pp. 365-399. 



ADDITIONS AND CORRECTIONS 729 

Page 55, last line, " Intentional species." Cf. infra, p. 381, note 1. 

Page 56, line 3. For the Latin verse, cf. Ovid, Tristia, I., 8, 7. 

Page 59, line 4 from bottom, " Inexplicable qualities." That is, the 
qualitates occultce of the mediaeval philosophers. 

Page 60, line 6 from bottom, " Instructive." Leibnitz, as Schaar- 
schmidt says, "avails himself of Stillingfleet's polemic against Locke, 
which is of particular interest because it shows Locke's uncertainty in 
regard to the weighty question of the substantiality of the soul, to add 
thereto the statement that the soul must be immaterial. Locke himself, 
so he argues, has admitted that thought is not conceivable as a modifica- 
tion of matter, or that, in other words, a thinking being cannot be a mere 
mechanism ; thus the soul is to be considered as something immaterial, 
since the thought, that God may through a miracle have bestowed thought 
upon matter, is an impermissible subterfuge." For further discussion of 
the point, cf. New Essays, Bk. IV. 

Page 62, line 10 from bottom, " Miracle pure and simple." Cf. infra, 
p. 428. The doctrine of a purifying fire through which souls have to pass 
after death goes back to the early period of the church, but became more 
prominent and was more generally adopted from the time of Gregory the 
Great (c. 540-604). Cf. Hagenbach, Hist, of Doctrines, ed. H. B. Smith, 
§ 141, Vol. 1, p. 373 ; § 206, Vol. 2, p. 126. Clement of Alexandria, Stro- 
mateis, vii., 6, says: <pa.p.Zv b" r)p.els dyidfciv rb irvp, ov t<x Kpia, dWd rds 
dfiaprcoXovs \pvxds ' irvp ov rb irdp,(payov nal fidvavaov, dXXa rb cppbvip.ov 
\iyovres, rb 5uKvovp.ei>ov did \pvxys rrjs di.epxop.evr]s rb irvp, i.e. " We say that 
fire sanctifies not flesh, but sinful souls, speaking of that fire which is 
not all-devouring, such as is used by artisans, but of that which is dis- 
criminative, pervading the soul which passes through the fire " (the phrase 
"discriminative" (<pp6vip.ov), or as Bigg, The Christian Platonists of 
Alexandria [Bampton Lectures for 1886], p. 113, translates it, "wise fire," 
"comes," says Bigg, "from Heraclitus and the Stoics.") Cf. Bigg, op. 
cit., 295; Hagenbach, op. cit., § 77, 1, 222. And Augustine, De Civit. 
Dei, Bk. XXL, chap. 10, Benedictine ed., Paris, 1685, Vol. 7, p. 631, 
says : " Cur enim non dicamus, quamvis miris, tamen veris modis etiam 
spiritus incorporeos posse poena corporalis ignis affiigi, si spiritus homi- 
num, etiam ipsi profecto incorporei, et nunc potuerunt includi corporali- 
bus membris, et tunc poterunt corporum suorum vinculis insolubiliter 
alligari ? " i.e. "For why may we not assert that even immaterial spirits 
may, in some extraordinary way, yet really be pained by the punishment 
of material fire, if the spirits of men, which also are certainly immaterial, 
are both now contained in material members of the body, and in the 
world to come shall be indissolubly united to their own bodies ? " ( The 
City of God, 2, 435, translated by Rev. Marcus Dods, M.A., T. & T. Clark, 
Edinburgh, 1871). In chapter 7, after having in previous chapters cited 
many real or supposed facts from the natural world in support of the pos- 
sibility at least of the view, he admits that it is miraculous and beyond our 



730 LEIBNITZ'S CRITIQUE OF LOCKE 

knowledge, and maintains the omnipotence of God as the ultimate reason 
for belief in miracles. Thos. Aquinas, Summa Theol, Quaest. 70, Art. 3, 
Concl.,says: " Respondeo : Dicendum quod ignis inferni [i.e. purgato- 
rial fire, according to the context] non sit metaphorice dictus, nee ignis 
imaginarius, sed verus ignis corporeus," etc. Only those requiring purga- 
tory go there, according to St. Thomas, cf. Qusest. 69, Art. 2. Bellamin, 
1542-1621, in his De Purgatorio, chaps. 10-12, investigates the method 
of the purgatorial fire and follows Augustine in teaching that it is mate- 
rial and miraculous in its action upon the soul. 

Page 63, line 10 from bottom, "Demons or goblins." "Leibnitz is 
perhaps here thinking," says Schaarschmidt, "of the so-called Spirits of 
the Elements (Elementargeister), of which the 'philosophers and physi- 
cians of the past,' especially Theoph. Paracelsus [cf. infra, p. 645, note 1], 
had treated, both in his Philosophic/, sagax, and in a special book, De 
nymphis, sylpihis, pygmceis et salamandris, or even of the ' spiritus famili- 
aris ' of others, as of the Italian philosopher and physician Hieronymus 
Cardanus [cf. infra, p. 566, note 1], who in his interesting autobiography 
[Be vita propria"], chap. 47, discusses the subject and at the same time 
narrates marvellous experiences of his own past life." 

Page 63, note 3. Add: In the Philos. Mosaica, and also in his 
Utriusque Cosmi — 31'etaphysica, physica atque technica Historia, Oppen- 
heimii, 1617 fol., "God appears," says Schaarschmidt, "as the ani- 
mating and moving principle of things, in that all power streams forth 
in a miraculous way from him into matter, in order afterwards to turn 
back again from the thereby occurring differentiation to unity." On 
Eludd, cf. Lasswitz, Gesch. d. Atomistik, 1, 329 ; Stockl, Q-esch. d. Philos. 
d. Mittelalters, III. [Vol. 4], 472-476. 

Page 64, note 1. Add : Prof. A. C. Fraser, in his edition of Locke's 
Essay concerning Human Understanding, Oxford, 1894, follows Coste's 
French version in separating the introductory chapter from the First Book, 
and making, with Leibnitz here, but three chapters in Bk. I. 

Page 64, note 2, line 2. After "1674," add: new ed. with notes by 
Bouillier, Paris, 1880,2 vols. ; line 4, after " Bernier," add: On Gassendi, 
cf. Stockl, Gesch. d. Philos. d. Mittelalters, III. [Vol. 4] 316-327 ; Lange, 
Gesch. d. Mater ialismus, 2d ed., Gerlohn, 1873, 1, 223-234, Eng. trans. 2d 
ed. 1, 253-269 ; Lasswitz, Gesch. d. Atomistik, 2, 126-188. On Bernier's 
later divergence from Gassendi, cf. ibid. 2, 504. 

Page 65, line 13. Instead of " Doctors," read: " scholars." 

Page 65, note 1. Add: Lady Masham, 1659-1708, was one of Locke's 
most intimate and truest friends, kept him by her at her country seat at 
Oates and nursed him in his last illness. Cf. Gerhardt, Leibniz, philos. 
Schrift. 3, 365. Lady Masham presented Leibnitz with a copy of her 
father's Intellectual System, as appears by his letter of March 29, 1704, cf. 
Gerhardt, 3, 338. 



ADDITIONS AND CORRECTIONS 731 

Page 65, note 3. Add : The objections referred to in the text are the 
objectiones quintce against Descartes' Meditationes de prima philosophic, 
"which indeed," as Schaarschmidt says, " contain a series of very acute 
objections and gave Descartes much trouble." The Cinquiemes Objec- 
tions of " Gassendy," with the Beponses of Descartes thereto, are found 
in Cousin, (Euvres de Descartes, 2, 89 sq., 2.41 sq. 

Page 66, line 6, " Inclined towards ethics." Leibnitz, who to a certain 
extent may be considered as giving utterance to his own views in the 
person of Theophilus, here throws out a hint to be well taken to heart as 
regards his own course of development. As a natural consequence of his 
early studies in jurisprudence, Leibnitz was led to a deeper study of ethical 
conceptions, and in like manner his study of Descartes made him 
acquainted with the problems of mathematics and physics, which he 
thoroughly examined only later after his sojourn in Paris. 

Page 66, lines 13, 14, "No longer a Cartesian." Cf. the entire context, 
pp. 66-69, also Leibnitz's letter to Remond de Montmort, January 10, 
1714, Gerhardt, Leibniz, philos. Schrift. 3, 606-607, Erdmann, 701-702, in 
which Leibnitz gives a brief account of his own philosophical studies and 
development, including, Plato, Aristotle, and the Scholastics and thence 
passing to the moderns, rejecting the "substantial forms " for the mechan- 
ism of the Cartesian system, and then developing his own doctrine of Pre- 
established Harmony. The difficulties and controversies within the 
Cartesian School and against it led Leibnitz to his own doctrine, and he 
remarks in his Considerations sur le Principe de Vie, 1705, Gerhardt, 6, 
540, Erdmann, 430, as also in the letter here cited, that if Descartes had 
known that Nature conserves not only the same force, but also the same 
total direction in the laws of motion, he would himself have come to the 
system of pre-established harmony. Cf. W. Sigwart, Die Leibniz'' sche 
Lehre v. d. prastabilirten Harmonic. Tubingen, 1822, pp. 110-112, 117, 
118, 121, 132, etc. For Leibnitz against Descartes and Cartesianism, cf. 
Gerhardt, 4, 265-406 ; also, Stein, Leibniz u. Spinoza, 60 sq. 

Page 66, line 17, "New System." That is, The System of Pre- 
established Harmony, in explanation and defence of which Leibnitz 
published in the journals mentioned many essays, most, if not all, of which 
are mentioned later in either the text of the New LJssays or notes thereto. 
"Leibnitz," as Schaarschmidt well says, "can truly boast that he has 
turned to account for his own system moments of all the doctrines named 
in the text," it being "a characteristic feature of Leibnitz's thought to 
ascribe a relative truth to each philosophic system and accordingly to wish 
to extract from it a good side in order, by harmonizing these different 
elements, to bring to pass the possibly best view of the world." Cf. 
Leibnitz's letter to Eemond de Montmort, January 10, 1714, Gerhardt, 
Leibniz, philos. Schrift. 3, 606, Erdmann, 701 : " Outre que j'ay eu soin 
de tout diriger a l'edification, j'ay tache de d^terrer et de re"unir la vdrite 
ensevelie et dissip^e sous les opinions des differentes Sectes des Philosophes, 



732 LEIBNITZ'S CRITIQUE OF LOCKE 

et je crois y avoir adjoute quelque chose du mien pour faire quelques pas 
en avant." 

Page 66, note 1. Add : Geronimo Rorario, 1485-1566, an Italian 
litterateur, Nuncio of Clement VII. at the Court of Ferdinand, King of 
Hungary, maintained, against the Cartesians and the followers of Aristotle, 
that the beasts have reason and make better use of it than man. His book, 
Quod animalia bruta scepe ratione utantur melius homine, appeared first 
in 1648, then 1654 at Amsterdam. 

Page 67, lines 3, 4, "Life and perception in all things." The doctrine 
of the universal soulhood (Allbeseeltheit) goes back to the world-soul of 
Plato, as developed especially by Plotinus (cf. Windelband-Tufts, Hist, of 
Philos., 245 sq.), and is connected in part therewith, and partly with the 
pantheistic tendencies represented, for example, by the Averroists (cf. 
New Essays, infra, p. 581, note 1). Leibnitz rejects both errors by his 
Monadology, which conceives the universal soulhood of substances in an 
individual and not in a pantheistic way. In modern times the doctrine 
appears in Giordano Bruno, 1548-1600 (cf. Delia Causa, Vol. II., pp. 239- 
241, ed. A. Wagner, Leipzig, 1829, new ed. by P. de Lagarde, 2 vols., 
Gottingen, 1888, German trans, by Lasson, Berlin, 1872, in J. H. v. Kirch- 
mann's Philos. Bibliothek, Vol. 53), and in Jacob Boehme (cf. infra, 
p. 298, note 1). On the doctrine as found in Bruno and Boehme, cf. 
Windelband-Tufts, op. cit., 367 sq., 373 sq. Spinoza, Ethica, Pt. II., 
Prop. XIII. , Scholium, ed. Van Vloten and Land, 1, 86-88; Elwes' 
trans., 2, 92, also gives expression to the same thought. 

Page 67, line 5, "Countess of Connaway." Anne — Viscountess Con- 
way — died Feb. 23, 1678-9, was a metaphysician and an earnest student 
of Plato, Plotinus, Philo Judseus and the " Kabbala Denudata." In spite 
of never-ceasing sufferings from a severe headache lasting till her death, 
she pursued her metaphysical studies with extraordinary devotion and 
assiduity. Her physician, Francis Mercury van Helmont (cf. infra, 242, 
note 2), encouraged her in this course. She was very friendly with H. 
More and corresponded with him on philosophical and theological topics. 
She wrote many works of which only one has been printed : Opuscula 
philosophiea quibus continentur principia philosophice antiquissimce et 
recentissimce, Amsterdam, 1690. It was the first in a collection of philo- 
sophical treatises appearing in Latin in that year at Amsterdam, translated 
as "a work by a certain English countess, 'learned beyond her sex,' " 
and ascribed by Leibnitz in a German literary journal, on the authority of 
Van Helmont, to the Countess of Conway. The treatise was re-trans- 
lated into English and published with the title The Principles of the Most 
Ancient and Modern Philosophy, etc., London, 1692, 8vo. 

Page 67, note 1. Add: On Campanella, cf. Stockl, Gesch. d. Philos. d. 
Mittelalters, III. [Vol. 4.], 343-366 ; Lasswitz, Gesch. d. Atomistik, 1, 340- 
342. 

Page 67, note 2. Add : On Van Helmont, cf. infra, p. 242, note 2 ; on 
H. More, cf. infra, pp. 380, note 1 ; 382, note 2, and addition thereto, 
infra p. 768. 



ADDITIONS AND CORRECTIONS 733 

Page 67, note 3. Add: Further references to Archfeus in Leibnitz's 
writings are: Specimen Dynamicum, Gerharclt, Leibniz, math. Schrift., 
II., 2 [Vol. 6], 242, also infra, Appendix, p. 679 ; Hypothesis phys. nova, 
Theoria motus concreti, § 60, Gerhardt, Leibniz, philos. Schrift. 4, 217 ; 
math. Schrift., II., 2 [Vol. 6], 57; Dutens, Leibnit. op. om., 2, Pt. II., 
33 ; Leibnit. Animadversiones circa Assertiones aliquas Theorice 3Iedicce 
verce Glar. Stahlii, Dutens, op. cit., 2, Pt. II., 136. Cf, also, Windel- 
band-Tufts, Hist, of Philos. 371 sq. 

Page 68, line 10, " Morte carent animce.' 1 '' Cf. Ovid, Metamorphoses, 
15, 158. 

Page 68, line 20, "Spontaneity." Leibnitz ascribes absolute spon- 
taneity to the soul, to which the activity of the body perfectly corresponds 
through the Pre-established Harmony, and therefore neither influences 
nor disturbs it. 

Page 68, line 7 from bottom, "Epitome." That is in the Monad, each 
monad representing in itself and to itself the entire universe. Leibnitz 
constantly recurs to this thought, which is one of the chief points of his 
system. Cf. Systeme nouveau de la nature, § 16 ; Monadologie, § 65, etc. 

Page 69, note 1. Add : also G. Croom Robertson, Philos. Bemains, 
Williams & Norgate, 1894, pp. 334-342. 

Page 70, line 5 from bottom, " Copernicans." Kant, later in the 
Preface to the 2d ed. of his Kritik d. reinen Vernunft, makes use of the 
same comparison of Copernicus. 

Page 71, line 24, " Confused perceptions." Cf. ante, p. 48 and note to 
line 7 from bottom, ante, p. 727. " While Leibnitz," says Schaarschmidt, 
"often returns to this antithesis of truths of reason and of fact, he has 
unfortunately nowhere given accurate definitions of the former, nor any 
wholly satisfactory criterion of a truth of reason. Kant first undertook 
this task, in that he certainly on the one side significantly restricted the 
service of the truths of reason, on the other, that against Leibnitz he 
recognized that for the reason as such complete (fertige) concepts are to 
arise out of the truths of reason. ' ' 

Page 72, note 1. Add : " The Later Arminians," says Schaarschmidt, 
" are here referred to, as the leaders of this religious sect, such as Episco- 
pius, Limborch, J. Clericus, like Descartes and Leibnitz himself, assume 
a knowledge of God derived from natural reason." 

Page 74, line 8 from bottom, "Natural light." Cf. infra, pp. 575-576, 
note 1. 

Page 74, lines 4, 3, from bottom, " Verification." Cf. ante, p. 71, note 
to line 24, above, and also New Essays, Bk. IV., chaps. 9, 11. Leibnitz 
here presents as the criterion or test of innate ideas their immediacy in 
consciousness. Spinoza before him (Ethica, Pt. II., Prop. 43, Scholium, 
ad fin., ed. Van Vloten and Land, 1, 111 ; Elwes' trans., 2, 115 ; cf, also, 
F. Pollock, Spinoza, his Life and Philosophy, 129 sq.), said : " Sane sicut 



734 LEIBNITZ'S CRITIQUE OF LOCKE 

lux seipsam et tenebras inanifestat, sic Veritas norma sui et falsi est." 
Cf, also, Descartes, Prin. Philos., Bk. I., § 45 ; ed. Cousin, 3, 90; Veitch's 
trans., 212, where he sets forth the doctrine of "clear and distinct" 
knowledge and of intuition through which we become immediately con- 
scious of the truth as such. Cf, also, Descartes, Begulm ad directionem 
ingenii (Begles pour la direction de V esprit), Opuscula posthuma Cartesii, 
Amsterdam, 1701, III., p. 6; IV., p. 9; VI., p. 14 ; ed. Cousin, 11, 209, 
215, 226. 

Page 75, note 1. Dele note. The Ludolph here referred to by Leibnitz 
is Ludolph van Ceulen, or Keulen, 1539-1610, Professor of Military Archi- 
tecture in the University of Leyden since 1600, and previously teacher of 
mathematics in Breda, Amsterdam, and Leyden. He published his Van 
de Circkel, daarin geleert wird te finden de nazste proportie des Circkels- 
diameter tegen synen Omloop, Delft, 1596 ; Latin trans, by Snellius, en- 
titled Be circulo et adscriptis, 1615. His De arithmetische en geometrische 
fondamenten, etc., Leyden, 1616. Fundamenta aritlimetica et geornetrica 
and Zetemata (sen Problemata) geornetrica, both trans, from the Dutch 
by Snellius, Lugd. Bat., 1615. He computed the ratio of the diameter 
to the circumference of the circle to 35 places of decimals. The ratio 
is commonly known in Germany by the name " Ludolphische Zahl." 
Leibnitz refers to him in his mathematical writings, cf. Gerhardt, Leibniz, 
math. Schrift. II., 1 [Vol. 5], 95, 119. For Leibnitz's discussions of the 
subject, cf. infra, p. 424, note 2. 

Page 77, line 6 from bottom, " Subvenire." Schaarschmidt translates 
"Beikommen," and in his note to the passage states that "the French 
souvenir (to remember) made from subvenire, originally means : to come 
to the aid of. The expression of help introduced by the Herbartian phi- 
losophy could, unfortunately, not be used, since the word-play would be 
wholly lost." 

Leibnitz's thought is that reminiscence, the active and voluntary factor 
in the reproduction of the past and in bringing the now unconscious 
knowledge again into consciousness, requires and receives the aid of 
remembrance or memory, the conservative factor in the process, which in 
some unknown and mysterious way, and out of consciousness, preserves 
as in a store-house the knowledge previously acquired or possessed. Cf. 
Hamilton, Metapliys., Lect. 20, pp. 274-275, American ed., Boston, 1875. 

Page 78, line 16 from bottom. The sentence should read thus : "For 
through an admirable arrangement of nature we cannot have abstract 
thoughts which do not require something sensuous, although this should 
consist only of such characters as are the forms of the letters and the 
sounds." 

Page 79, line 8 from bottom, "Opinion of the Platonists." Cf. ante, 
p. 46, and note to line 7 from bottom, ante, p. 726. 

Page 80, note 1. Add: Janet also reads: "ou." Schaarschmidt 
translates " wo," cf. his teanslation, p. 45, line 13 from bottom. The 



ADDITIONS AND CORRECTIONS 735 

context seems to require here the reading "oil," where. The reading 
" ou " is probably a MS. or typographical error. 

Page 83, note 1. Add: For an account of his views, cf. Lasswitz, 
Gesch. d. AtomistiJc, 2, 188-207. Digby's doctrine on the subject men- 
tioned in Leibnitz's text is found in his Demonstratio immortalitatis 
animee rationalis, Tract. I., cap. 3, p. 26 sq., ed. Francofurti, 1664, full 
title of which Lasswitz gives, op. cit., 2, 188, note 3 ; and in his Institu- 
tiones peripatetics, published as an Appendix to the Demonstratio, ed. 
of 1664. Schaarschmidt gives 1st ed. of Demonstratio, Paris, 1655. A 
treatise of the nature of bodies, Paris, 1644. 

Page 86, line 8, " Sadness is." Says Schaarschmidt : " We are imme- 
diately conscious of the theoretical ground-truths as such. With the 
practical, the case is different. Joy and sorrow we certainly feel immedi- 
ately as such, but to find out their real nature requires subsequent reflec- 
tion." 

Page 87, note 2. After " Erdmann," add : Janet ; and after "Bohn's 
edition," add: Fraser's Locke's Essay, 1, 67, line 18. 

Page 88, line 13 from bottom, "Instinct." "Leibnitz understands 
here by instinct," says Schaarschmidt, "a definite inclination to a certain 
manner of action, which arises out of need and serves to satisfy the same. 
' Truths of instinct ' thus refer themselves back to our nature and are 
accordingly, in conformity with Leibnitz's general view, innate truths." 

Page 89, note 2. Add: A German translation, by G. E. Bottger, ap- 
peared at Nordhausen, Gross, 1787. 

Page 89, note 3. Add : According to Schaarschmidt, the story is found 
in Bk. II., chap. 1, p. 73, of Baumgarten's, " very interesting but rare," 
Perigrinatis in JEgyptum, Arabiam, Palcestinam et Syriam, Noribergse 
ex off. Gerlachiana, p. P. Kaufmannum, 1694, 4to. 

Page 91, line 5, " esse.' n Cf. Digest or Pandects, Bk. I., Tit. 1, § 3, 
where Florentinus says: "Ut vim atque injuriam propulsemus. Nam 
jure hoc evenit, ut quod quisque ob tutelam corporis sui fecerit, jure 
fecisse existimetur, et, cum inter nos cognationem quandam natura con- 
stituit, consequens est hominem homini insidiari nefas esse." Corpus 
Juris Civilis Academlcum Parisiense, p. 229, 7th ed., Lutetise Parisiorum 
1862 ; Corpus Juris Civilis (Digesta recog. T. Mommsen, and paged sepa- 
rately), Berlin, Weidmann, 1893, Vol. 1, p. 1. 

Page 91, line 8 from bottom, " Complete certitude to morals." Schaar- 
schmidt here compares Hume, "the most acute (scharfsinnigste) of the 
English philosophers," who "reached a similar result, wholly indepen- 
dent of Leibnitz," in his An Inquiry concerning the Principles of Morals, 
Section I., cf. The Philos. WJcs. of David Hume, 4 vols., Little, Brown, & 
Co., Boston, 4, 233 : " The final sentence, it is probable, which pronounces 
characters and actions amiable or odious, praiseworthy or blamable ; 



LEIBNITZ'S CRITIQUE OE LOCKE 



that which stamps on them the mark of honor or infamy, approbation or 
censure ; that which renders morality an active principle, and constitutes 
virtue our happiness, and vice our misery; it is probable, I say, that this 
final sentence depends on some internal sense or feeling, which nature has 
made universal in the tohole species. . . . But in order to pave the way 
for such a sentiment, and give a proper discernment of its object, it is 
often necessary, we find, that much reasoning should precede, that nice 
distinctions be made, just conclusions drawn, distant comparisons formed, 
complicated relations examined, and general facts fixed and ascertained." 
Cf, also, Hume, A Treatise of Human Nature, Bk. III. Of Morals, 
Pt. I., Sect. II., ed. Green and Grose, 2, 247. 

Page 91, line 3 from bottom, "Boutan." That is, Bhutan, a district 
in the Eastern Himalayas, north of Assam. 

Page 92, line 6, " Often confused." " Feeling here means," as Schaar- 
schmidt says, "not the sensuous-psychical sensation, but the confused 
complex of presentations ( Vorstellungen) — a frequently used significa- 
tion of the term — which occupies the soul and therefore often drives it to 
action. Feelings of this kind may by self-reflection be resolved into more 
or less clear and distinct ideas (Vorstellungen) , a process necessary for 
testing and correctly estimating their content. Leibnitz at this time 
appears to regard all feelings without exception as such undeveloped 
ideas and judgments." 

Page 93, line 20, " Joseph Scaliger." Cf. infra, p. 106, note 2. 

Page 95, note 1. Add : The five principles here referred to are found 
in the De Veritate, and in the Be Beligione Laid, annexed to the 3d ed., 
London, 1645, of the De Verit. Cf. Fraser's Locke's Essay, 1, 80, note 2 ; 
81, note 1. 

Page 96, note 1. After " ad init.," add : 15, Berlin Academy ed., 1106 b 

36 : ianv, dpa i] dperr] e^ts irpoaipeTiKi] ev p.eaoTr\Ti odira. t-j) Trpbs T}p.ds 
wpia/J-evri A6y<£> nal ws dv 6 (ppovifxos bpiaeiev • pLeaoTTjs de duo Kcuawv, ttjs fiev 
nad' vw€pfio\T]v tt]S Se Kar' eWei\f/iv . . . 816 Kara p.ev ttjv ovaiav Kal tov 
\6yov tov t'i ^v eivcu \iyovra p,eo-OTT]s ecrrlv 7] dper-f}, Kara 8£ rb dpiarov Kal to 
ed dKpoTrjs. 

Page 97, note 1. Add: A long time after this note was in type, I 
came across the following in Guhrauer, Leibnitz's Deutsche Schriften, 2, 
509, among some Vermischte Bemerkungen und Urtheile . . . Aus dem 
Monatlichen Auszuge: "(October, 1701). Herr Boileau Bespreaux, ein 
franzosischer Academicus und beriihmter Satyricus, hat eine neue und 
vermehrte Edition seiner Satyren machen lassen, und denselben seinen 
Namen vorgesetzt, und dabey zu verstehen gegeben, dass er diese und 
keine andere Edition vor die seine erkenne." Possibly the edition here 
referred to contained the lines as Leibnitz gives them, the author chang- 
ing them in later editions. 

Page 99, lines 7-9. Cf. ante, p. 66, and note to line 17, ante, p. 731. 



ADDITIONS AND CORRECTIONS 737 

Page 99, note 1. Add : The Chronicon, 379-468, is also found in 
M. Bouquet, Bee. hist. Ganles, new ed., Paris, 1869-1880, 19 vols., fol., 
Vol. 1, p. 612; A. Duchesne, Hist. Franc. Script., 1, 183; Migne, Patrol. 
s. Lat., 74, 675. 

Page 100, lines 16, 17. "The knowledge of being is wrapped up in 
that knowledge which we have of ourselves." Cf. New Essays, Bk. II., 
chap. 27, § 9, Th., infra, pp. 245 sq., and note to p. 247, lines 7-9, infra, 
p. 760. Also Kant's doctrine of the categories, to which Leibnitz's 
thought at this point is very closely related. Our self-consciousness gives 
us an immediate knowledge of being, i.e. of our own particular being, 
but not yet the concept of being or substance in general nor any ' ' eternal 
truth." What is given is an internal experience, whose essential and 
necessary content, implications and full significance are reached only after 
profound and protracted thought. 

Page 101, note 1. The following changes or corrections are to be made 
in this note : In line 23, instead of "Appendix," read : Duncan, 37-40 ; 
in line 25, after '■'■Math. Schrift., 6, 234 sg.," insert: trans., Appendix, 
infra, pp. 670-692 ; in line 27, instead of "Appendix," read: Duncan, 
71-80; in line 28, instead of " Appendix," read : Duncan, 112-126 ; in 
line 30, dele " trans., Appendix " ; line 5 from bottom, " As Leibnitz was 
occupied," etc., cf. infra, p. 531, note 2, HT2, 3. The statement made 
in these two notes would probably more nearly represent the truth in the 
matter if made thus : "As Leibnitz was occupied with the composition 
of his 'New Essays' from 1700-1704, and with their revision until the 
end of 1707, and perhaps later (cf. Gerhardt's Introduction to the 'New 
Essays,' ante, pp. 8, 9, and Leibnitz's Correspondence with Coste, Ger- 
hardt, Leibniz, philos. Schrift., 3, 377 sq., especially 391-400) the relative 
date," etc. 

Page 103, line 7, "Witsen." Nicolas Witsen, c. 1640-1717, Dutch 
ambassador at the Russian Court, alderman and burgomaster at Amster- 
dam, published Architectonica nautica nov-antiqua, Amstelod., 1671 ; 
Noord-en Oost-Tartarye, met Landkaerten, beschreven, getekent, etc., 
2 vols., fol., ib., 1692 and 1705. Eor Witsen' s correspondence with 
Leibnitz, cf. Dutens, 6, Pt. II., 199-203 ; Eoucher de Careil, CEuvres de 
Leibniz, 7, 450, 453-459, 464. 

Page 103, line 8, "Barantola." The old name for Lhasa, the capital 
of Thibet. Cf. Dutens, 6, Pt. II., p. 201. 

Page 103, note 2. Add: Chap. 3 in Eraser's Lockers Essay. 

Page 103, note 3. Add : Eraser's Locke's Essay, 1, 99. 

Page 105, note 1. Add: Cf. Fraser's Locke's Essay, 1, 109. Eraser 
numbers 21, and states in his note that the section was added in the 
second edition 

Page 108, note 2, line 5 from bottom. Instead of "Vol. 3," read: 
III., 2 [Vol. 6]. 
3b 



738 LEIBNITZ'S CRITIQUE OF LOCKE 

Page 109, note 2. Cf. ante, p. 733, note to p. 68, line 7 from bottom. 
Leibnitz regards each monad, and especially the human soul, as a mirror 
of the universe. So far as the ideas are clear and distinct, the soul ex- 
presses the picture of the ideal universe existing in the mind of God as 
the ' ' best world ' ' and realized out of his goodness ; so far as they are 
confused, the soul is like the phenomenal world in space and time. 

Page 110, lines 18, 19, " Intrinsic connotations.' 1 '' The intrinsic, inner 
activity of every " substantial thing" determines its external activity and 
relations to each and all other things. In Leibnitz's view, this activity 
consists in representation or is conceived as analogous to representation. 
That is, all external change is apparent merely, depending upon that in- 
ternal change in the condition of substances which we call representation 
and which is the real occurrence. 

Page 112, line 11 from bottom, "Certain author." Locke, Bk. II., 
chap. 1, § 10 (in Coste's translation, which, it will be remembered, was 
the one used by Leibnitz as the basis of his critique, 4th ed., Amsterdam, 
1742, p. 65, 4 vol. ed., Amsterdam, 1774, 1, 152), says: "Car il s'est 
trouve' un Auteur qui ayant lu la premiere Edition de cet Ouvrage, et 
n'6tant pas satisfait de ce que je viens d'avancer contre l'opinion de ceux 
qui soutiennent que VAme pense toujours, me fait dire, qa'une chose cesse 
d'exister parceque nous ne sentons pas qitfelle existe pendent notre som- 
meil" etc.; but he does not name the author referred to. In the English 
editions of the Essay, for example, Bonn's, Vol. 1, p. 212 ; Fraser's, Vol. 
1, p. 129, Locke makes the reference general : " How could any one make 
it an inference of mine," etc. Philalethes rightly takes exception to the 
opinion thus falsely imputed to the partisans of Locke. 

Page 118, line 10 from bottom, "Beg the question." Schaarschmidt 
has put the argument in logical form thus : " That of which we are not 
conscious is not in the soul ; We are often conscious of no ideas ; there- 
fore, We are often without ideas (or, therefore, often we do not think). 
And he goes on to say that, the circle, of which Leibnitz speaks, consists 
in the fact that he who so concludes has already put the conclusion in 
the major premise in assuming that to have no consciousness of ideas is 
the same as to be without ideas (Nichtvorstellen) or not to think (JSficht- 
denken). The latter statement is false. One can have ideas, and actu- 
ally does have them, without being directly conscious of his ideas 
(Vorstellens). Thus the major premise of that argument is false, and 
therefore the conclusion likewise, while the minor is true. According to 
Leibnitz, substance is always active — is indeed action itself — thus also 
the soul, since for him it is a substance, and since the proper activity of 
the soul is to have ideas (das Vorstellen), therefore the soul is always 
having ideas (yorstellend) ." 

Page 118, note 1, line 2. After "Erdmann," add: Janet. 

Page 119, line 8 from bottom, "Independently of the senses." Cf. 
ante, p. 723, note to p. 42, line 10, ad fin. : p. 725, note to p. 44, line 13 ; 



ADDITIONS AND CORRECTIONS 739 

p. 733, note to p. 68, line 20. In accord with Leibnitz's principle of the 
absolute spontaneity of substances, all activity, that of the soul as well, 
springs out of the depths of its own being. 

Page 119, note 1, line 2. After "Erdmann," add: Janet. 

Page 120, line 6, " Ex pro/es.so." Schaarschmidt says the term Ex 
professo is a technical expression occurring in classical literature (for 
example, Seneca and Quintilian) , which signifies : in a positive, precise 
way, in a pronounced or aforementioned manner. Leibnitz means to 
say, hitherto have we each set forth and justified his own speculative 
point of view (erkenntniss-theoretischen Standimnlct) ; now we come to 
the consideration of some classes of ideas in which we shall more than 
hitherto agree with each other. 

Page 120, note 1. After " Erdmann," add: Janet. 

Page 121, note 1. After " Erdmann's," add: Janet's. 

Page 122, lines 1, 2. "The membranes receive the sensation," etc. 
Of. Leibnitz's letter to Arnauld, April, 1687 (Gerhardt, Leibniz, philos. 
.Schrift., 2, 90, 91): "Les nerfs et les membranes sont des parties plus 
sensibles pour nous que les autres, et ce n'est peutestre que par elles que 
nous nous appercevons des autres, ce qui arrive apparemment, parceque 
les mouvemens des nerfs ou des liqueurs y appartenantes imitent mieux 
les impressions et les confondent moins, or les expressions plus distinctes 
de l'ame repondent aux impressions plus distinctes du corps. Ce n'est 
pas que les nerfs agissent sur l'ame, a parler metaphysiquement, mais 
c'est que l'un represente l'estat de l'autre spontanea relatione,''' 1 i.e. "The 
nerves and the membranes are the parts more sensitive for us than the 
others, and it is perhaps only by them that we perceive the others, which 
happens apparently, because the movements of the nerves or of the fluids 
belonging thereto imitate better the impressions and confuse them less, 
now the more distinct impressions of the soul correspond to the more 
distinct impressions of the body. Not that the nerves act upon the 
soul, to speak metaphysically, but that the one represents the state of 
the other by reason of a spontaneous relation.'''' Modern psychological 
investigation and experiment prove that the end-organs rather than the 
nerves "receive the sensation," or, in modern phrase, 'are acted upon 
directly by the stimulus,' the character of the sensation depending upon 
the peculiar structure of these different end-organs, and not upon the 
nerves. The formerly held doctrine of the " specific energy of the 
nerves" as being the cause of specific sensations, or as 'accounting for 
the quality of the sensation' — a doctrine which, according to Schaar- 
schmidt in his note to the passage (Erlauterungen z. d. Neuen Abhand- 
lungen ii. d. menschlich. Verstand v. G-. W. Leibniz, Berlin, 1874, J. H. 
v. Kirchmann's Philos. SibliotheJc, Bd. 56, Erlauterung, 92, p. 27) con- 
tradicts Leibnitz's statement in the text, — is now given up. Leibnitz's 
statement, while partly true, is nevertheless incomplete. He is right in 
stating "that tastes make themselves known to some extent through the 



740 LEIBNITZ'S CRITIQUE OF LOCKE 

nose, by reason of the connection of these organs," — modern experiments 
having proved taste and smell to be interdependent in their action in sen- 
sation, — but wrong as to the assistance of the teeth in the transmission 
of sound, the teeth not being ordinarily concerned in the process. If by 
"membranes" Leibnitz meant "end-organs," his statement, with the 
exception of the part regarding the hearing, would be correct, and his 
theory exhibit a remarkable degree of insight and foresight and of ap- 
proximation to the modern view of the subject. But this interpretation 
of his language seems on the whole inadmissible, "membranes" with 
him signifying probably the skin and the muscles, so that, while we may 
not justly regard him as having attained the fulness and completeness of 
the modern Understanding of the sensation-process, we may yet justly 
attribute to him a measure of insight into, and foresight of, what through 
subsequent investigation and experiment has been proved to be its true 
nature. 

Page 122, Chap. IV., § 1, line 5, "Solidity." On Locke's idea of 
solidity, cf. Lasswitz, Gesch. d. Atomistik, 2, 505-508. 

Page 123, note 3. After " Erdmann," add: Janet. 

Page 124, lines 9, 10 from bottom, "The scholastic conception of the 
air." Cf. New Essays, Bk. L, chap. 1, § 18, Th., ante, p. 83, lines 11, 12. 
On "rarefaction and condensation," line 12 from bottom, cf. Lasswitz, 
Gesch. d. Atomistik, Vol. 1, passim. 

Page 125, last line of text and note 1, " Animant." Some time after 
the text and note were in type, I came upon Leibnitz's letter to Leuwen- 
hoek, " Sur l'Aimant," cf. Dutens, Leibnit. op. om., 2, Pt. II., 92-94. In 
the correspondence, in Latin, of Leibnitz with Des Bosses there is con- 
siderable allusion to the Magnet, cf. Gefhardt, Leibniz, philos. Schrift., 
2, 437 (Postscript to Letter of Leibnitz to Des Bosses, February 5, 1712), 
492-495, 497-498 (Leibnitz to Hartsoeker, April 29, 1715, in French), 
505, 513 (Response de Mr. Hartsoeker, in French). As from this corre- 
spondence it is evident that Leibnitz was occupied more or less with the 
study of the Magnet, it seems as if the reading of the text should be 
" aimant," and the translation accordingly "magnet," and thus the view 
expressed in the last sentence of note 1, ante, p. 125, is confirmed. Janet 
also reads "aimant." Cf., also, a rough draft of letter of Leibnitz to 
Peter the Great, January 16, 1712, Foucher de Careil, (Euvres de Leibniz, 
7, 507, and a rough draft of a memorial of Leibnitz concerning the study 
of languages and the observation of the variation of the magnetic needle 
in the Russian Empire, ibid., 519, 531 sq. ; also, Observations ilber die 
Magnet-Nadel, ibid., 562 sq. 

Page 126, line 1, " Vacuum." That is, the effort of all bodies, particu- 
larly air and water, to fill up empty space. The doctrine of the universal 
attraction of all bodies has put an end to this false notion of " the fear of 
a vacuum " — horror vacui. On the vacuum, cf. Lasswitz, Gesch. d. Ato- 
mistik, passim. 



ADDITIONS AND CORRECTIONS 741 

Page 127, note 2. Add : Leibnitz's correspondence with Guerike, cf. 
Gerhardt, Leibniz, philos. Schrift., 1, 89-112. 

Page 129, line 1, " The view of the Cartesians." Janet, CEuvres philos. 
de Leibniz, 1, 95, note 1, refers to Descartes, Prin. Philos., II., § 4. 
Cf. Veitch's trans., pp. 233-234. 

Page 129, line 6, "Disagreement." Schaarschmidt remarks on this 
chapter as follows : "In this chapter on Solidity the antithesis of the 
Lockian and Leibnitzian view comes out with great acuteness. Locke, 
starting out from Sensualism, affirms that solidity is the most real property 
of bodies, a statement which, if logically developed, must lead to the as- 
sumption of hard impenetrable atoms. On the other hand, Leibnitz rightly 
maintains that all the properties of the body which Locke derives from 
solidity may be won without the assumption of a space-filling and im- 
penetrable first being, and that ' solidity ... is conceivable by pure 
reason, although the senses furnish the reason with the means of proof 
thereto.' " He also compares, on the atoms, Leibnitz's Nouveau systeme 
de la nature, § 11 sq. 

Page 129, last line, "Demonstration." This view of Leibnitz, as 
developed by Christian Wolf, became the seed from which sprang the 
Kantian doctrine of the categories. 

Page 130, line 13 [Chap. 7, line 6], "Idea of existence." Schaar- 
schmidt says : " The validity of this protest is clear, although Sensualism 
until the present time has not allowed itself to be brought back from the 
Lockian view. The concept of existence springs from the source of self- 
consciousness, not from the sensitivity. Sense-perception is as such first 
possible, after we have won the concept of existence from self-conscious- 
ness, and now after the analogy of our own being have placed it under 
the sense-phenomena for their explanation." 

Page 130, note 1. Add: Schaarschmidt translates: " Inbetracht- 
nahme des Daseins." t 

Page 136, note 1. Add : Dr. E. G. Robinson, President of Brown 
University, and Professor of Philosophy, 1872-1889, gave in his MS. 
Lectures to his classes on Psychology the following account of Con- 
sciousness : 

Consciousness 

" As this is the one controlling source of all our knowledge of mind, it 
is indispensable that we determine as precisely as we can just what we 
understand by it. 

" It is manifest at the outset that consciousness is the invariable accom- 
paniment and necessary condition of all actual knowledge and of every 
cognitive act. It is itself never an act but always a state of mind without 
which mental acts are impossible and which itself is possible only through 



742 LEIBNITZ'S CRITIQUE OF LOCKE 

cognitive acts, and this is true whatever the acts of cognition may be, 
whether relating to objects in the external world, to the bodily organism, 
or to strictly subjective thought and feeling. 

"It is evident, therefore, that we cannot with Reid regard conscious- 
ness as a faculty. A faculty can be called into exercise, consciousness 
cannot be, but always exists as a condition of the exercise of a faculty. 
Neither can we regard it as an intuitive idea, a regulative notion. An 
intuitive idea can exist only in consciousness. If consciousness be an 
intuitive idea, it must itself exist as the condition of its own existence. 
Neither can we regard it as identical with feeling, as sundry sensational- 
ists do, since feeling can exist only in consciousness. Nor yet again can 
we with Sir William Hamilton regard consciousness as the genus of 
which cognitive acts are the species, as the complement of the cognitive 
faculties. 1 A genus can exist only as made up of species. The distinc- 
tion between consciousness and cognition is, according to their definition 
when analyzed, only verbal and not real. Consciousness can be neither 
a special faculty, nor an intuitive idea, nor a distinct species of knowl- 
edge, nor the complement of the cognitive faculties, but is that within 
which all ideas must exist, any species of knowledge be acquired, and 
every faculty be exercised. 

"It cannot, accordingly, be correct to define consciousness as the soul's 
knowing that it knows, 1 or ' the power by which the soul knows its own 
acts and states,' 2 or the power to know that it is itself that knows. 3 
But consciousness is rather the souVs actual knowing with itself that it 
knows, that is, is that relation to itself into which the ego is brought by 
cognition of any object other than itself, is the ego as subject commun- 
ing with itself as object through the mediation of some object distinct 
from itself. It is not a power of the soul but is a state, 4 a condition, a 
function of the soul which always necessarily accompanies any normal 
or voluntary exercise of the soul's powers. Speaking figuratively and 
popularly, it is the mind's illumination of itself by its own action. 

"That the foregoing is a correct account of consciousness seems 
, evident : 

" 1. From the difference between cognition and consciousness and the 
relation of the one to the other. Cognition is a voluntary act of the ego, 
and consciousness is an involuntary state or condition of the ego which 
always accompanies its cognitions, and neither one can by any possibility 
exist without the other. Simple cognition is only a given correlation of 
subject and object ; whereas in consciousness, which must always accom- 

1 Sir William Hamilton, Metaph., 133 sq., 143 sq., Amer. ed. ; Discussions, 
p. 54, Amer. ed. 

2 President Noah Porter, Hum. Intellect, p. 83. 

3 President Mark Hopkins, Outline Study of Man, p. 107. 

4 In the oral exposition of this passage, Dr. Robinson remarked in substance 
as follows: "A 'state' is usually considered as something inert, stable, in- 
active ; but not so with Consciousness. Consciousness is an active state. 
' State ' is preferable to ' act,' as the latter implies volition. Consciousness is 
an involuntary state or condition of the ego." 



ADDITIONS AND COREECTIONS 743 

pany cognition, the knowing subject is in and by the cognitive act 
brought into correlation to itself as coexistent or conjunctive object. 

"2. The very word consciousness, which all are agreed in using, implies 
in its composition a partnership and an intercommunication between self 
as knowing subject and self as known object, an intercommunication 
which occurs momentarily and continuously in every cognitive act. 
Whatever may have- been the origin of the word, whether with philoso- 
phers or the unlettered, it etymologically vindicates the view of conscious- 
ness here given. 

"3. It is admitted on all hands that knowledge is impossible without 
consciousness. But if consciousness itself be a distinct kind of knowl- 
edge, whether generic or specific, then since all knowledge is possible 
only in consciousness, consciousness itself must have its conditioning 
consciousness and so on ad infinitum. But not only does the conscious- 
ness of every individual being have an absolute beginning, but every 
given instant of consciousness is as distinct and separate from the 
preceding as is every act of cognition from its preceding, and every 
given instant of consciousness is dependent on some given act of cogni- 
tion. Consciousness, therefore, is not an act of cognition, nor a power 
to cognize, but is the simple reflex action of the ego upon itself in its own 
acts of cognition ; and it cannot be the mind's power to know itself or to 
know that it is itself that knows, since it is a state or a relation of the ego 
to itself which is always dependent on the exercise of the power to know. 

"If what has been said be true, then it is evident that consciousness, 
although always inseparable from bodily sensation, is predicable only of 
mind as active intelligence or intellect. It is by the mind alone as the 
perceiving, thinking power of the soul that any of the soul's energies, 
cognitive, cogitative, emotive, volitional, can be brought into exercise or 
continued in action, and since it is only by the exercise of these energies 
that consciousness exists, it is of the mind alone, the perceiving and 
thinking power of the soul, that consciousness is predicable. Again, it 
also follows that there can be but one kind of consciousness, that it is 
always spontaneous, the invariable and necessary accompaniment of cog- 
nition, that is, it always accompanies cognition whether the cognition 
be of objects external or internal. It may vary in degree according to 
degrees of attention in acts of cognition, but it never changes from itself 
into consciousness of another kind. 

"The so-called self-consciousness or the reflective, acquired, philo- 
sophical consciousness, is nothing else than that act of mind by which 
the ego itself, its acts or states or its consciousness are .made objects of 
attention. This does not differ from any other act of cognition and 
knowledge. It furthermore, like every other act of knowledge, is always 
accompanied by a consciousness of the act, and the consciousness of our 
consciousness, when it is made an object of attention and knowledge, is 
just as clear as the consciousness we have when we perceive an external 
object or when we make a percept, a concept, or an inward emotion an 
object of attention and scrutiny." 



744 LEIBNITZ'S CRITIQUE OE LOCKE 



The Components of Consciousness and their Reality 

" When we make consciousness an object of attention and analyze it 
into its component parts, we find it always to consist of three distinguish- 
able elements, namely: the ego cognizing, the object cognized, and the 
communion of the ego with itself in the cognitive act ; that is, we find the 
soul communing with itself in the act of knowing something which is not 
itself. But these three elements, when themselves analyzed, reveal the 
existence of but two distinct quantities or entities, the ego and the object 
of its knowledge. Out of these two factors, subject and object, carefully 
analyzed, come directly or indirectly the entire materials of mental phi- 
losophy. 

" As to the real existence of these factors of consciousness, the subject 
and its objects, we may begin with the objects. If there be any doubt as 
to the reality of the mind's objects, the so-called subject-objects, whether 
they be sensations, feelings, perceptions, ideas, volitions, or whatever else 
simple or complex, there is still stronger reason for doubting the existence 
of an external world from which as cause or occasion these subject-objects 
have sprung, and reasons stronger still for doubting the existence of our 
doubt. If mental objects be unreal, doubt has no existence. The truth 
is, if there be any reality anywhere it is in the mind's own acts of subjec- 
tive cognition. 

"In like manner, if the object in consciousness has a real existence, 
still more indubitably real is the existence of the personal ego that knows 
the object in consciousness. This is evident in three ways : 

"Eirst. We are conscious only while one of our mental faculties or 
powers is in exercise. In the act of its exercise the ego immediately 
intuits itself as exercising its own energy. Self immediately cognizes 
self as active in every successive moment of consciousness. 

"Second. It is plain that the objects cognized on which the existence of 
consciousness is always dependent, even the most subjective and subtle of 
them, are clearly distinguishable from the ego that cognizes the object. 
In fact, no object in consciousness is ever cognized unless the cognizing 
self clearly distinguishes between itself and the object. Such discrimina- 
tion cannot take place unless the ego that makes it has an indubitably 
real existence. 

" Third. The existence of memory proves the real existence of the per- 
sonal ego. Consciousness is a succession of instants each of which is 
distinct from the preceding and following and each of which changes 
with the ever-changing objects of cognition and thought, and yet these 
vanishing instants so leave their traces on the personal ego that it can at 
will recall long series of them. Thus memory not only proves the exist- 
ence but the persistent identity of the ego that has an object of thought 
with its accompanying consciousness to-day which it can reproduce to- 
morrow, the next day, and with indefinite frequency thereafter. 

" Finally. The real existence of object and subject being indubitably 
established, it necessarily follows that the existence of consciousness, 



ADDITIONS AND CORRECTIONS 745 

within which both subject and object are found, and consequently its 
trustworthiness as a source of knowledge in Psychology, must be unhesi- 
tatingly admitted." (Lects. on Psychol., MS., §§ 12, 13, as given to the 
class of 1884.) 

Requisites and Difficulties in Consulting Consciousness 

" That is, in practising the so-called self -consciousness. 

"First. Requisites: It is necessary that there be close and concen- 
trated attention, patience and persistence in observation, frequent and 
varied observations, careful discrimination between different classes as 
well as between different species of the same class of mental phenomena ; 
that each particular phenomenon be analyzed and traced to its cause or 
causes ; that there be a distribution of phenomena according to their 
nature and causes so far as these can be ascertained. 

" But with the utmost care, attention, and discrimination in the anal- 
ysis and classification of the phenomena given in consciousness, there is 
a constant liability to error. The nature, relations, and causes of the 
phenomena to be observed are many of them so subtle and obscure that 
diversity and even conflict of view may be inevitable, but the disagree- 
ments, it must be remembered, turn chiefly on the theories respecting the 
origin of the phenomena and their relation to realities and not on the 
reality of the existence of the mental phenomena themselves. 

"Second. Difficulties: The observation and examination of the phe- 
nomena of consciousness, however, as compared with the observation 
and examination of phenomena in the external world, is attended with 
various, and to inexperienced minds with serious, difficulties. Thus : 

" («) So large a portion of early life is spent among and in the obser- 
vation of the phenomena of the outer world that it is difficult for many 
persons to acquire the habit of accurate observation of the subjective 
phenomena of mind. This difficulty is heightened : 

" (b) By the necessity the conscious subject is under of becoming the 
object of its own observation, the necessity of compelling himself to act 
and to observe himself at the same instant. Upon the phenomena of the 
outer world the mind can concentrate an undivided attention, but when 
the mind makes its own action an object of attention there is requisite 
the double effort to produce mental movement and to observe oneself 
in the process, the result beine at best but constrained and halting action 
of which from divided attention we can catch only hasty and imperfect 
views. 

" (c) Subjective acts and states occurring in rapid succession can be 
observed only instantaneously, while most objects of sense remaining 
comparatively permanent in form can generally be examined repeatedly 
and at leisure. The most evanescent of physical phenomena give ample 
time for observation in comparison with the most enduring phenomena of 
mind. 

" (e?) Every individual consciousness is isolated from that of every 



746 LEIBNITZ'S CRITIQUE OF LOCKE 

other, and the report of no one's consciousness, notwithstanding the 
unanimity in the deliverance of all consciousnesses, can be accepted or 
even understood by another without a personal scrutiny of his own; 
whereas in the natural sciences there may be many or few observers, and 
their reports can be understood and received without personal experiment. 

" (e) The objects of consciousness are many of them complex in them- 
selves and their causes and subtle in their relations to one another ; they 
therefore are much more difficult of observation and require much more 
careful discrimination in observing them than objects in the external 
world, the mechanical and chemical origin of which are at once and pal- 
pably discernible." (Lects. on Psychol., § 14, ed. of 1884.) 

To the above, as presenting more completely Dr. Bobinson's view of 
Consciousness, — a subject which "he regarded as fundamental to all 
order and rectitude of thought" in Psychology, and on which "he ex- 
pended much time and thought" in perfecting his conception and its 
statement, — may be added what he dictated to his classes on the question : 



" Can there be an Unconscious Modification op Mind ? 

" That is, can there be mental processes and the mind itself unaware of 
them ? The answer must manifestly depend on the meaning attached to 
the word mind. If by mind be meant the thinking personal essence, or if 
it denotes the co-ordinated psychical forces which constitute personal 
being, there can be no good ground for doubting that there may be 
unconscious modifications of both its states and its powers. There are 
depths in the potentialities of the personal being which consciousness 
never reaches. Consciousness knows nothing of the inner sources of 
energy whence thoughts, feelings, desires, and volitions emanate, but 
only of thoughts, feelings, desires, and volitions after they have taken 
form in the mind. It is upon the existence of these that consciousness 
depends, and of their existence alone can consciousness inform us. There 
may therefore be modifications of states of soul, increments and diminu- 
tions of intellectual and moral power, and losses of intellectual possessions 
of which we may be unconscious and of which we may remain uncon- 
scious till we learn them from unwonted phenomena. 

"So also thoughts and accompanying states of consciousness often 
spring from instinct and hereditary bias which have long lain latent and 
have existed and operated below consciousness. Instances of knowledge 
lost under some given condition of the brain and restored under other 
cerebral conditions are examples of the same kind of unconscious changes. 
Every species of mental action is more or less dependent on the state of 
the brain, but to ascribe these changes to unconscious cerebration is to 
assume that thought is the equivalent of physical force, is both the quan- 
titative and qualitative product of the brain alone, rather than the product 
of an active agent which uses the brain, and it is an assumption for which 
there is no sufficient ground. 

"But if by mind be meant the soul's acquisitive and cogitative powers, 



ADDITIONS AND CORRECTIONS 747 

the intellect, the intelligence, the question whether it may not be uncon- 
sciously modified is equivalent to the query whether there may not be #n 
unconscious mental act or (which is the same thing) an unconscious state 
of consciousness, a contradiction of terms. Every modification of mind, 
in the sense of the word mind here under consideration, must be by some 
mental act. But any mental act in order to be such must be a conscious 
mental act. Cognition and consciousness always coexist. An uncon- 
scious modification of mind would necessitate a mental act of which one 
was unconscious. 

" The facts often cited in proof of an unconscious modification of mind 
do not seem to warrant the conclusions drawn from them ; for instance, 
acts performed in obedience to any established habits, single but synthetic 
visions of complex objects, sudden and apparently unaccountable thoughts, 
sudden and mysterious recollection of long-forgotten persons and events, 
the apparently simultaneous carrying forward of several trains of 
thought. All these may be instances, not of unconscious cerebration or 
of unconscious modification of the mind, but of mental movements, the 
successive steps of which are too occult or too rapid and minute for the 
mind in the study of itself to follow. In compound and complex mental 
processes it is possible that simple steps may be so inadvertently taken as 
to be apparently taken unconsciously ; but an analysis of the process will 
show that while the degrees of consciousness may be indefinitely numer- 
ous, running down to the lowest stages of latent or sub-consciousness, 
yet unconsciousness is so far removed from ever so low a degree of con- 
sciousness as to be separated from it by an impassable chasm. As there 
are many degrees in life but none in death, so there are degrees in con- 
sciousness but none in unconsciousness." (Lects. on Psychol., § 20, ed. 
of 1884.) 

Page 138, note 1. Add : For the letter of Molyneux here referred 
to, dated March 2, 1693, cf. Locke's correspondence with Molyneux, in 
Locke's Works, 9, 34, 12th ed., London, 1824, 9 vols. 8vo. Berkeley, An 
Essay toward a New Theory of Vision, §§ 132, 133, Fraser's ed., Vol. 1, 
pp. 96, 97, refers to it ; also Locke, Philos. Wks., Bonn's ed., 1, 257-258, 
note t. On the relations of Locke and Molyneux, cf. Eraser, Locke, 
Blackwood's Philos. Classics, Edinburgh and Philadelphia, 1890, p. 234 sq., 
the letter referred to, p. 238. Molyneux died as a result of a journey, 
undertaken when ill, to see Locke. 

Page 139, lines 17-20, "In this case . . . united with that sense-knowl- 
edge with which touch has before furnished him." Cf. "The Mentor," 
a monthly, published by the Alumni Association of the Perkins Institu- 
tion for the Blind, Boston, Mass., U.S.A., Vol. 2, No. 3, March 1892, pp. 
81-86, " Sculpture by the sense of Touch," giving an account of a blind 
sculptor, Johnson M. Mundy, whose sight began to fail in his youth and 
slowly but surely grew less, until it practically vanished entirely. He 
learned the sculptor's art between the ages of 22 and 29, and practised it 
for twenty years till the loss of sight compelled him to give it up. Unable, 



748 LEIBNITZ'S CRITIQUE OF LOCKE 

however, long to endure " the monotony of an idle and useless existence " 
and " with unabated aspiration and fondness for his art," he resumed his 
work, performing the actual work of sculpture by the sense of touch. His 
last work up to the date of the article here referred to was a heroic statue 
of Washington Irving. 

Page 144, note 1. Add: Cf. Gerhardt, Leibniz, philos. Schrift., 6, 
522-528, letter 5 to Sophie Charlotte (" hitherto not published," Gerhardt, 
op. cit., 6, 477, note * — he should have said 'published entire,' as Foucher 
de Careil, Lettres et opuscules inedits de Leibniz, Paris, 1854, pp. 252-254, 
published a fragment of the same), in which Leibnitz subjects Bouhours' 
book to a sharp critique. Leibnitz also refers to Bouhours in his letter to 
Sebastian Kortholt, Sept. 30, 1708, Kortholt, Leibnit. Epistolae, 1, 282 ; 
Dutens, Leibnit. op. om., 5, 306-307 ; to Fried. Wilhelm Bierling, Oct. 24, 
1709, Kortholt, op. cit., 4, 8 ; Dutens, op. cit., 5, 355; Gerhardt, Leibniz, 
philos. Schrift., 7, 487: " Bouhursius mihi contemtu vindicandus, nee 
verbis a Germanis, sed rebus refellendus videbatur." Cf, also, Dutens, 
op. cit., 5, 190: "Mediocris vir fuit Bouhursius, qui neglecto religionis 
suee, cui se addixerat, habitu. Damaretum quendam effingere, et fcemi- 
neam elegantiam exprimere satagebat." 

Page 147, line 2 from bottom, " Modes." Cf. Descartes, Prin. Philos., 
Bk. I., § 56, ed. Cousin, 3, 98 ; Veitch's English trans., 217 ; German 
trans, by J. H. v. Kirchmann, 2d ed., Heidelberg, 1887 (Bd. 26 of his 
Philos. Bibliothek), p. 28- " Lorsque je dis ici facon ou mode, je 
n'entends rien que ce que je nomme ailleurs attribut ou quality. Mais 
lorsque je considere que la substance en est autrement disposed ou diver- 
sifiee, je me sers particulierement du nom de mode ou facon ; et lorsque, 
de cette disposition ou changement, elle peut etre appel6e telle, je nomme 
qualitds les diverses facons qui font qu'elle est ainsi nommfe ; enfin, 
lorsque je pense plus g6neralinent que ces modes ou qualit6s sont en la 
substance, dans les considerer autrement que comme les dependances de 
cette substance, je les nomme attributs. Et, parceque je ne dois conce- 
voir en Dieu aucune vari6t6 ni changement, je ne dis pas qu'il y ait en 
lui des modes ou des qualitfe, mais plutSt des attributs ; et meme dans 
les choses crepes, ce qui se trouve en elles toujours de meme sorte, comme 
1' existence et la dur^e en la chose qui existe et qui dure, je le nomme 
attribut, et non pas mode ou quality." Cf, also, New Essays, Bk. II., 
chap. 30, § 4, infra, p. 276, and note to p. 277, line 8, infra, p. 763. 

Page 147, note 1. Dele "Appendix, p. ." and substitute " Duncan, 

71-80." Cf, also, Neiv Essatjs, Bk. IV., chap. 10, § 7, Th., ad fin., infra, 
p. 505, §9, Th., p. 507. 

Page 149, line 15 from bottom, "The shortest great-arc of a circle." 
The French text is : "La longueur du plus petit grand-arc de cercle," etc. 

Page 150, line 13, "Buratini." Cf. Dutens, Leibnit. op. om., 6, Pt. I., 
319: " Gravuis, Anglus, in descriptione JEgypti apud Thevenot, Vol. 1, 
p. 14, mentionem facit, Titi Livii Buratini, jeune nomme Venitien fort 



ADDITIONS AND CORRECTIONS 749 

spirituel, qui £toit dans la conrpagnie. Thevenot in margine annotat : 
Buratini est maintenant maitre cle la monnoye du Roi de Pologne, et c'est 
de lui que l'on vit il y a dix ou douze ans un modelle d'une machine pour 
voler." 

Page 153, line 7, "Lessius." Leonard Lessius, 1554-1623, a Flemish 
Jesuit, was Professor of Philosophy at Douay, and of Theology, 1583-1623, 
at Louvain. He opposed the doctrine of grace of Thos. Aquinas, and was 
charged with favoring Semi-Pelagianisni. He was well acquainted with 
theology, law, mathematics, medicine, and history. For two of his 
Opera, cf. Migne, Theol. cur. compl., 3, 787 ; 15, 445. Janet, (Euvres 
philos. de Leibniz, 1, 120, note 1, states that he was a celebrated casuist, 
often cited in Pascal's Provinciales, and adds that of his ethical works 
the chief is the De justitia et jure (Migne, op. cit., 15, 445) ; and that of 
the theological works we have De perfectionibus moribusque divinis; De 
libertate arbitrii et prcescientia Dei ; De summo bono ; De Providentia 
numinis. 

Page 154, line 13, "Accidents or abstracts." The strong contrast 
between Locke's and Leibnitz's philosophies comes here again to the front. 
Locke regards substance as a mere creation of thought, a subjective expe- 
dient of the understanding which "invents" it as a unitary support to, 
or bearer of, the accidents. Leibnitz looks upon the " substance-concept 
as the suitable expression of the idea of the actual, to which we refer 
back the accidents. Every phenomenon as such, in his view, presupposes 
an actual being, since through such an actual being the phenomenon is 
first possible. Substance, accordingly, is in the case of all phenomena that 
which is constantly to be presupposed, the non-irrational (JYicht-nichtzu- 
denkende), but in no sense a mere auxiliary concept of only subjective 
validity." — Schaarschmidt. Leibnitz is in the direct line of Hegel in his 
emphasis of the concrete rather than the abstract. 

Page 154, line 4 from bottom, "Indefinite." Cf. Descartes, Prin. Philos., 
Pt. II., § 21, ed. Cousin, Vol. 3, p. 138: "Nous saurons aussi que ce 
monde, ou la matiere Vendue qui compose l'univers, n'a point de bornes, 
parceque, quelque part ou nous en voulions feindre, nous pouvons encore 
imaginer au-dela des espaces ind^finiment dtendus, que nous n'imaginons 
pas seulement, mais que nous concevons etre tels en effet que nous les 
imaginons ; de sorte qu'ils contiennent un corps ind^finement ^tendu," 
i.e. We know that this world, or the extended matter which composes the 
universe, has no limits because, should we wish anywhere to feign such 
limits, we can still imagine beyond spaces indefinitely extended, which we 
do not imagine only, but which we conceive to be in fact such as we imag- 
ine them, so that they contain an indefinitely extended body. 

Page 154, note 1, line 4. Instead of "Appendix," read: Duncan, pp. 
68-70 ; line 7, ditto, pp. 71-80 ; line 10, ditto, pp. 112-126. 

Page 155, line 26, "Motion." Cf. Leibnitz's 4th letter to Clarke, ad 
fin., Gerhardt, 7, 377; Erdmann, 758; Jacques, 2, 437 ; Janet, 2, 640 ; 



LEIBNITZ'S CRITIQUE OF LOCKE 



trans. Duncan, 253 ; 5th letter to Clarke, § 22, Gerhardt, 7, 394 ; Erd- 
mann, 765 ; Jacques, 2, 450 ; Janet, 2, 654 ; Duncan, 259. 

Page 156, note 1. Phys., VIII. [or H], 6, 258" 10: eirel 5e del dv-qaiv 
del dvai /cat fir] diaXelireiv, dudyKrj elval ri 6 irpwrov Kivel, etre ev dre irXeiou, 
/cat to irpuiTov klvovv d>dvr)TOv. 

Page 157, note 1. Add: $vo-lkt)s 'A/cpodtrews, A, 11, 219 b 1 : tovto yap 
icrnv 6 xP 0V °Si dpidpbs Kivqo~eu><i Kara, to irpOTepov koL WTepov. ovk dpa nlvrjais 
6 xP ovo s <* AA ' V dpidpbv e'xet i] /ctc^cris. Qvo-iktjs 'A/cpoduecos, A, 11, 219 b 8:65^ 
Xpbvos ecrTi to apid/Aov/j.evov /cat ou% <£ apLdp.ovp.ev. Cf. Zeller, Philos. d. 
Griech., 3d ed., 1879, II., 2 [Vol. 4], 402. ■ 

Page 158, note 1. Add : Spinoza regards all determination as a nega- 
tion ■ — Omnis determinatio est negatio — of this originally posited or 
necessarily presupposed absolute. Hegel likewise in his Logik maintains 
essentially the same position as Leibnitz, so that Leibnitz may rightly be 
said to be in the direct line of the philosophical development culminating 
in Hegel. Cf. Wallace, The Logic of Hegel, 1st ed., 1874 ; 2d ed., revised 
and augmented, Oxford, Clarendon Press, 1892-1894, passim. 

Page 160, line 9, "Transcendent." Janet, CEtivres philos. de Leibniz, 
1, 128, in his note to this passage, says: "Expressions of the scholastic 
mathematical language, rarely employed to-day. The surd (le sourd) is 
the incommensurable, for example, V2 ; le rompu — the broken — is the 
fraction, as J ; the transcendent is that which cannot be calculated by a 
limited number of arithmetical operations, for example, log 3. These 
three terms are comprised between two whole numbers." 

Page 162, note 1. Add: Locke's Essay, ed. Fraser, 1, 295, line 9 from 
bottom. 

Page 162, note 2. Add: Cf. the note of Foucher de Careil, Sur les 
trois sens du mot infini dans la philosophic de Leibniz, Nouvelles Lettres 
et Opuscules inedits de Leibniz, Paris, 1857, pp. 404-407 ; also A. Penjon, 
De infinito apud Leibnitium, Paris, 1878. 

Page 162, note 3. Add: Locke's Essay, ed. Fraser, 1, 277, line 14. 

Page 166, note 1. Add : Locke's Essay, ed. Fraser, 1, 300, line 10. 

Page 167, note 1. Add: The definition referred to runs as follows: 
" A mare autem sive diligere est felicitate alterius delectari, vel quod 
eodem redit, felicitatem alienam adsciscere [Erdmann — asciscere] in 
suam. Unde difficilis nodus solvitur, magni etiam in Theologia momenti, 
quomodo amor non mercenarius detur, qui sit a spe rnetuque et omni 
utilitatis respectu separates : scilicet quorum utilitas [Erdmann — felici- 
tas] delectat, eorum felicitas nostram ingreditur, nam quae delectant per 
se expetuntur." Cf. Dutens, Leibnit. op. om., 4, Pt. IV., 295 ; Erdmann, 
118, b. The entire preface to the Codex juris is given in Dutens, op. cit., 
4, Pt. III., 287-328. 



ADDITIONS AND CORRECTIONS 751 

Page 168, note 1, ad fin. Add : Infra, pp. 177 sq., 188. Also, Theo- 
dicee, III., § 404, Gerhardt, 6, 357; Erdmann, 620; Jacques, 2, 300; 
Janet, 2, 402. Cf., also, J. H. v. Kirchmann, Erlduterungen zur Th'eo- 
dicee 'von Leibniz (Bd. 80, of his Philos. Bibliothek, Leipzig, 1879), 
Erlauterung, 264, pp. 145-147. 

Page 172, line 4 from bottom, "Displeasure." Schaarschmidt says 
that neither Locke nor Leibnitz have yet reached the distinction between 
emotion and passion, as appears from the language of both ; aud that 
Kant first grasped the distinction and attempted to determine it more 
accurately. 

Page 174, note 1. Add: Phys., T, 201 a 10: i) rod dwdfiei optos evre- 
Xe'xeia, 77 tolovtov, kIv7]<tU ecmv, olov rod p,kv dXXotajroO, rj dWoitorov, dXXotwcm, 
tuu 5e av^rjTOu /cat rod dvn.Keip.ivov cpdirov (ovdev yap 6vo/j.a kolvov e7r' dp.(poiv) 
av^r](TLS /cat cpdlo-LS rod 8e yev-rjTou /cat (pdaprov yiveiris /cat <pdopa, tov 8e (poprjroD 
(popd. Metapliys., K, 1065 b 16: ttjv rod 8vvdp.ei fj toiovt6v eariv evipyeiav 
\tyu Kiv-nciv. Gf. Zeller, Philos. d. Griech., II., 2 [Vol. 4], 351 sq., 
389 sq. ; Wallace, Outlines of the Philos. of Aristotle, § 42, p. 77, 3d ed. , 
1883. 

Page 174, note 2. Add : Translations of the two pieces last referred 
to will be found in the Appendix, infra, the Bettage to the letter to Fabri, 
pp. 699 sq. ; the Specimen Dynamicum, pp. 670 sq. 

Page 175, line 5, "Idea of power." Leibnitz carefully distinguishes 
between mere power and force ("Macht" and "Kraft"). Cf. Be 
primoe. philos. emendatione, etc., Gerhardt, 4, 469; Erdmann, 122; 
Jacques, 1, 453 [in French] ; Janet, 2, 525 [in French]; Duncan, Philos. 
Whs. of Leibnitz, 69. 

Page 175, line 18, "Because of our ignorance." That is, we are thus 
far incapable of resolving our sense-impressions, i.e. the simple sense- 
qualities, into anything more simple, and are therefore compelled to 
regard them as simple presentations, although in themselves possibly 
composite and in fact in many cases in indirect ways shown to be so. 
Gf, also, New Essays, Bk. III., chap. 3, § 18, Th., infra, p. 317, and 
note 2. 

Page 175, line 24, "Primitive truths." Gf. New Essays, Bk. I., chap. 
1, and Bk. IV., chap. 2, infra, pp. 404 sq. 

Page 176, line 13 from bottom, "Casati." Paolo Casati, 1617-1707, 
a learned Italian Jesuit, who taught mathematics and theology at Rome, 
and was said to have converted Queen Christiana, of Sweden, to the 
Catholic faith. On his return from Sweden he became Director of the 
University of Parma. Among his works are Vacuum proscriptum, 
Genoa, 1649 ; Be terra machinio mota, Rome, 1668 ; Mechanicorum lib. 
VIII., Lyons, 1684 ; Be igne dissertationes physicce, Venice, 1686, 1695; 
Hydrostaticce dissert., 1695 ; Opticas, dissert., 1705. Lasswitz, Gesch. d. 
Atomistik, 2, 490, says: " Im Einzelnen ebenfalls durchaus korpuskular 



752 LEIBNITZ'S CRITIQUE OF LOCKE 



sincl die physikalisclien Erklarungen des Jesuiten Paolo Casati . . . Aber 
seine allgemeiue Auffassung der Natur ist dabei vollstandig scholast- 
isch." 

Page 176, note 1. Add: Cf Lasswitz, Gesch. d. Atomistik, 2, 421-428, 
especially 423-424. Malebranche changed his views under the influence 
of Huygens and Leibnitz. The Loix generates de la communication des 
mouvements, Lasswitz says, was added as an Appendix to the later edi- 
tions of the Becherche de la verite. 

Page 180, note 1. Add: Cf. § 13 of this chapter, infra, pp. 182-184, 
New Essays, Bk. IV., chap. 6, ad fin., infra, p. 462, note 1 ; also, Ger- 
hardt, 7, 108-111 ; Erdmann, 669 ; also the fragment entitled De Libertate, 
published by Foucher de Careil, Nouvelles Lettres et Opuscules inedits de 
Leibniz, Paris, 1857, pp. 178-185. "Apart from the freedom of fact and 
of right," says Schaarschmidt, "Leibnitz distinguishes between ethical 
freedom and free-will ( Willlcur). The former, ethical freedom, is the 
power to follow the ethical insight in spite of opposing internal hin- 
drances, such as the passions. This concept also is clear and simple. 
The difficulty proper lies hidden in the conception of free-will (tier 
Willliur), the liberum arbitrium, by which, as Leibnitz expresses him- 
self, is meant, 'that the strongest reasons or impressions which the 
understanding presents to the will do not prevent the act of the will from 
being contingent, and do not give it an absolute and, so to speak, meta- 
physical necessity.' " Leibnitz regards the action of the will as a motive 
which inclines, but does not compel, — but at the same time he assumes, 
Theodicee, Pt. I., § 52, a self-determination of the will over against which 
the expression incline appears as a mere evasion. Cf. infra, p. 462, note 
1. On Leibnitz's doctrine of the Will and Freedom, cf. G. Class, Die 
metaphys. Voraussetzungen d. Leibnitzisch Determinismus, Tubingen, 1874, 
pp. 9, 78 sq. ; F. Kirchner, Leibniz's Psychologie, Cothen, 1875, pp. 82 sq. ; 
M. Penzler, Die Monadenlehre u. Hire Beziehung z. griech. Philos., 
Minden, 1878, p. 23 ; L. Braeutigam, Leibniz und Herbart uber die Frei- 
heit des menschl. Willens, Heidelberg, 1882, pp. 3-17, 28-39 ; M. Nour- 
risson, La Philosophic de Leibniz, Paris, 1860, pp. 268-286 ; Kuno Fischer, 
Gesch. d. n. Philos., Vol. 2 [Leibniz] pp. 512-533, 3d ed. Heidelberg, 
1889. For a clear analysis and able, though brief, discussion of the vari- 
ous senses in which the "freedom of will " is used, and of " determinism," 
cf Robinson, Principles and Practice of Morality, pp. 122-137. 

Page 180, note 2. After " 1881," add : pp. 68 sq. The Greek text of 
the passages referred to reads thus: 'Hduca, N£/a>/xdx«a, T, 4, 1112 a 15: r; 
yap Tpoaipeais fiera \6yov Kai diavotas. 5, 1112 a 30 : /3ouAei/6/xe#a 5e irepl twv 
icp' ripuv vpaKTCiv. Cf., also, Sir Alexander Grant, The Ethics of Aristotle, 
3d ed., London, 1874, Vol. 2, pp. 17, 19, 'H0. Nik., III., chap. 2, § 17; chap. 
3, § 7. Peter's translation follows the chapter and section numbering of 
Grant's text. Cf, also, the following pasages from the so-called 'RdiKa 
Mey d\a — Magna Moralia — " which," Schaarschmidt says, " at least for 
Leibnitz, was a genuine work of Aristotle," — though now regarded, ac- 






ADDITIONS AND CORRECTIONS 763 

cording to Zeller, as "a sketch compiled from both " the Nicomachean and 
Eudemian ethics, "but more especially from the Eudemian " (Philos. d. 
Griech., II., 2 [Vol. 4], 102, note 1 ; Outlines of the Hist, of Greek Philos., 
New York, 1886, p. 175) : A, 16, 1188 b 25 : eirel 8e rb eKovcriov ev ovSepiig, 
bp/nrj early, \oiirbv hv eir\ to eK Siavolas yiyvopievov. 1188 b 31 : ws tov eKovcriov 
'6vtos ev rip oiavorjdrjvai. 1188 b 37 : evravda dpa rb eKovcriov irlirrei eh to fxera 
8iavolas. A, 17, 1189 a 31 : el toIvvv 77 irpoalpecris Spells tls j3ov\evr iktj fierd 
diavolas, ovk ecrri to eKovcriov irpoaiper6v. eKbvres yap iroWa irpdrropiev irpb 
tov 8iavoij9rjvai Kal (5ov\evcracrdai, olov Ka6l£op,ev Kal aviardp.eda Kal d\\a iroWd 
ToiavTa e/ccWes p.ev avev 8e tov Siavo-qdijvai, rb 8e Kara irpoalpecriv irav ijv p.erd 
diavolas. ovk dpa Tb eKovcriov wpoaiperuv, dXXd rb irpoaiperbv eKovcriov dv ri 
yap irpoaipih/.ieda wpdrreiv (3ov\evcrdpt,evoi, eKovres irpdrropiev. With this last 
passage, cf. 'H0. Nik., T, 4, llll b 6: rj irpoalpecris Srj eKovcriov piev cpalverai, 
011 TavTov Se, dXX' eirl ir\iov to eKovcriov. 1112 a 14 : eKovcriov fiev 8rj (palverai 
[17 irpoalpecris'], to 8' eKovcriov ov irav irpoaiperbv. 1113 a 9 : ovtos Se rod irpoai- 
perov j3ovkeVTOV opeKrov rCiv ecf>' ijfuv, Kal rj irpoalpecris av eit) f3ov\evTiK7] 6pe£is 
tQiv eft fifuv. The 'B.9. Nik., T, 3, llll a 22, defines rb eKovcriov, the vol- 
untary, — das Frehoillige, — thus: rb eKovcriov Sb&iev dv ehai ov r\ apxy ev 
avrcp elobri ra Kad' eKacrra ev ols r) irpd^is. 'B.6. ~EvSr)p.ia, B, 8, 1224 a 6 : 
\elirerai ev ru> 8iavovp.ev6v ircos irpdrreiv eivac rb eKovcriov. B, 9, 1225 a 36 : 
e7ret Se tovt' e%et ri\os, Kal ovre tt) opi^ei ovre ry irpoaipe'crei rb eKovcriov topicr- 
rai, \oiirbv 8r) bplcracrdai ra Kara 8idvoiav. B, 10, 1226 b 6 : r) yap irpoalpecris 
a'ipecris p.iv ecrriv, ov% dirXQs 84, dXX' eripov irpb ertpov • rovro Se ovx oUv 
re dvev ffKexpeios Kal j3ov~kijs. 81b 4k So^tjs j3ov\evT iktjs ecrriv r\ irpoalpecris. Cf, 
also, Zeller, Philos. d. Griech., 3d ed., II., 2 [Vol. 4], 587 sq. 

On Aristotle's doctrine of the Will and Freedom, cf. 'H6>. Nik., V. 1-8, 
1109-1115; Grant, Ethics of Aristotle, 2, 5-32, and notes; also his Plan 
of Book III., ibid., hi., iv., and Essay V., 1, 284 sq. ; Essay VII., 1, 376 sq. ; 
J. A. Stewart, Notes on the Nicomachean Ethics of Aristotle, Oxford, 
Clarendon Press, 1892, Vol. 1, pp. 224-230, 232-236, 240, 243-245, 250, 
279 ; Vol. 2, pp. 16, 17, 379, 380 ; Trendelenburg, Histor. Beitrdge z. 
Philos., 2, 149 sq. ; Windelband-Tufts, Hist, of Philos., § 16, 2, pp. 191, 
192. 

On Leibnitz's relations and indebtedness to Aristotle, cf. D. Jacoby, 
De Leibnitii Studiis Aristotelicis, Berlin, 1867 ; D. Nolen, Quid Leib- 
nizius Aristoteli debuerit, Paris, 1875 : M. Penzler, Die Monadenlehre u. 
ihre Beziehung z. griech. Philosophic, Minden, 1878, p. 29. 

Page 183, line 13 from bottom, "The best." Cf. New Essays, Bk. 
IV., chap. 6, ad fin., infra, p. 462, note 1. 

Page 184, lines 7, 6 from bottom, "A freedom of equilibrium absolutely 
imaginary and impracticable." Leibnitz argues against indeterminism 
and equilibrium of will, cf. Gerhardt, 7, 109: " Libertas indifferentice est 
impossibilis. Adeo ut ne in Deum quidem cadat, nam determinatus ille 
est ad optimum efficiendum. Et creaturse semper ex rationibus intends 
externisque determinantur " (ib., 110, in French); Erdmann, 669 (in 
Latin). Cf. Robinson, Principles and Practice of Morality, p. 126. 
3c 



754 LEIBNITZ'S CRITIQUE OF LOCKE 

Page 185, line 20, "Vigor of Will" Of. Robinson, Principles and 
Practice of Morality, p. 138, where Virtue is defined as "the soul's or the 
will's persistency of compliance, — its energy in complying with the moral 
law, " — a definition perhaps suggested by that of Kant, quoted in the 
foot-note: "the strength of the human will in the performance of duty." 

Page 185, note 1. After "Erdmann," add: Janet. 

Page 192, line 8, "Clearly felt." Schaarschmidt says: "Our feelings 
can be very lively, while the ideas causing them may be obscure, con- 
fused, nay even senseless (let one think, for example, of religious fanati- 
cism, of drunkenness, the aberrations of revenge, etc.) ; on the other hand, 
our thoughts can be. distinctly, i.e. from one another, indeed be distin- 
guishable, without being clearly, i.e. in their own content, conceived." 

Page 192, note 2. Add : The passage from the EtMca referred to in 
this note is found in Vol. 1, pp. 270 sq. of this edition. Cf. also the 
Short Essay on God, etc., Korte Verhandeling van God, etc., Bk. II., 
chaps. 5 and 19, ed. Van Vloten and Land, 2, 310, 338 ; Schaarschmidt' s 
German trans., pp. 54, 84 sq., in J. H. v. Kirchmann's Philos. Bibliothek, 
Bd. 18, 2ded., Berlin, 1874. 

Page 193, line 6, "Francisco Borgia." General of the Jesuits, 1565- 
1572. 

Page 199, note 1. Add: The texts of Erdmann, Jacques, and Janet, 
and the translation of Schaarschmidt end at "pleasure." 



Page 203, note 2. The note should read as follows : Gerhardt 
" Ou venons au propos ; " the phrase is wanting in the texts of Erdmann, 
Jacques, Janet, and in Schaarschmidt's translation. 

Page 204, note 1. After "proposer," the note should read: wanting 
in the texts of Erdmann, Jacques, Janet, and in Schaarschmidt's trans- 
lation. 

Page 204, note 2. After "gauche," the note should read: wanting in 
the texts of Erdmann, Jacques, Janet, and in Schaarschmidt's transla- 
tion. For the allusion, etc. 

Page 205, note 1. After " Erdmann," add: Janet. 

Page 205, note 2. After "Erdmann," add: Janet. 

Page 206, line 12 from bottom, "Following the good." Leibnitz is a 
forerunner of Kant in the expression here used that the chief end of 
reason is practical. "In Kant's view," says Schaarschmidt, "theo- 
retical reason has only the negative significance of raising us above the 
contemplation of nature and the sphere of experience to that position 
where beyond the sensuous the practical principles, by means of a legis- 
lation derived from freedom, unconditionally determine the will." Cf. 
also Leibnitz's definition in the same sense of " wisdom as the science of 



ADDITIONS AND CORRECTIONS 755 

happiness," Gerhardt, Leibniz, philos. Schrift., 7, 86; Erdmann, 671: 
" Weisheit ist nichts anders als die Wissenschaft der Gliickseeligkeit, so 
uns nehmlich zur Gliickseeligkeit zu gelangen lehret." 

Page 208, line 21, " Endure forever." Cf. Spinoza, Korte Verhandeling 
van God, Bk. II., chap. 26, ed. Vloten and Land, 2, 359 ; Schaarschmidt's 
trans. 105 : "Zo konnen wy 't met reden voor een groote ongerijmtheid 
achten, 't geene veele, en die men anders voor groote god-geleerde acht, 
zeggen ; namelijk, byaldien op de liefde Gods geen eeuwig leeven en 
kwam te volgen, zy als dan haar zelfs best zouden zoeken ; even als of zy 
iets dat beter was, als God, zouden uytvinden. Dit is alzo onnozel als of 
een vis wonde zeggen (voor welke doch buyten het water geen leven is) : 
by aldien my op dit leven in het water geen eeuwig leven en zoude 
komen te volgen, zo wil ik uyt het water na het land toe ; ja maar wat 
konnen ons die God niet en kennen dog anders zeggen ? " i.e. " Thus 
we can rightly pronounce exceedingly absurd the statement which many, 
whom we otherwise deem great theologians, make ; namely, that if eternal 
life did not follow from the love of God, then man should seek his own 
best good, as though man thereby could find something better than God. 
This were just as foolish as if a fish [for whom out of the water there is 
no life] should say, if for me after this life in the water no eternal life 
follows, I will go out of the water on to the land. What else, how- 
ever, can they who do not know God say to us ? " Schaarschmidt thinks 
that Leibnitz's accord with Spinoza was perhaps mediated by the Stoic 
doctrine. 

Page 208, line 25, "Absolutely indispensable." Cf. infra, p. 261, note 
2. Leibnitz, while admitting the truth of the Aristotelian and Stoic view, 
nevertheless contests that in this life we cannot always demonstrate the 
identity of the virtuous and useful, and supports the life of duty and 
overcomes the dualism between duty and pleasure through the "thought 
of God and immortality." Kant grounded rational belief in immortality 
upon this very dualism. 

Page 210, note 1. After "Erdmann" add: Janet. 

Page 210, note 2. Add : Eraser, Locke's Essay, 1, 858, reads : § 66. 
His edition gives full account of all the various readings and changes in 
the various editions of Locke's Essay, including those in the translation 
of Coste. It is in all respects the best edition of the Essay yet issued, 
and the thanks of all students of philosophy are most heartily rendered 
to Prof. Fraser for his splendid work. 

Page 211, note 1. Add : 3d ed., enlarged, 2 vols., 8vo, A. & C. Black, 
Edinburgh, 1893. 

Page 212, line 25, "Turn them aside from it." Cf. New Essays, Bk. 
II., chap. 27, § 36, Th. ; ante, pp. 194 sq., § 53, Th., 207. Perfectibility is 
Leibnitz's ethical norm, and the "luminous pleasures" are those which 
assist us in our efforts to attain this perfection, because they spring out 



750 LEIBNITZ'S CRITIQUE OF LOCKE 

of the need of, and therefore also out of the idea, though obscure, of the 
true good. 

Page 213, line 12, "Greatness of the consequent." Janet, CEuvres 
philos. de Leibniz, 1, 185, note 1, says : " The greatness of the conse- 
quence, i.e. the greater or less probability that the foreseen good or evil 
will occur; the greatness of the consequent, i.e. the greater or less good 
or evil which the outcome must bring." 

Page 213, note 1. After " Erdmann," add : Janet. 

Page 214, note 1, line 1. After " 70 a 3," add : t6 fxkv sIk6s etrri 7rp6ra<m 
evdo^os • 6 yap a>s iiri to iro\ii '{<ra<Tiv ovtoj yivofiepov r/ p.77 ycvofievov r; ov 17 p.77 6v, 
tovt' eariv slkos, i.e. "The probable," etc. And in line 5, after " 1357 a 34," 
add: to fj,ev yap slk6s eariv &s iiri to tto\v yivbjj,evov, i.e. "For the proba- 
ble," etc. 

Page 217, line 2 from bottom, "World." "Because," as Schaar- 
schmidt says, "mathematics as the science of magnitude is applicable 
only to sensible things." 

Page 218, lines 18, 19, " The term thought in the same general way." 
" We exercise an inner activity," says Schaarsclnnidt, " either so that we 
produce perception-(phantasie-) images or (formulated — sprachgeformte) 
thought-images. The lower situated entelechies do the former, of the 
latter minds only are capable. We can, continues Leibnitz, in case of 
necessity designate both of these activities as thought. To-day we [the 
Germans] use ' Vorstellen ' as the most general expression to indicate 
the inner activity." 

Page 218, note 1. Add : Fraser's Locke's Essay, 1, 371, line 3. 

Page 219, line 26, "Comes from thought.]" Schaarsclnnidt says in 
his note to this passage : "These weighty expressions are the pure result 
of the fundamental thought, that every substance acts from an inner 
spontaneity. Passion thus has for the spirit only the significance of a 
confused and therefore imperfect activity, whose most pregnant expres- 
sion for the subject is pain ; for bodies, however, passion means an 
imparted or mediated activity, in connection with which it is to be con- 
sidered that, since bodies are mere phenomena, their changes are also 
only phenomenal, whose grounds must always be sought in the spontane- 
ous forces of simple substances (out of whose joint-existence — Zusam- 
mensein — ouT confused thought forms the corporeal mass)." Cf. New 
Essays, Bk. II., chap. 8, ante, p. 131, note 1. Schaarsclnnidt adds: 
"Activity in the absolute sense, however, is the transition to greater 
perfection and thence also accompanied with pleasure." 

Page 219, note 1. After " Jacques," add : and Janet. 

Page 220, line 2 from bottom, "Complete separation. " Schaarsclnnidt 
says in his note to the text at this point, "Separation arises from the 
Aristotelian concept x^pio-p-os. Xwpij'ew is the separation or loosing of the 



ADDITIONS AND CORRECTIONS 757 

purely spiritual from the material. After Descartes had again renewed 
the ancient Platonic-Aristotelian Dualism in another way, Spinoza and 
Leibnitz, each in his own way, again set up a monism, which the realistic 
tendency of Locke in another way and towards another goal also endeav- 
ored to attain." 

Page 220, note 1, line 2. After " Erdmann," add : Janet. 

Page 222, line 10 from bottom, " Old word." That is " chevauchier," 
"chevalchier," " chevaucher," " chevalcher," " cevaucier," all these dif- 
ferent forms occurring in the old writers. For examples, cf. Littrd, who 
gives the Provencal "cavalcar," "cavalguar," Italian "cavalcare," all 
derived from the Low-Latin " caballicare." " Chevaucher," says Littr6, 
is reserved for elevated style and especially for narrations regarding the 
Middle Age ; " aller a cheval" is the common and daily form of speech. 

Page 222, line 2 from bottom, "Seen." Schaarschmidt says: "That 
Locke here makes the formation of the mixed or compound modes pro- 
ceed from wider expeiience, to which he certainly adds ' invention ' — 
from a purpose — Leibnitz not only allows in a noteworthy fashion, but 
he also adds thereto as a further source the activity of the fancy. Locke 
undoubtedly understands by mixed modes something wholly different 
from that which is formed by means of dreams and fancies ; namely, 
abstractions from given compound relations, which, according to the 
measure of our interest, or at least of our attention, are formed and 
linguistically fixed." 

Page 223, note 1. Add : For Leibnitz on Mademoiselle de Scudery, in 
the "Monatlicher Auszug aus allerhand neu herausgegeben, nutzlichen 
und artigen Buchern," Dec, 1700, pp. 909, 910, and^Dec, 1701, IV., cf. 
Guhrauer, Leibnitz' 1 s Deutsche Schriften, 2, 414-420. Cf, also, Foucher 
de Careil, Lettres et opusmdes inedits de Leibniz, Paris, 1854, pp. 254- 
260 ; F. de Careil, (Euvres de Leibniz, 2d ed., Paris, 1809, 2, 515-517. 

Page 224, line 23, "Called causes in the schools." Cf. Appendix, 
infra, pp. 637, 672 sq., 699 sq., for Leibnitz's further exposition of the 
doctrine here set forth. In this place, "without allowing himself to 
enter upon a critique of Locke's exposition of the term primal cause, 
Leibnitz," says Schaarschmidt, "contents himself with ascribing to it a 
double signification, one of which goes back to the Aristotelian termi- 
nology ; the other indicates the end. At the same time, however, he 
mentions the fact that the primal cause may also be understood as the 
material ground of a thing. Critical investigation of this important con- 
ception first begins with Hume." 

Page 227, line 11, "Promoter." Ch^ruel, Dictionnaire des Institu- 
tions Franchises, sub voc, says : " Promoteur " : " Ecclfeiastique charge" 
du ministere public dans les officialites (voy. ce mot) [in that article it 
is explained that officiality = the court of a bishop or archbishop], dans 
les assemblies du clerge, dans les chambres sup^rieurs ecclesiastiques, en 
un mot dans tous les tribunaux ecclesiastiques. Les fonctions des pro- 



758 LEIBNITZ'S CRITIQUE OE LOCKE 

motenrs consistaient surtout a maintenir les droits, libertfe et immunity 
de l'Eglise ; a veiller a l'observation de la discipline ecclesiastique et a 
poursuivre les crimes et delits qui etaient de la competence des juges de 
l'Eglise. II y avait quelquefois dans les officiality un vice-promoteur ; il 
6tait, comme le promoteur, nomme' par l'eveque." 

In short, the promoteur was a sort of ecclesiastical district attorney, 
and he is here on the opposite side of the case from the young lawyer. 
When he calls the lawyer " doctor juris," the latter objects that he ought 
to call him " doctor juris utriusque," i.e., doctor of both civil and canon 
law, or in our phrase, doctor of laws, LL.D. To which the promoteur 
replies sarcastically. 

Page 227, note 2, line 3. After "Eucken," insert: Gesch. und Kritik 
der Grundbegriffe der Gegenwart, Leipzig, 1878, pp. 69-78 (Leibnitz, p. 
70) ; Die Grundbegriffe der Gegenwart historisch und kritisch entwiekelt, 
2te, vollig umgearbeitete Auflage, Leipzig, 1893, pp. 98-102 (Leibnitz, 
p. 98), but not so fully as in the 1st ed., the author stating in the Preface, 
that "the historical statements are strictly limited to that which appears 
immediately requisite to the understanding of the present time." Eng. 
trans, of 1st ed., The Fundamental Concepts, etc. At end of note, add : 
Schaarschmidt states Leibnitz's view thus : "Knowledge a priori means 
with Leibnitz, who with his predecessors in this matter attached himself 
to the Aristotelian conception of the irpdrepov tvi cpvvei, knowledge from 
the cause, and, accordingly, knowledge a posteriori means with him 
knowledge from the working or result, and therefore from external ex- 
perience resting upon the phenomenon of things." Kant's usage differs 
from that of Leibnitz. A priori knowledge is for Kant that which pro- 
ceeds from pure reason and not from experience ; while a posteriori 
knowledge comes only from external experience, not "from result and 
working in general." Cf., also, J. H. von Kirchmann's Erlauterung, 
No. 25, to the Theodicee, Bk. I., § 44 ; p. 34 of his Erlauterung en zur 
Theodicee v. Leibniz, Leipzig, 1879. 

Page 228, note 2. Cf. infra, pp. 399, note 3, 551, note 4. 

Page 229, note 2, line 1. After " II. and VI.," add : ed. Cousin, 1, 
246 sq., 322 sq. 

Page 230, note 1. After u Dioptrica, IV., 1 sg.," add: ed. Cousin, 5, 
34 sq. ; after "-Passiones Animce, I., 31 sg.," add: ed. Cousin, 4, 63 sq. ; 
after "Prin. Philos., IV, 189, 196, 197," add: ed. Cousin, 3, 500, 507, 
509. 

Page 230, note 1. Add: Cf, also, Cousin, CEuvres de Descartes, 8, 
200, where Descartes, in a letter (dated by the annotator 1640 — the 
letter in Bk. II. , No. 36, in ed. of 1666) to Meissonier, "m^decin de 
Lyon," says: " Mon opinion est que cette glande " ["la petite glande 
nomm^e conarion''''~\ " est le principal siege de l'ame, et le lieu oil se font 
toutes nos pens6es. La raison qui me donne cette cr^ance est que je ne 
trouve aucune partie en tout le cerveau, exceptd celle-la seule, qui ne soit 



ADDITIONS AND CORRECTIONS 






double," etc. In a letter to Mersenne, dated by the annotator April 1, 
1640, Cousin, GEuvres cle Descartes, 8, 215 sq. [ed. of 1666, Bk. II., Letter 
No. 38], Descartes makes substantially the same statement and gives the 
same reasons therefor, and adds : " Mais je crois que c'est toute le reste 
du cerveau qui sert le plus a la m^moire," etc. 

Page 233, line 4 from bottom, "The union of the soul and the body." 
Leibnitz was undoubtedly satisfied that his Pre-established Harmony 
satisfactorily explained the "union of the soul and the body," and for 
those who accept his philosophy it does. But those who look for another 
explanation, for example, in a real reciprocal action between the soul and 
certain substances of the body, find in Leibnitz's semi-spiritualistic inter- 
pretation of matter a clue or suggestion thereto. 

Page 235, end of chap. 24, "Comprising substances." Leibnitz, ac- 
cording to Schaarschmidt, means to say that, strictly understood, the 
collective ideas are not signs of substances, rather, indeed, are the single 
objects themselves substances, as, for example, the army, the herd, con- 
sist of substances. Yet the collective ideas serve to a certain extent indi- 
rectly to indicate substances. Leibnitz adds this concession here because 
in his system of monads he departs very widely from the customary con- 
ception of substance, and yet may not lose all touch with the linguistic 
usage. 

Page 235, line 6, 5 from bottom, " Essence of reason.' 1 '' That is, ens 
rationis, which actuality reaches only so far as it is a thought-image. 

Page 235, line 3 from bottom, "Comes from the supreme reason." 
"Relations, so Leibnitz will have us understand the matter," says Schaar- 
schmidt, "are in the first place products of our thought, for they are 
neither the expression of substances, nor of the determinations (Attribute, 
Modi) inhering in them, but the expression of our subjective conception 
of the relation of things to one another. But this human conception, 
although also subjective, is yet again grounded in the nature of things, in 
particular in the nature of the mind, and to this extent springs out of its 
own constitution, like the eternal truths. And the constitution of the 
mind, as the 'mirror of the universe,' corresponds again to reality in 
virtue of the pre-established harmony. The thoroughgoing parallelism of 
the inner with the outer occurrence gives consequently to the relations, 
according to Leibnitz, a certain real meaning. ' ' 

Page 239, note 1, line 4. Instead of "Z,e&e?i," read: Eine Biographic. 

Page 241, note 1. Add : Corpus Juris Civilis, 6th stereotyped ed., Vol. 1, 
p. 659, a ; Dir/esta, ed. Mommsen, Berlin, Weidmann, 1893. Schaarschmidt 
says it is "a definition springing from Stoicism," and compares Gop- 
pert, Ueber einheitliche, zusammengesetzte unci Gesammtsachen nach rom. 
Becht, pp. 7 sq., 20 sq., Halle, 1871. 

Page 242, line 4, " Soul." Leibnitz is right in placing the identity of 
man in the soul and its conservation, instead of in the "well-organized 



LEIBNITZ'S CRITIQUE OF LOCKE 



body," as Locke does. The relative unity of the bodily organism results 
from the absolute unity of the soul. 

Page 245, note 1. Cf. Fraser, Locke's Essay, 1, 448, note 3. This sec- 
tion is numbered § 11 in Fraser' s ed. 

Page 245, note 2. After " Erdmann," add : Janet. 

Page 246, note 1. After " Erdmann," add : Janet. 

Page 247, lines 7-9. " The self constitutes identity real and physical," 
etc. This sentence contains the gist of the whole discussion. " The self " 
or the ego which "constitutes identity real and physical" is "the pre- 
supposition of that consciousness of the subject of itself to which the 
conviction of its own reality attaches." Consciousness itself is an active 
though involuntary modification or state of this self or ego. "The phe- 
nomenon of self '" is the ego's actual consciousness of itself, as the subject 
of all its inner experience, and as the constant accompaniment of the 
same. The self is accordingly by Leibnitz regarded as a real entity, a 
substance, constituting in itself "real and physical identity" which is 
recognized as "personal " in consciousness. But it must be remembered 
that for Leibnitz substance is dynamic, its essence is action, and its real 
identity consists in the continuity and connection of its activity. When 
this activity becomes distinctly conscious or is brought into distinct con- 
sciousness, it constitutes moral and personal identity. 

Page 249, note 1. Add : Janet reads : " elant." 

Page 250, note 1. Add : Cf, also, The Immortality of the Soul, Bk. II., 
chaps. 13, 14 ; Philos. Writings, ed. in 1 vol., London, 1662, pp. 116-121 
(each treatise paged separately in this ed.). 

Page 251, lines 12, 13, "Indifferent to every sort of matter." Janet, 
(Euvres philos. de Leibniz, 1, 224, in his note to this passage, says: 
" Aristotle believed also that the soul is not indifferent to every kind of 
matter, and avails himself of the fact to combat the doctrine of metemp- 
sychosis." Cf. Hepl tyvxys, Bk. I., chap. 5, Berlin Academy ed., 409 a 
31-411" 30 ; ed. E. Wallace, Cambridge, 1882, pp. 44-57. 

Page 251, note 1. After "Gerhardt," add: Janet. 

Page 251, note 2. After " Erdmann," add : Janet. 

Page 252, line 6 from bottom, "Two persons." On double and alter- 
nate personality, cf James, Psychology, 1, 379-392. 

Page 252, note 1. Add: Fraser's Locke's Essay, 1, 460, line 8. 

Page 252, note 2. Add: Fraser's Locke's Essay, 1, 461, line 6. 
" Sober" = " sane." 

Page 254, note 1. After " Erdmann," add : Janet. 

Page 254, note 2. After "Erdmann," add: Janet. 



ADDITIONS AND CORRECTIONS 761 

Page 256, lines 17-20. "For since there is an individual diversity," 
etc. Cf. Neio Essays, Bk. II., chap. 27, § 3, Th., ante, p. 239, and note 1 ; 
Bk. III., chap. 6, § 8, Th., infra, pp. 331, and 332, note 1. All true or 
actual difference is individual difference, consisting in some internal dif- 
ferentiating principle specifying the existence in this or that definite way, 
even though it first reveals itself only in " the course of time." With this 
thought is closely connected that of identity, on which cf. ante, p. 247, 
and note to lines 7-9, ante, p. 760. 

Page 257, note 1. After "Erdmann," add: Janet. 

Page 258, line 10, " Magnitude which I call imperfect." An imperfect 
magnitude is one which, because of its infinite minuteness, admits of no 
measurement. 

Page 259, note 1. After "Erdmann," add: Janet. 
Page 259, note 3. After " Erdmann," add : Janet. 

Page 261, note 1. Add: Piinjer, G-esch. d. christlich. Religionsphi- 
losophie, Braunschweig, 1880, 1, 123, Eng. trans., Edinburgh, 1887, 1, 
165, in his account of the controversy of Vedelius and Joh. Musaeus {cf. 
ante, p. 587, notes, 1, 2), gives, from Musseus, another use of the term. 
Piinjer says : "1st aber die philosophische Pramisse allgemein, die theo- 
logische partikular, dann muss sorgfaltig untersucht werden, ob die 
betreffenden philosophischen Principien nothwendig und allgemein gel- 
ten (absolute et simpliciter necessaria) oder nur fur ein besonderes 
Gebiet, bedingungsioei.se (secundum quid et physice)" ; i.e. "But if the 
philosophical premiss is universal and the theological premiss is particular, 
then it must be carefully examined whether the philosophical principle in 
question is necessarily and universally, valid (absolute et simpliciter neces- 
saria), or applies only to a particular sphere and conditionally (secundum 
quid q% physice)." [Italics are mine. — Tr.] 

Page 261, note 2. Add : Cf. New Essays, Bk. II., chap. 21, § 55, ante, 
p. 208, and note to p. 208, line 25, ante, p. 755. 

Page 262, note 1. Add: Leibnitz, Observationes de Principio Juris, 
§ 13 (Dutens, Leibnit. op. om., 4, Pt. III., 273), says : " Deum esse omnis 
naturalis juris auctorem (quod ait § 41) verissimum est, at non voluntate, 
sed ipsa essentia sua, qua ratione etiam auctor est veritatis," etc. 

Page 262, note 2. Add: Cf, also, Dr. Robinson's Lecture, "Moral 
Law in its relations to Physical Science and to Popular Religion," in 
Boston Monday Lectures — Christ and Modern Thought — 1880-1881, 
pp. 31-59. 

Page 263, note 1. Add : Teubner, Leipzig, 1865. Vopiscus says of 
Bonosus : " Bibit, quantum hominum nemo. De hoc Aurelianus saepe 
dicebat: 'Non ut vivat natus est, sed ut bibat,' quem quidem diu in 
honore habuit causa militife. Nam siquando legati barbarorum unde- 
cumque gentium venissent ipsi propinabantur, ut eos inebriaret atque ab 



762 LEIBNITZ'S CRITIQUE OF LOCKE 



his per vinum cuncta cognosceret. Ipse ■ quantumlibet bibisset, semper 
securus et sobrius et, ut Onesimus dicit, scriptor vitse Probi, adhuc in 
vino prudentior." 

The reference in the next line, also taken from Vopiscus, ibid., is to 
Proculus, and not Bonosus, and the text should be corrected accordingly. 

Page 264, line 10, "Depends upon truth." I.e., as Schaarschmidt 
says, "upon the ever-equal reality of the ethical world-order." 

Page 267, note 1. After " Erdmann," add: Janet. 

Page 270, note 1. After "Erdmann," add: Janet. 

Page 273, note 1. After "Erdmann," add: Janet. 

Page 273. note 2. After "Erdmann," add: Janet. 

Page 274, note 1. After "Erdmann," add: Janet. After "§15," 
add : So also Fraser's Locke's Essay, 1, 493. 

Page 274, note 3. Add : Fraser's Locke's Essay, 1, 494, reads § 16. 

Page 275, note 1. After "Erdmann," add: Janet. Fraser's Locke's 
Essay, 1, 494, reads: "betwixt the 100,000th and the 1,000,000th part 
of it." 

Page 276, note 1. Add : Of. Gerhardt, Leibniz, philos. Schrift., 3, 225, 
where Leibnitz says: " II est encor a propos de considerer qu'il y a deux 
abus considerables dans les definitions, qu'on peut commettre en voulant 
former des idees: Pun est ce que 1' excellent Jungius (c/. Appendix, infra, 
p. 636, note 1), appelloit obreption, 1' autre est ce que j'appelle chimerisme, 
par exemple si quelqu'un raisonnoit ainsi : il m'est permis de combiner les 
id^es, et de donner un nom a ce qui en resulte ; prenons done l'id^e d'une 
substance ou il n'y ait rien que de l'etendue et appellons cela corps, done 
les corps qui sont dans la nature n'ont rien que de l'etendue, il y auroit a 
la Ms ces deux fautes clans ce raisonnement. E obreption y seroit en ce 
qu'ayant donne" au mot : corps, la definition qui bon me semble (ce qui 
est en quelque facon arbitraire), je veux par apres l'appliquer a ce que 
d'autres homines appellent corps. C'est comme si dans la Geometrie 
quelqu'un donnoit a ce mot : ovale, la definition que d'autres Geometres 
donnent a 1' Ellipse, et vouloit prouver par apres que les ovales de M. des 
Cartes sont des sections du cone. Le chimerisme est icy d'avoir fait une 
combinaison impossible, car on n'accorde point qu'il est possible qu'il y 
ait une substance qui n'ait que de l'etendue. Je scais que ces Messieurs 
veulent se justifier de l'obreption, en disant qu'on ne s§auroit concevoir 
autre chose dans les corps qui sont dans la nature, que ce qu'ils ont mis 
dans leur definition ; mais en cela ils commettent une fausse supposition, 
ou bien ils confondent concevoir et imaginer ; car il est bien vray qu'on ne 
sgauroit imaginer que ce qui est etendu, mais ils reconnoissent eux memes 
ailleurs qu'on concoit des choses qui ne sont pas imaginables. Ouy, 
diront ils, mais ce n'est que la pensde qu'on ne peut point imaginer. Je 
reponds, qu'en cela ils font encor une autre fausse supposition, en pre- 



ADDITIONS AND COEEECTIONS 763 

tendant que rien ne scauroit estre concu que pens6e et Vendue, oublians 
qu'ils parlent souvent eux memes de la force qui n'est pourtant ny l'un 
ny l'autre, outre qu'ils n'ont point prouve" qu'il n'y a rien de possible que 
ce que nous concevons." 

Page 277, line 8, "Capable of existing together." Leibnitz, in argu- 
ing against Locke's view of the passivity of the mind in relation to its 
"simple ideas" and its activity in their combination into "complex 
ideas," affirms that the mind "is active in reference to simple ideas," 
that the relations are objectively significant and valid through the deter- 
mination of the "supreme intelligence," that the mixed modes "may be 
real accidents," which do not become merely subjective from the fact 
that we perceive them by thought. According to Leibnitz, everything 
really possible is in a certain sense an actual object of intelligence : to 
the divine intelligence an actual, to the human intelligence a universally 
possible object. The external existence of this thought-object really adds 
nothing to the being of this object, and alters nothing in the relation of 
the thought to it. Cfi, also, New Essays, Bk. II., chap. 12, § 3, Ph., 
ante, p. 147, and note to line 2 from bottom, " modes," ante, p. 748. 

Page 277, note 1. Add: Fraser's Locke's Essay, 1, 500. In § 1, Locke 
has "Fantastical or chimerical," Eraser's ed., 1, 497; Bohn's ed., 1, 508. 

Page 277, note 2, line 1. After " 345 a 25," add : ol 8e irepl ' Ava&y6pav 
Kal At]ia6kpitov (pus eivai to ydXa Xeyovcnv aarpwv rivQsv ■ top yap ijXlov virb 
ttjv yrjv <pepbp.evov ovx bpav evia tCjv acrrpwv. 

Page 281, note 2. Add: The Greek text of the passages referred to 
in the note is as follows : Ilepl ^vxv^ r, 6, 430 a 26-30 : i\ p.ev o&v twv 
aSiaipe'ruv vbr}<ns ev tovtols, irepl a ovk eari to \pev8os • ev ols 8e Kal to \[/ev8os 
Kal to aXijdes, crvvdecris ris ^5tj vorjp.a,Twv ucnrep ei> ovtwv, Ka.da.izep '~E,/j.ire5oK\rjs 
e(prj " rj iroWuiv fxev KOpcrai dvatjxeves ej3\do-T7]o-av," eireiTa avvTldeadai. rrj (piXia. 

Hepl ''Epp.r/velas I., 16 a 12: ffrjp.e'iov 5' ecrTi rovde' Kal yap 6 Tpaye\a<pos 
o-q/jLaivei p.e"v ti, obirw 8e aXrjdes r/ \pev8os, edv p,rj to eivai r] /J.r] eivac irpoaTedrj, 
r) dirXSis ?) /cara xP 0V0V - Of., also, New Essays, Bk. III., chap. 3, infra, 
pp. 310-318, and the notes, especially pp. 310, note 2, 317, note 3. 

Page 281, line 17, "Possibility." Schaarschmidt states that Christian 
Wolf placed this definition of truth here given by Leibnitz at the head of 
his collected science. According to Wolf, Log. Disc, prcelectt., philoso- 
phy is the science of the possible so far as it can be. Ueberweg, Hist, of 
Philos., Eng. trans, by Morris, New York, 1871, Vol. 1, p. 4, gives it, 
Philos. Bationalis. Disc. Prcelim., §29: "philosophia est scientia possi- 
bilium, quatenus esse possunt." 

Page 281, note 1. After "Essays," add : Bk. III., chap. 3, § 15, Th., 
infra, pp. 315 sq., especially p. 317, note 3 ; after " chap. 5," add : ad fin., 
infra, p. 452, and note 1. 

Page 282, note 1. After "Erdmann," add: Janet. 

Page 282, note 2. After " Erdmann," add : Janet. 



764 LEIBNITZ'S CRITIQUE OF LOCKE 

Page 283, line 17, " Ottavio Pisani." An Italian jurist, who published 
in Italian his Lycurgus seu leges promptam justitiam promoventes ; trans- 
lated into German, and published, Sulzbach, 1666, 12mo. Leibnitz men- 
tions him in his Bedenken welchergestalt den Mdngeln des Justiz-Wesens 
in theoria abzuhelfen, cf. Guhrauer, Leibnitz's deutsche Schrift., 1, 257, 
also Beilagen, ibid., 42 ; Dutens, Leibnit. op. om., 4, Pt. 3, 230-234 (Latin 
trans, of the same, regarding which, cf. Guhrauer, op. cit., 1, 41 sq. — On 
p. 41, op. cit., line 9 from bottom, "220-24" should read: 230-234, as 
above cited, the present reading being a typographical error). 

Page 283, note 1. After " Erclmann," add : Janet. 

Page 284, line 17, " Inclinations." Schaarschmidt says that " in these 
remarks lies the germ of the recognition of the law of association, which " 
Johann Gebhard Ehrenreich Christian Maass, 1766-1823, Professor of 
Philosophy at Halle University, "further elaborated in his Versuch iiber 
die Einbildungskraft, Halle and Leipzig, 1797 ; afterwards J. F. Fries, 
1773-1843, in his Neue Kritik der Vermmft, 2d ed., 1828-1831, p. 148 sq., 
and which finally J. F. Herbart, 1776-1841, and his school have attempted 
more closely to investigate and establish." F. H. Bradley, The Princi- 
ples of Logic, pp. 279, 297, 312, 313, refers to a portion of Maass' discus- 
sion. Cf, also, Hamilton's Beicl, Notes D** and D***, 2, 882-917, espe- 
cially 890, 899, 913 sq. Maass followed Wolff's Psych. Emp., Frankfort 
and Leipzig, 1732, ed. Nova, 1738 ; but he may also have been influenced 
somewhat by Leibnitz, as the New Essays were published in 1765 by 
Raspe, and therefore accessible for nearly thirty years before his own 
work appeared. 

Page 284, note 1. After " Erclmann," add : Janet. 

Page 284, note 2. After/' Erdmann," add : Janet. 

Page 284, note 3. After "Erdmann," add : Janet. 

Page 284, note 4. After "Erdmann," add: Janet. 

Page 286, note 1. Add: Recently Mr. R. L. Garner has been investi- 
gating the language of monkeys, Avith the aid of the phonograph, and 
published an account of his investigations in an interesting book entitled 
The Speech of Monkeys, New York, Chas. L. Webster & Co., 1892. An 
unfavorable notice of the book appeared in "The Nation," October 6, 
1892, p. 267 b, the gist of which appears in the following sentence : " As 
a scientific record of original discoveries, it has little value." 

Page 288, note 1. Add : Cf New Essays, Bk. III., chap. 3, § 5, Th., 
infra, pp. 307, 308. Also, Hamilton, Metaphysics, Lect. XXXVL, pp. 
492 sq., Boston, 1875. 

Page 297, line 11, " Hypothesis," etc. Leibnitz's hypothesis has been 
wholly verified by modern philology. 

Page 297, note 1. Add : For an interesting account of Leibnitz's 
services to comparative philology, cf. Max Muller, Lects. on the Science 



ADDITIONS AND CORRECTIONS 765 

of Language, 2d ed., London, 1862, Lect. 4, pp. 131-135 ; New York, 
Chas. Scribner, 1862, pp. 135-139. Cf, also, Guhrauer, Leibnitz, Eine 
Biographie, 2, 126 sq. ; Toucher de Careil, (Euvres cle Leibniz, 7, 519 sq., 
a rough draft of a memorial of Leibnitz concerning the study of lan- 
guages ... in the Russian Empire. 

Page 298, note 1, line 3 from end. After "p. 409," insert: "Lites de 
Boehmianis sententiis inanes esse censeo, et Boehmium nee sibi, nedum 
aliis intellectum," i.e. etc. 

Page 300, note 3. After "Erdmann," add: Janet. 

Page 300, note 4. After " Erdmann," add : Janet. 

Page 300, note 5. After "Erdmann," add: Janet. 

Page 304, note 1, line 8. After "Dutens, op. cit., Vols.," add : 4, Pt. 
II. , p. 56 : Ab insigni apud Bremenses Theologo Gerhardo Meiero, qui 
(ut hoc obiter dicam) hortatu meo prseclarum opus aggressus est Glossarii 
Saxonici titulo, in quo origines Germanicarum vocum multas eruet illus- 
trabitque, nee pauca non pervulgata proferet in lucem." At end of note, 
add: Janet, (Euvres philos. de Leibniz, 1,274, note 3, gives the dates of 
Meier's birth and death, 1646-1680, and titles of his "principal philo- 
sophical works " : Compendium logicce divince; Aranearum telas divince 
existential testes; De dubitatione sceptica et cartesiana. 

Page 304, note 2. Add : The date of Schilter's death being 1705, and 
the mention of the same in the text as having "just" occurred, is evi- 
dence that Leibnitz at least briefly touched up this part of the New 
Essays as late as 1705. 

Page 308, line 10 from bottom. Read: Q-r cathead, instead of "large 
head ;" and line 8 from bottom, read : great, instead of "large." 

Page 308, line 3 from bottom. After "wormwood," insert: (absin- 
thium). 

Page 313, line 8, "Living rational being." Cf. Trendelenburg, Histor. 
Beitr. z. Philos. , 3, 53, 54. 

Page 316, note 1. After "(Bonn's ed.)," add : Fraser's Locke's Essay, 
2, 28. 

Page 317, note 1. Add : cf. New Essays, Bk. IV., chap. 4, § 5, Th., 
infra, p. 445, note 1. 

Page 317, note 2. Add : Cf, also, New Essays, Bk. II., chap. 21, § 3, 
Th., ante, p. 175, and note to p. 175, line 18, ante, p. 751. 

Page 317, note 3. Add: Cf, also, Prantl, Q-esch. d. Logik, Bd. 1, 
p. 516, note 33, where he refers to Cicero, Of., I., 2, 7; Fin., II., 2, 5; 
D. orat., I., 42, 189 : " est enim definitio earum rerum, quse sunt eius rei 
proprise quam definire volumus, brevis et circumscripta qusedam explica- 



766 LEIBNITZ'S CRITIQUE OF LOCKE 

tip"; II., 39, 164; III., 29, 113; Orat., 33, 166; Top. 5, 26; Quint., 
Inst., VII., 3, 15. 

Page 318, note 1. Add: Fraser's Locke's Essay, 2, 29. 

Page 319, note 2. Add : Erdmann, 443-445. 

Page 321, note 4. After "chap. 9, ad med.," add: " 'How can that 
be ? ' cried Don Quixote ; ' didst thou not tell me that thou sawest her 
winnowing wheat '? ' ' Take no heed of that, sir,' replied the squire ; ' for 
the fact is, her message, and the sight of her too, were both by hearsay, 
and I can no more tell who the lady Dulcinea is than I can buffet the 
moon.' " 

Page 322, note 1. Add : Aldrich, Artis logicce rudimenta, ed. H. L. 
Mansel, 3d ed., Oxford, 1856, pp. 30, 31 (diagram on p. 31). 

Page 323, note 1, line 3. After " Erdmann," add : Janet. 

Page 324, note 2. Add : Hypoth. phys. nova, § 57 ; Gerhardt, 4, 208. 
Cf, also, New JEssays, note to p. 47, lines 18, 19, ante, p. 726. 

Page 326, note 1. Add: Cf. note to p. 43, line 14, ante, p. 724. 
"Leibnitz," says Schaarschmidt, "makes here a weighty remark. All 
demonstration appeals only to the (real) possible and to that which in a 
logical way inferred from the same is so far thought-wise necessary ; 
reality or the actual, on the other hand, can be known only historically 
or empirically, not, however ^ philosophically." 

Page 326, note 2. Add : Janet, (Euvres philos. de Leibniz, 1, 293, 
agrees with the reading of Jacques. 

Page 329, note 1, line 2. After " 1888," add : Paris Academy ed., by 
C. M. Galisset, 7th ed., 1862, p. 140 ; Corpus Juris Civilis, Berlin, Weid- 
mann, 1893 (Inst, of Justinian, ed. by Paul Krueger), Vol. 1, p. 13 b; 
line 3, after " 1890," add: Collectio Librorum Juris Antejustiniani, ed. 
Krueger, Mommsen, and Studemund, Vol. 1, pp. 50, 51, 3d ed., Berlin, 
Weidmann, 1891; line 4, after "1870," add: Corpus Juris Civilis 
(Digest, ed. by Mommsen, and paged separately), Vol. 1, p. 112. At 
end of note, add: Rudolph Sohm, Institutes of Soman Law, trans, from 
4th German ed., by Jas. Cranford Ledlie, Oxford, Clarendon Press, 1892, 
pp. 258-268. 

Page 332, note 1. Add : For Hegel's interpretation of Leibnitz's prin- 
ciple of individuation, — prindpium individuationis, — (cf. New Essays, 
ante, p. 239, note 1) cf. Wallace, The Logic of Hegel, 2d ed., Oxford, 
Clarendon Press, 1892, pp. 217, 218. 

Page 333, note 1. Add: Fraser's Locke's Essay, 2, 68. 

Page 334, note 1. Add : On the natural order in the vegetable king- 
dom, Schaarschmidt cites J. H. Burckhardi, Epist. ad Leibnitium, Wolffen- 
biittel, 1703. Cf., also, Epist. G. Q-. Leibnitii ad A. Q. Gackenholtzium, 
M.D., de methodo Botanica, § 10 ; Dutens, Leibnit. op. om., 2, Pt. II., 173. 



ADDITIONS AND CORRECTIONS 767 

Page 335, note 1, line 1. After " 50," add : Eraser's Locke's Essay, 
2, 69. So also Coste's translation, p. 360, ed. Amsterdam, 1742, Vol. 3, 
p. 129, ed. in 4 vols., Amsterdam, 1774. 

Page 337, note 3. Add : A 5th ed., Hamburg, 1887. 

Page 343, note 1. Add: Also Gerhardt, Leibniz, math. Schrift., I., 2 
[Vol.2], 1-208, Briefweehsel zwischen Leibniz und Hugens van Zulicliem. 
Also an earlier ed. in Pt. II. of Christ. Hugenii aliorumque seculi XVLI. 
virorum celebrium exercitationes mathematical et philosojrfiicce. Ex manu- 
scriptis in bibliotheca Lugduno-Batavce servatis cdidit. P. I. Uylenbroek, 
Hagfe Comitum, 1833. On the relation of Gerhardt's ed. to that of Uylen- 
broek, cf. Gerhardt, op. cit., II., 2 [Vol. 2], 9, 10. Gerhardt says, p. 10 : 
"Es hatte mithin in jedem Ealle auf die Sammhmg Uylenbroek's Riick- 
sicht genommen werden mlissen, der die Leibnizischen Originale vor 
sich hatte." Cf, also, New Essays, note to p. 16, line 22, ante, p. 723. 

Page 344, note 4. Add : Professor Schaarschmidt having kindly sent 
me Ulrich's note, and Ulrich's translation being rare and generally inac- 
cessible, it is here given: " Dieser Knabe ward 1661 in einem Alter von 
neun Jahren in einem Walde von Litthauen von den Jaegern unter den 
Baren gefunden. Es war noch ein anderer Knabe bei ihm, der aber den 
Jaegern entwischte. Dieser wehrte sich als man ihn fangen wollte anf ang- 
lich init seinen Nageln und Zahnen ungemein tapfer, musste aber zuletzt 
der Gewalt nachgeben. Er war iibrigens wohl proportionirt, weiss, hatte 
blonde Haare und eine angenehme Gesichtsbildung ; man kommte ihn aber 
durch nichts bandigen, vielweniger zu Kleidung und menschlicher Nahr- 
ung gewohnen. Er erhielt in der Tauf e den Namen Joseph Ursinus. ' ' 

The story is of course fabulous, it being impossible during the winter 
to live in Poland without clothes, even were it anywise probable that 
bears would live with children without eating them." 

Page 349, note 1, line 3 from bottom. Dele "2d ed." — since, accord- 
ing to the author's " Avertissement," the work "is not a 2d ed." of his 
earlier work, entitled De la philosophic scholastique, 2 vols., Paris, 1850, 
but an entirely new and independent work. 

Page 353, line 5, " Prophetic vision." Leibnitz wrote a critical essay 
on the Story of Balaam, which is found in Dutens, Leibnit. op. am., 4, 
Pt. II., 275-278. Wilhelm Brambach has published a monograph, en- 
titled Gottfried Wilhelm Leibniz Verfasser der Histoire de Bileam, Leipzig, 
1887, in which he gives an account of the various arguments for and 
against its Leibnitzian authorship, maintains that Leibnitz was the author, 
and gives Leibnitz's approved text of the piece. 

Page 357, note 1. Add: Fraser's Locke's Essay, 2, 86. 

Page 359, note 1. Add : Fraser's Locke's Essay, 2, 88. 

Page 380, note 1. Add: On More, cf. Tulloch, Bational Theology 
and Christian Philosophy in England in the 17th Century, Edinburgh, 



LEIBNITZ'S CRITIQUE OF LOCKE 



Wm. Blackwood & Sons, 1872, 2, 303-409, the "ethereal vehicles," 396, 
the "spirit of nature," 397. 

Page 382, note 1. Add: Cf. New Essays, Bk. L, chap. 1, ante, p. 67, 
and note to p. 67, lines 3, 4, ante, p. 732. 

Page 382, note 2. Add: Cf. also, Dutens, Leibnit. op. om., 6, Pt. I., 
315, Leibnitiana, No. C, where Leibnitz says: " Henricus Moras statuit 
prreexistentiani animarnm, sive quod animse create fuerint cum mundo, 
quam sententiam Plato, Origines, aliique jampridem foverunt. Mea 
opinio est, omnia, ut sic dicani, plena esse animarum vel analogarum 
naturarum, et ne brutorum quidem animas interire." 

Page 386, note 1. Instead of "Jacques reads," read: Jacques and 
Janet read, etc. 

Page 387, note 1. Add: In the "Bulletin des Sciences Matkdma- 
tiques, 2d Series, Vol. 16, 1892, Pt. I., p. 18, in a review of C. Huygens, 
(Eavres completes, La Haye, 1888 sq., the following statement occurs : 
" La courbe a 2 y = x 2 (a — x) rentre dans la categoric general e des courbes 
a p+q-ryr = xf{a—x)i, qu'on appelle les perles de de Sluse. Elle est une 
cubique a centre (au point d'inflexion x=^a, ?/ = o)." Cf, also, the letters 
in this ed. of Huygens, Nos. 401, 403, 408, 419, 434, 436, referred to in 
this review. In letter 461, the review goes on to say : " il est question 
d'un rapport remarquable entre les deux perles a-y 2 = x s (a — x) et y^ = 
x n (a — x)." Cf, also, letter 435. 

Page 388, lines 23, 27, 32, " §§ 23, 23, 24." These sections are numbered, 
respectively, §§ 23, 24, 25, in Eraser's Locke's Essay, 2, 142-143 ; also in 
Locke, Philos. Works, Bohn's ed. 2, 108-109 ; and in Coste's French 
trans., Amsterdam, 1742, pp. 409, 410, 4 vols, ed., Amsterdam, 1774, 3, 
248, 249. 

Page 392, lines 6, 7. "The majority of the mixed modes nowhere exist 
together. ' ' The French text of all the editions is : "La pluspart des 
modes composes n' existent nulle part ensemble." The grammatical con- 
fusion of a singular subject and plural verb is probably occasioned by the 
too condensed summary of Locke's statement, i.e. "Another reason that 
makes the defining of mixed modes so necessary, especially of moral 
words, is what I mentioned a little before, viz. that it is the only way 
whereby the signification of the most of them can be known with cer- 
tainty. For the ideas they stand for, being for the most part such whose 
component parts nowhere exist together," etc. (Fraser's Locke's Essay, 
2, 158; Locke, Philos. Works, Bohn's ed., 2, 122); in Coste's trans., 
ed. 1742, p. 421, ed. 4 vols., 1774, 3, 276 : "Une autre raison qui 
rend la definition des Modes mixtes si n6cessaire, et sur-tout celle des 
mots qui appartiennent a la Morale, c'est ce que je viens de dire en pas- 
sant, que c'est la seule voie par oil Von puisse avoir certainement la sig- 
nification de la plupart de ces mots. Car la plus grande partie des id6es 
qu'ils signifient, dtant de telle nature qu'elles n' existent nulle part ensem- 
ble," etc. 



ADDITIONS AND CORRECTIONS 



Page 404, note 1. Add : For a specimen of Euclid reduced to syllo- 
gisms, extracted from the very curious and rare Analyses Geometrical of 
Herlinus and Dasypodius, cf. Aldrich, Artis Logical Pudimenta, ed. 
Mansel, Oxford, 1856, 3d ed., Appendix, note L, ad fin., pp. 264-266. 
Sir William Hamilton calls Herlinus and Dasypodius " zealous but thick- 
headed logicians," Aldrich, op. cit., p. 248, note r (Mansel). The 5th 
proposition of the 1st Bk. is also analyzed by Mill, Logic, Bk. II., chap. 
4, pp. 162, 163, 8th ed., New York, Harper and Bros., 1881. 

Page 405, note 1. After " Erdmann," add : Janet. 

Page 405, note 2. After "Erdmann," add: Janet. 

Page 408, note 1. Add : Eor a brief account of the Ramist- Aristotelian 
controversy, cf. Piinjer, (resell, d. Christlich. Religionsphilos., 1, 89-92 ; 
Eng. trans., Hist, of the Christian Philos. of Religion, 1, 118-123. 

Page 412, note 1. After "Erdmann," add: Janet. 

Page 414, note 1. After " Erdmann," add: Janet. 

Page 414, note 2. Add: Fraser, Locke's Essay, 2, 185. 

Page 425. At end of first paragraph of note continued from p. 424, 
after " 1, 187," add : letter to Coming, March 19, 1678, ibid., 1, 199 ; also 
the writing with "neither superscription nor place nor date," ibid., 4, 
274 sq., especially 277, 278. 

Pages 428, 429. " Certain theologians claim that the fire of hell burns 
up separated souls." Cf. New Essays, Preface, ante, p. 62, and note to 
line 10 from bottom, ante, p. 729, 730. 

Page 431, line 10 from bottom. " Et quidquid Schola finxit otiosa." 
I have not been able to find the author or source of the Latin line. 

Page 432, line 11, " Lignum nephriticum." A term used by the old 
pharmacologists, signifying a wood, supposed to be that of the horse- 
radish tree, which has been used in decoction for affections of the kid- 
neys, — Nephritic wood, from the Greek veeppbs, a kidney. 

Page 434, note 1. Line 2, after "1890)," add: Collectio Librorum 
Juris Antejustiniani, eel. Krueger, Mommsen and Studemund, Berlin, 
Weidmann, 1891, 1, 86; and line 6, after "1888)," add: Corpus Juris 
Civilis, Berlin, Weidmann, 1893, 1, 23 b. 

Page 445, note 1. Add : On the history and significance of the terms cpav- 
rao-ia, (pdvra.(xij.a, "phantasma," cf. Siebeck, Gesch. d. Psychologie, Gotha, 
1880, 1884, passim. Leibnitz in his letter to Thomasius, Feb. 16, 1666, 
Gerhardt, Leibniz, philos. Schrift., 1,8, says: " Omnis color est impressio 
in sensorium, non qualitas quaedam in rebus, sed extrinseca denominatio, 
seu ut Th. Hobbes appellat, phantasma." On Hobbes' use of the term, 
cf. his Works, and Lange, Hist, of Materialism, 2d ed., 1, 288-289. For 
Thomas Aquinas' use of the term, cf. Ueberweg, Hist, of Philos., New 
York, 1875, 1, 449. 
3d 



770 LEIBNITZ'S CRITIQUE OF LOCKE 

Page 447, note 1. Add: Eraser, Locke's Essay, 2, 237-239, and cf: 
ibid., 2, 73, note 3: "An idiot, 'Such men do chaungelings call, so 
chaunged by faries' theft.' Spenser, Faerie Queen, Bk. I., canto X.; 
also Shakespeare, Midsummer Night's Dream, ii., I., 21." 

Page 450, note 1, line 4 from bottom. After " pp. 312-314," add : also, 
G. Croom Robertson, Philos. Bemains, Williams & Norgate, 1894, pp. 

274-278. 

Page 462, note 1. Add : Cf. " Leibnitz and Protestant Theology, " by 
Professor John Watson, of Queen's University, Kingston, Canada, in 
"The New World," March, 1896, Vol. 5, pp. 112-122. Cf, also, New 
Essays, Bk. IV., chap. 7, § 11, Th. (2), infra, p. 474, and note 1 ; chap. 
17, § 23, Th. (2), infra, p. 579, and note 1. 

Page 464, line 6, "The number of the axioms." Mansel, in the Appen- 
dix to his ed. of Aldrich, Artis Logical Budimenta, 3d ed., Oxford, 1856, 
p. 258, says: "The numerous attempts of Geometers to diminish or get 
rid of their axioms have been steps in a wrong direction. The number 
of axioms, instead of being diminished, should be very considerably in- 
creased ; and the errors that have hitherto prevailed on the nature and 
foundation of Geometrical reasoning have been mainly owing to the man- 
ner in which many indispensable assumptions have been either omitted 
altogether, or concealed among the definitions." 

Page 465, note 1. Add : Cf. also addition to this note, ante, p. 768. 

Page 474, note 1. Add: Cf. Neio Essays, Bk. IV., chap. 6, ad fin., 
ante, p. 462, note 1, and addition thereto above ; chap. 17, § 23, Th. (2), 
infra, p. 579, and note 1, and addition thereto, infra, p. 773. Dieckhoff, 
Leibnitz Stellung zur Offenbarung, Rostock, 1888. 

Page 481, note 1. Add: For Aristotle on the "middle term," cf 
Wallace, Outlines of the Philos. of Aristotle, 3d ed., 1883, §§ 23, 24, 
especially the latter, and the passage of Aristotle there quoted. For the 
history of the term, cf. Prantl, Gesch. d. Logik. 

Page 482, lines 1-3. The text should read: "Made him reject alto- 
gether their use in the establishment of the truth, and goes as far as to 
make them a party to confusion [of ideas] in conversation." 

Page 483, note 1. After "Princip. Philos., II., §§ 1, 4, 11," add: 
ed. Cousin, 3, 120, 123, 129. 

Page 484, note 1, line 2. After " §§ 16 sg.," add : ed. Cousin, 3, 133 sq. 

Page 486, note 1. Add: Corpus Juris Civilis {Digest ed. Mommsen, 
and paged separately), Berlin, 1893, 1, 718 b. 

Page 486, note 2. Line 3, after "locupletiorem," add: Corpus Juris 
Civilis, Berlin, 1893, 1, 873b; after "Tit. VI., 14," add: ibid., 1, 169b; 
line 6, after "lucrum," add: ibid., 1, 300a; after "§ 4, ad fin.," add: 1, 



ADDITIONS AND CORRECTIONS 



Page 487, note 1. After " Tit. XVII., 1," add : Corpus Juris Civilis, 
Berlin, 1893, 1, 868 a. 

Page 487, note 2. Line 2, after "1888), 1 ' add: Collectio Librorum 
Juris Antejustiniani, Berlin, Weidmann, 1893 (Inst. ed. Krueger), 1, 
47 b ; at end of note, add : ed. 1893, 1, 120 a, 593 a. 

Page 487, note 4. At end, add : On Sennert, cf. Lasswitz, Gesch. d. 
AtomistiJc, 1, 436-454. 

Page 492, note 3. Line 4, after "24, ad fin.'" add: ed. Mommsen, 
1893, 599b; line 6, after "ib., 26," add: ib., 599b; line 7, after "55," 
add: ib., 869b; line 8, after " ib., 129," add: ib., 871b. 

Page 495, note 1. Add: Cf, also, the quotation from the Theodicee, 
P. II., § 184, infra, p. 635, note 2, ad fin. 

Page 495, note 2. Add: Cf., also, Leibnitz's letter to Conring (with- 
out place or date ; probably written at the beginning of 1670 — Gerhardt's 
note), Gerhardt, Leibniz, philos. Schrift., 1, 160: Ego suppono cum 
Carneade (et Hobbius consentit) Justitiam sine utilitate propria (sive 
prasente sive futura) summam esse stultitiam longe enim absunt ab 
humana natura Stoicorum et SadducEeorum de virtute propter se colenda 
superbse jactationes. Ergo omne justum debet esse privatim utile, sed 
cum Justitise forma consistat in publica utilitate, sequitur quod non pos- 
sit accurate demonstrari hsec propositio : homo prudens debit semper agere 
quod justum est, nisi demonstretur esse quendam perpetuum vindicem 
publicise utilitatis (nam aliorum oculi metusque non ultra ligabunt pru- 
dentem, quam quousque juvare aut nocere possunt) id est Deum, cumque 
sensu manifestum sit, eum non esse semper vindicem in hac vita, super- 
esse aliam, id est esse aliquem Deum, et humanam animam esse immor- 
talem.' n 

Page 496, line 7 of note continued from p. 495. After " 1877," add: 
J. L. Lincoln, "Marcus Aurelius Antoninus," in In Memoriam John 
Larkin Lincoln, 1817-1891, pp. 484-502, Boston, Houghton, Mifflin & 
Co., 1894. 

"Page 506, note 1. After "Bonn's ed.," add: Eraser, Locke's Essay, 
2, 315. Coste's translation of Locke's Essay, ed. 1742, p. 519, 4 vol. ed., 
1774, 4, 131, reads: "finis." 

Page 510, note 1. Add: The note here referred to (cf, also, Coste's 
translation of Locke's Essay, ed. 1742, p. 523, note 2, 4 vol. ed. 1774, 4, 
141, note 2 ; translation of a part of the note, Fraser Locke's Essay, 2, 
321, note 2), reads thus: " Ici M. Locke excite notre curiosity, sans 
vouloir la satisfaire. Bien des gens s'dtant imagines qu'il m'avoit com- 
munique' cette maniere d'expliquer la creation de la matiere, me pridrent 
peu de terns apres que ma traduction eut vu le jour, de leur en faire part ; 
mais je fus oblige de leur avouer que M. Locke m'en avoit fait un secret 
a moi-meme. Enfin long-terns apres sa mort, M. le Chevalier Newton, a 



772 LEIBNITZ'S CRITIQUE OF LOCKE 

qui je parlai par hazard de cet endroit du livre de M. Locke, me decouvrit 
tout le mystere. Souriant, il me dit d'abord que c'etoit lui-mgme qui 
avoit imagine cette inaniere d'expliquer la creation de la matiere, que la 
pens^e lui en etoit venue daus 1' esprit un jour qu'il vint a tomber sur 
cette question avec M. Locke et un seigneur Anglois [Le feu Comte de 
Pembroke, mort au mois de Fevrier de la presente ann£e, 1738]. Et voici 
comment il leur expliqua sa pens^e. ' On pourroit,' dit il, ' se former en 
quelque maniere une idee de la creation de la matiere en supposant que 
Dieu eut ernpeche par sa puissance que rien ne put entrer dans une 
certaine portion de l'espace pur, qui de sa nature est penetrable, kernel, 
ne"cessaire, infini ; car des-la cette portion d'espace auroit l'impdn^tra- 
bilite, Tune des quality essentielles a, la matiere : et comme l'espace pur- 
est absolument uniforme, on n'a qu'a supposer que Dieu auroit com- 
munique' cette espece d'impen6trabilit6 a une autre pareille portion de 
l'espace, et cela nous donneroit, en quelque sorte, une idee de la mobility 
de la matiere, autre quality qui lui est aussi tres-essentielle.' Nous voila 
maintenant deiivres de l'embarras de chercher ce que M. Locke avoit 
trouv6 bon de cacher a ses lecteurs : car c'est la tout ce qui lui a donne 
occasion de nous dire, ' Que si nous voulions donner 1' effort a notre esprit, 
nous pourrions concevoir, quoique d'une maniere imparfaite, comment 
la matiere pourroit d'abord avoir ete produite,' etc. Pour moi, s'il m'est 
permis de dire librement ma pensee, je ne vois pas comment ces deux 
suppositions peuvent contribuer a nous f aire concevoir la creation de la 
matiere. A mon sens, elles n'y contribuent non plus qu'un pont contri- 
bue a rendre l'eau qui coule immediatement dessous, impenetrable a un 
boulet de canon, qui venant a tomber perpendiculairement d'une hauteur 
de vingt ou trente toises sur ce pont y est arrete" sans pouvoir passer a 
travers pour entrer dans l'eau qui coule directement dessous. Car dans 
ce cas-la, l'eau reste liquide et penetrable a ce boulet, quoique la solidite 
du pont ernpeche que le boulet ne tombe dans l'eau. De meme, la puis- 
sance de Dieu peut empecher que rien n'entre dans une certaine por- 
tion d'espace, mais elle ne change point par-la la nature de cette portion 
d'espace, qui restant toujours penetrable, comme toute autre portion d'es- 
pace, n'acquiert point en consequence de cet obstacle, le moindre degre 
de l'impenetrabilite qui est essentielle a la matiere," etc. 

Fraser, Locke's Essay, 2, 321, 322, note 2, above referred to, states that 
"the idea of the creation of matter which Locke had in view in this 
curious passage has occasioned various conjectures," and he refers to 
that of Leibnitz in this passage, to Reid's in Intell. Powers, Essay II. , 
10 [ed. Hamilton, 8th ed., 1880, 1, 287 a], and to Dugald Stewart, Essay 
II. , chap. 1, p. 63. Reid thinks Locke agrees with Berkeley; Stewart 
is almost tempted to think that Locke's idea of matter is "somewhat 
analogous to that of Boscovich." Fraser says that "this 'dim concep- 
tion,' if it means that the material world may be resolved into a con- 
stant manifestation of God's power to man's senses, conditioned by 
space, so far coincides with Berkeley's account of it ; he emphasises the 
sensuous manifestation of divine power in selected spaces, as well as 



ADDITIONS AND CORRECTIONS 773 

the ultimate dependence of space on sense. Newton, it seems, suggested 
that 'creation of matter' means, God "causing in sentient beings the 
sense-perception of resistance, in an otherwise pure space, — a theory- 
akin to Berkeleyism hi its recognition of the Supreme Power, and to 
Boscovich in its conception of the effect." 

Page 513. At end of note, add: translation, Appendix, infra, p. 
717 sq. 

Page 522, note 1. After "Gerhardt," add: Janet. 

Page 534, note 1. Line 1, after "Tit. VII., 1," add: Collectio Li- 
brorum Juris Antejustiniani, ed. Krueger, Mcanmsen and Studemund, 
Berlin, Weidmann, 1878, 2, 52; line 5, after "Tit. I., 33," add: Corpus 
Juris Civilis {Digest, ed. Mommsen), Berlin, 1893, 1, 667 b. 

Page 534, note 2. Add: ed. Mommsen, 1893, 1, 665a. 

Page 534, note 3. Add : ed. Cousin, 1, 148. 

Page 545, note 2. Add : New ed. of Bolsec, Vie de Calvin, by P. L. 
Chastel, Lyons, 1875. 

Page 548, note 3. Add : Fraser, Lockers Essay, 2, 379. 

Page 552, note 1. Add: Cf., also, note to New Essays, Preface, ante, 
p. 51, lines 11-13, infra, p. 727 ; also, New Essays, Bk. IV., chap. 20, 
§ 11, Th., infra, p. 613, and note 1. 

Page 567, note 1, line 3. After "296," add: Bonn's ed.; Fraser, 
Locke's Essay, 2, 403-405. 

Pages 575, 576, note 1. Add : The doctrine set forth in the note is 
closely allied to the inner light of the Quaker theology. Cf. Neiv Essays, 
Bk. IV., chap. 19, infra, p. 599, and note 1 ; also, Bancroft, Hist, of the 
United States, Centenary ed., 1876, Vol. 2, pp. 87-92. 

Page 579, note 1. Add : Cf. New Essays, Bk. IV., chap. 6, ad fin., 
ante, p. 462, note 1 ; 7, § 11, Th. (2), ante, p. 474, note 1 ; also, on the 
general philosophical question, "The Roots of Agnosticism," by Pro- 
fessor James Seth, in "The New World," September, 1884, Vol. 3, pp. 
458-471 ; and on the special problem here under discussion, "Leibnitz 
and Protestant Theology," by Professor John Watson, in "The New 
World," March, 1896, Vol. 5, pp. 102-122. Professor Watson's state- 
ment and criticism of Leibnitz's doctrine is admirable. He holds that 
Leibnitz's distinction of two kinds of truth, truths of reason and truths of 
fact, cannot be maintained, that "for a Being of infinite knowledge the 
possible and the actual are coincident," that " the only possible reality is 
that which is capable of being actualized," that there can be no choice 
between hypothetical worlds, and that the existing world is the only pos- 
sible one, and is "necessary just because it is the expression of an abso- 
lute reason." 



774 LEIBNITZ'S CRITIQUE OF LOCKE 

Page 581, note 1. At end, add : Further references on the whole 
subject: Lange, Gesch. d. Mater ialismus, 2d ed., 1, 182 sq ; Eng. trans., 
1, 218 sq. ; E. Renan, Averroes et V Averroisme, Paris, 1852 ; 3d ed., Paris, 
1869. 

Page 585, line 6, " Motives of credibility." Cf. New Essays, Bk. IV., 
chaps. 16, § 14, Th., ante, p. 554; 17, § 23, Th. (2), ante, p. 579, and 
note 1. Cf., also, Dutens, Leibnit. op. om., 1, 680, where Leibnitz says : 
"Motifs de croyance ou de credibility (comme ils les appellent) c'est-a- 
dire, outre les raisons explicables de n6tre Foi, qui ne sont qu'un amas 
d'argumens de diff^rens degres de force, et qui ne peuvent fonder tous 
ensemble qu'une foi humaine, ils demandent une lumiere de la grace du 
Ciel, qui fasse une entiere conviction, et forme ce qu'on appelle la Foi 
divine," i.e. " Motives of belief or of credibility (as they call them), that 
is to say, besides the explicable reasons of our faith, which are only a 
mass of arguments of different degrees of force, and which all together 
can establish only a human faith, they demand a light of the grace of 
heaven, which produces a complete conviction, and forms what is called 
the divine faith." 

Page 588, lines 16-19. " What is only necessary by a physical neces- 
sity (i.e. founded upon induction from that which is customary in nature, 
or upon natural laws which, so to speak, are of divine institution)," etc. 
Cf. ante, p. 261, note 1, and addition thereto, ante, p. 761. 

Page 606, note concluded from p. 605. Line 10, after "April 20-30, 
1669, G. 1, 27," add: Appendix, infra, 650; line 20, after "p. 33," add: 
translation, Appendix, infra, 631-651. 

Page 613, note 1. Line 1, after " p. 51, line 11," add : and note thereto, 
infra, p. 727 ; line 2, after " §§ 52, 90," add : ed. Cousin, 3, 217, 256; 
line 5, after " § 48 sq.," add: ibid., 3, 214 sq. 

Page 634, line 24, "Gilbert." William Gilbert, 1540-1603, private 
physician to Queen Elizabeth, was " the first real physicist and positively 
methodical experimenter known in the History of Physics before Kepler 
and Galileo." By the experiments and discoveries published in his De 
magnete magneticisque corporibus et de magno magnete tellure, Physiologia 
nova, London, 1600, later editions, Sedan, 1628, 1633, Frankfort, 1629, 
1638, he became "the founder of the doctrine of magnetism and electric- 
ity." He called the latter vis electrica. For an account of his philoso- 
phy, cf. Lasswitz, Gesch. d. Atomistik, 1, 315-321 ; for his view of vacuum, 
ibid, 319. 

Page 634, line 24, " Gassendi." For Gassendi on the vacuum, cf. Lass- 
witz, Gesch. d. Atomistik, 2, 136 sq., 168-169. 

Page 634, line 24, " Gericke." Cf. ante, p. 127, note 2. An account 
of his views is given by Lasswitz, Gesch. d. Atomistik, 2, 293-300. 

Page 634, line 25, " Digby." Cf. ante, p. 83, note 1. On Digby's phi- 
losophy, cf. Lasswitz, Gesch. d. Atomistik, 2, 188-207 ; on his view of the 
vacuum, ibid, 199. 



ADDITIONS AND CORRECTIONS 775 

Page 641, line 11, "Anglus." Of. ante, p. 634, note 1. A peculiar 
notion of White's concerning the state of the soul separated from the 
body, involved hirn in a controversy with the Bishop of Chalcedon. 
White wrote two tracts on the subject: De Medio Animarum Statu, 
Paris, 1653, 8vo, Agr. 1659, 8vo ; Besponsio ad duos Theologos Parisi- 
enses Hen. Holdenum, et alium de Medio Animarum Statu, 1662, 8vo. 
The former, together with Hobbes' Leviathan, was censured by the 
House of Commons in 1666. Archbishop Francis Blackburne, 1705-1787, 
gives an extended account of both tracts in his own Historical View of 
the Controversy concerning an Intermediate State, 1st ed., 1765, 2d, much 
enlarged, 1772 ; in Vol. 3 of his Works, Theolog. and Miscellaneous, 7 
vols., 1804. Hobbes and White frequently engaged in disputations, in 
which White commonly proved himself the abler dialectician. 

Page 657, note 1. Add : On Leibnitz's dynamical views, cf. P. Harzer, 
"Leibniz' dynamische Anschauungen, mit besonderer Riichs. auf d. 
Reform des Kriiftemaasses u. d. Entwickelung des Princ. der Erhaltung 
der Energie," in " Vierteljahrsschr. f. wissenschaftl. Philos.," 1881, Vol. 
3, pp. 265-295 ; D. Selver, Der Entwicklungsgang der Leibniz" 1 schen 
Monadenlehre bis 1695, Leipzig, 1885; M. Zwerger, Die lebendige Kraft 
und ihr Mass, Miinchen, 1885 ; M. Planck, Das Princip der Erhaltung 
der Energie, Leipzig, 1887, p. 6 sq. 

Page 679, note 1. Add : and additions thereto, infra, p. 733. 

Page 692, note 1. Add : Translated also by Duncan, Philos. Wks. of 
Leibnitz, with the title " On the Ultimate Origin of Things." 

Page 705, line 10 from bottom (of text). The Latin text reads: 
"Prteterquam finiam, adjicere placet," etc., of the first phrase of which I 
have not been able to find any better rendering than that given in the text. 

Page 712, note 1, at the end (p. 713). Add: Cf, also, Eoucher de 
Careil, Nouvelles Lettres et Opuscules inedits de Leibniz, Paris, 1857, pp. 
412-437, — ■ Note sur la loi de continuite, by the editor. The passage refer- 
ring to the letter here translated occurs p. 433. The note itself is a very 
complete and valuable account of Leibnitz's principle. Cf, also, Nour- 
risson, La Philosophic de Leibniz, Paris, 1860, pp. 221-238. 



INDEX A 

TO THE CRITIQUE OF LOCKE 



"A in theology," applied to Antoinette 
Bourignon, 603. 

"A is not B," compared with " A is 
non-B," 84. 

A posteriori and a priori, complemen- 
tary methods, 315. 

A posteriori truths, 499. 

A priori proofs, 227 ; truths, 499 ; ar- 
gument for existence of God, 503. 

" A B " who says, says " A," 471. 

Abridge, natural inclination of mind 
to, 561. 

Absolute, idea of, anterior to that of 
limits, 158; anterior to all compo- 
sition, 162; is that of the infinite, 
12, 17, 162; "in us internally," 163; 
opposed to relative, 236. 

Absolutes, the attributes of God are, 
163 ; the source of ideas, 163. 

Abstract, and concrete, how related, 
128; thoughts have need of things 
sensible, 78; entities, their reality? 
178. 

Abstracts affirmed of each other, not 
always purely verbal, 497. 

Abstraction, its process, 309 ; by it 
we arrive at essences, 497 ; gives no 
knowledge of real existence, 497. 

Abstractions, when not errors, 51 ; to 
be avoided, 225, 226. 

Academic disputes, 478, 479. 

Academicians, 421. 

Accidental and contingent, 498. 

Accidents, real beings, 154 ; when be- 
stowed miraculously, 428. 

Accidents of bodies, not arbitrarily ac- 
corded by God, 428, 431 ; are not as 
pigeons going into and out of their 
holes, 428 ; sometimes virtually 
made substances, 428 ; if not modes 
of their being or modifications of 



their substances, then miraculous, 
428; are suitable to their nature, 
431; are not removed from 'reason 
in general,' 431. 

Acervi Ruentis, problem of, 328. 

Acroamatic, 42, 272. 

Act, how forced yet voluntary, 181, 
184. 

Actes de Leipzic, 227, 319, 502; des 
Scavans, 14. 

Action, essential to substance, 11, 218 ; 
body and soul ever in, 111 ; two kinds 
of, 175, 218 ; constant because nature 
ever labors to put herself at ease, 
194; perception, a form of, 218, 219; 
motion, a form of, 218 ; that which 
takes place in substance spontane- 
ously, 218; compared with passion, 
218, 219 ; in substance when percep- 
tion is distinct, 219; a step towards 
pleasure, 219 ; a change towards per- 
fection, 219; great business of man- 
kind, 223; consists in thoughts or 
motions, 223 ; in Aristotle, 321. 

Acts 17 : 28 quoted, 153. 

Actus purus, God is, 113. 

Adamic language, the, its alleged pres- 
ervation in German, 298. 

Adequate ideas, 17. 

Adhesion of bodies, 123, 124. 

Adverb, its use, 364. 

'iEgean,' Bochart's derivation, 302. 

^Equalia sequalibus, the axiom, 540. 

Affinity, 259. 

Aggregata, 361. 

Aggregates, in what their unity con- 
sists, 235 ; artificial, 361 ; natural, 
361. 

Aggregations, beings by, 149. 

Ah ! 368. 

'Aha,' 301. 



777 



LEIBNITZ'S CRITIQUE OF LOCKE 



'Ains,' ' anzi,' 367. 

Air-gun, 466. 

Albert, the Great, 278. 

Albinus or Alcuin, 516. 

Alchemists, 601 ; called ' adepts,' 379 ; 
write only for ' sons of the art,' 379 ; 
dangerous, 601. 

Alexander the Great, 208; his dream, 
267. 

Algebra, 432, 571 ; does not require re- 
currence to ideas, 443; Vieta's use 
of letters in, 468; Leibnitz proposes 
use of figures in, 468; its use in ex- 
tracting roots, 571 ; not art of inven- 
tion, 573. 

'Allein,' its equivalents in French, 366. 

Alliance, 259. 

Alliot, Dr., his verses, 352. 

Alphabet, Chinese have no, 74; its 
connection with sounds, 78. 

Alps, derivation of word, 308. 

Amadis de Gaul, 399, 431, 546. 

Ambition, one's, should be to build 
rather than destroy, 99. 

America, lack of iron there, 525. 

American, meaning Red Indian, 90, 
359; savage regarded clocks as 
alive, 388. 

Analogy, as a rule of probability, 549 ; 
foundation of rational hypothesis, 
549; how employed by Huygens, 
550 ; to be searched after, 553 ; mira- 
cles admitted in despite of, 553. 

Analysis, 411, 412; its relation to in- 
vention, 412; infinitesimal, 440; 
Pappus on, 521, 565 ; Conriug criti- 
cises, 521 ; ultimate, difficult to ar- 
rive at, 521 ; involves a return by 
synthesis, 565. 

Anatomy, comparative, recommended, 
553. 

Ancient book, see Books. 

Andradians, 593. 

Andradius, on salvation of heathen, 
592. 

'Angebornen Ideen,' 3. 

Angel, the change in its signification, 
289. 

Angelicus Doctor, 503. 

Angels, as to their subtle bodies, 53; 
according to the Fathers, 229; ac- 
cording to Aquinas, 230. 



Anger, what, 173. 

Anglicans, 613. 

Animals, Cartesian view of, 62; con- 
servation of, in miniature, 62 ; auto- 
mata with souls, 66 ; immortal, 68 ; 
reason upon particular ideas by con- 
nection, 145; do not form abstract 
thoughts, 145 ; their love, its source, 
145; have no knowledge of num- 
bers, 145 ; have no understanding, 
178 ; rational, other than man, 244 ; 
how the idea of, is produced, 310; 
how the name is arrived at, 310; 
speech of, 352, 353; and man con- 
nected, 549, 552; and 'man,' the 
terms compared, 569. 

Animant, examples of, 125. 

Annuities, 540. 

Anselm, his argument for the exist- 
ence of God, 18, 502, 503. 

Antipathies, surprisingly common, 27, 
37; the explanation of, 27, 28; de- 
serve the attention of educators, 
29. 

Antipodes, the ground on which re- 
jected, 217, 442 ; ' pretended heresy ' 
of, 443. 

Antiquity, of value in religion, 618. 

Antisthenes on virtue, 519. 

arTiTviria, o. 

Apagogical demonstration, 491. 

Ape, a human ancestor, 353. 

Aphorism, 476, 486. 

Apium, 394. 

Apollonius, 14, 108, 402, 416, 463, 573. 

"Apologie du genre humain" of M. 

Fabritius, 21. 
Appellative names, 309, 
Apperceptions, past, 46 ; depend on 

attention and order, 76 ; we are often 

without, 166. 
Appetite, and hunger, distinguished, 

170; tends to pleasure rather than 

happiness, 207. 
Appetitions, what? 177; apperceptible, 

177 ; tend to go to their end directly, 

not wisely, 195; can be directed by 

reason, 196; motus primo primi are 

towards joy, 195. 
Apuleius, ass of, 243. 
Aquaviva, Claudio, 619. 
Arabia Deserta, 259. 



779 



Arabs, influence on medicine, 371. 

Arbitrariness, not in ideas but in 
words, 325. 

Archsei, 67. 

Arcbelaus, bis "law makes virtue," 
519. 

Archimedes, 93; demonstrations in 
physics, 414, 415 ; on equilibrium, 
415, 41(5 ; has shown a square equal 
to a circle, 424; further investiga- 
tions by him regarding circle, 424; 
on curvilinear s, 473 ; how he arrived 
at quadrature of parabola, 475 ; his 
definition of straight line, 522; on 
the spiral, 573. 

Areopagites, their practice of releasing 
one whose case was too hard to de- 
cide, 186. 

Argumenta, 398. 

Arguments, the two, of the rhetori- 
cians, 529; mixed, 530; from greater 
number, 530; Nicole on, 530. 

Arguments in form, what? 559; a 
recto ad obliquum, 560, 564; four 
sorts, ad verecundiam, 576 ; ad ig- 
norantiam, 576; ad hominem, 576; 
ad judicium, 576; ad vertiginem, 
577. 

Aristides, 392. 

Aristippus, on happiness, 518. 

Ariosto, 398. 

Aristotle, 392, 418, 466, 495, 521 ; his 
entelechy, 66, 174 ; on time, 156 ; on 
free acts, 180; on future life, 208; 
on probability, 214 ; his definition of 
motion, 320; his definition of light, 
321 ; on materia prima, 383 ; defects 
arising from the fact that some of his 
writings were posthumous, 384; defi- 
nition of man, 384; defended, 385; his 
"Prior Analytics," 414, 416; as a 
philosophic writer, 416; assump- 
tions, 479; his nadoXov wpQrov, 488; 
additions to what he left concern- 
ing body, 495 ; his frrovfjievri, 495; bis 
estimate of metaphysics, 495 ; how 
he referred accident to matter, 498; 
his " Posterior Analytics," 521; his 
"Topics," 541; Locke's estimate of, 
557; his disposition of the prem- 
ises in the syllogism, discussed, 568 ; 
his expression " B is in A " justified 



by reference to ideas, 569; is he 
" saved"? 593. 

Arithmetic, its propositions innate, 76, 
78; can be presented apart from 
sight or touch, 78 ; awakened in ns 
by touch, 78. 

Armenian books, 372. 

Arminius, 72. 

Arnauld, his " New Elements," 463, 
464; argues against insensible 
changes, 618. 

Arrangement, its importance, 475. 

Ars Combinatoria, pirated, 434. 

Art of Signs, needed, 573. 

Arts, advantage of cultivating, 525, 
526. 

Ass, golden, of Apuleius, 243. 

Assassins, 196, 197. 

Assent, degrees of, 529; often based 
on memory of previous reasonings, 
532, 533 ; such use of memory in, its 
advantages and disadvantages, 533 ; 
as a guide of action, 534, 535; its 
varieties, 537, 538 ; as assurance, 538; 
as confidence, 538; as firm belief, 
538; has varying degrees of proba- 
bility, 538 ; granted to Miracles and 
Revelation, 553 ; founded on motives 
of credibility, 554; supernatural, 
founded on Divine Grace, 554. 

Association of ideas, a non-natural 
often observable, 281, 282; ground 
of acquired sympathies and antip- 
athies, 282; affects intellectual 
habits, 282; source of the non- 
natural, 283; depends on associ- 
ation of perceptions, 283 ; strength- 
ened by repetitions, 283, 284; 
strengthened by " vehemence of im- 
pression," 284; influenced by "au- 
thority, party, custom," 284. 

Assumptions, Aristotle's, 479. 

Assurance, how belief becomes, 538. 

Assyrians, doubts about history of, 545. 

Asyllogistic, conclusions, 560, 561. 

Asymptote, 209, 523. 

Atom, defined, 53, 54. 

Atoms, 65, 68, 239; of Epicurus, 126, 
132; of Democritus, 309; fortuitous 
concourse of, folly, 615. 

Attention, 115, 165, 166; division of, a 
means of securing sleep, 115. 



780 



LEIBNITZ'S CRITIQUE OF LOCKE 



Attraction over distance, 56. 

Attributes and modifications, distin- 
guished, 58. 

Augustan Confession, 612. 

Augustine, 410; on eternal truths in 
Divine intelligence, 516; damning 
infants unbaptized, 594; his "De 
Utilitate Credendi," 616. 

Augustus, 308 ; his " Brevarium Im- 
perii," 610. 

Augustus, Elector of Saxony, an 
alchemist, 339. 

Aumont, Due d', an antiquarian, 547. 

Australians, supposed invasion of, 456. 

Authority, how far to be yielded to, 
616. 

Avarice and ambition, the principle at 
bottom of both wholesome, 212. 

Avarice, its application to different 
complex ideas, 313, 314. 

Aventin, 546.- 

Averroists, 53. 

Axioms, are they indispensable? 12; 
should be demonstrated, 18, 72, 99, 
107, 175, 473, 518 ; truths other than 
self-evident, 464 ; secondary, should 
be reduced to primitive, 464 ; primi- 
tive, 464; primitive, are identicals 
and undemonstrable, 464; its par- 
ticular and more general meaning, 
469; in what sense prior to other 
parts of knowledge, 470; other 
truths alleged to be as evident as, 
471 ; the result of discarding, 472 ; 
their use in geometry, 473; should 
be assumed with caution, 518; when 
the secondary may be emjiloyed, 524 ; 
their principal use to connect ideas, 
527. 

" B in mathematics," used by Bertrand 
la Coste, 603. 

Babylonians, doubts about mathe- 
matics of, 416 ; doubts about history 
of, 545. 

Baldness, the problem concerning, 328, 
353. 

Baptism, conditional, 244, 343, 344. 

Barantoli, could not understand ' hal- 
lowed,' 103. 

Barbarism and cultivation contrasted, 
96, 97. 



Barclay. Quaker theologian, 599. 

Barner, his Prodromus, 487 ; suggests 
abridgment in medical works, 488. 

Battles, almost no good account of, 
543 ; those of Livy imaginary, 543 ; 
Dahlberg's plans of, 543. 

Bauhin, 308. 

Baumgarten, his story of the Santon, 
89. 

Bayle, 66, 507. 

Beasts, men distinguished from, by 
innate knowledge, 76. 

Beatific vision, 575. 

Becan, 303. 

Beda, 295. 

Being, have idea of, because we are 
beings, 76; knowledge of , how de- 
rived? 100; some have no word 
for, 103; God, finite spirits, and 
matter may be modifications of a 
common, 154; corporeal, knowledge 
of, given in sensation, 229 ; spiritual, 
knowledge of, given in sensations, 
229; thinking, if thought comes 
from, such Being is God, 501 •, one 
original, reasonable to believe that 
there is, 501 ; thinking, can it come 
from a non-thinking source ? 505; 
eternal first, cannot be matter, 506. 

Beings, outside of us, are they demon- 
strable ? 469 ; eternal, may there be ? 
501 ; may this state of things origi- 
nate in a concurrence of ? 501. 

Belgian Confession, 612. 

Belief, how it becomes assurance, 538 ; 
not according to wish, but sight of 
most apparent, 615; can be indirectly 
influenced, 615; founded on slight 
reasons, explained, 616. 

Bellarmine, 621. 

Bernier, 64. 

Beverovicius, his book on medicine, 
624. 

Beyerling, 622. 

Beza, his views of Eucharist, 612. 

Blind, their opinion of scarlet, 128, 
321; have learned geometry, 139; 
may learn optics, 139; can speak 
pertinently of light and color, 305. 

Bochart, 302. 

Bodies, "two cannot be in same place 
at same time," the statement con- 



781 



sidered, 83; impenetrability of, 83; 
extension of, and equality of space, 
not inseparable, 127; act only by 
impulse, 132 ; do not act where they 
are not, 132; in what sense neces- 
sary agents, 183; do not remain 
same in appearance, 240; of entel- 
echies are machines, 362 ; of entel- 
echies, imperishable, 362; of en- 
teleehies, an infinite replication of 
inanimates, 362. 

Body, never without motion, 11, 24, 
47, 110; least impression upon, 
reaches its entirety, and therefore 
to part whose motions correspond 
to actions of soul, 25 ; Leibnitz al- 
leges a change in Locke's views as 
to, 38; and mind, their differences 
not modifications, 58; and mind, 
exact correspondence between, 117, 
182; to say it is extended without 
parts unintelligible ? 118 ; acts (agit) 
when spontaneity in its motion, 219 ; 
is passive (patit) when urged or hin- 
dered by another, 219; possesses 
an image of substance and action, 
219 ; as composed of parts, not one 
substance, 219 ; its unity comes from 
the thought, 219; like a flock, 219; 
organized not the same but equiva- 
lent, 241 ; Descartes' Adew of, 483 ; 
can it be only in one place at same 
time, 466, 589; substance of, does 
not consist in extension or dimen- 
sion, 612; glorious of Jesus Christ, 
612 ; glorious, its local presence, 612 ; 
glorious, its sacramental presence, 
612; glorious, its miraculous pres- 
ence, 612. 

Bodies, mechanical affections of, colors, 
sounds, etc. how explained, 441; 
movements of, correspond to, but 
do not resemble, affections of soul, 
441 ; their connection with soul ex- 
plained by Pre-established Har- 
mony, 441; the statement that two, 
cannot be in the same place at the 
same time, discussed, 466 ; the state- 
ment true if body be an impenetra- 
ble mass, 466 ; the statement not true 
of real body, 466 ; the statement 
only true in natural order of things, 



467 ; knowledge of, being increased, 
495 ; knowledge of, acquired by ex- 
perience, 524; knowledge of, ac- 
quired by rational and regular 
experiment, 524; investigation of 
internal parts of, most useful of our 
present efforts, 552. 

Boehme, Jacob, 298 ; Teutonic Philoso- 
pher, 603; believed to make gold, 
603. 

Bohlius, 366. 

Boldness, 223. 

Bolsec, his slanders on Calvin, 545. 

Boniface, 443. 

Bonosus, wherein his drinking might 
be praised, 263. 

Book, never formed by throwing type 
together pell-mell, 422. 

Books, ancient, to be investigated, es- 
pecially on medicine, 372 ; Chinese, 
3f2. 

Boreas and the traveller's cloak, 
613. 

Borgia, Francis de, how he reduced 
his wine, 193. 

Bouhours, his Art de Penser, 144. 

Bouillaud upon the spiral, 573. 

Bouquetm, ibex, 394. 

Bourignon, Antoinette do, an enthusi- 
ast, 599, 602, 603. 

Boutan, 91. 

Boyle, Chevalier, 324; denies absolute 
rest, 47 ; concludes that everything 
in nature takes place mechanically, 
527. 

Brahmins, 372. 

Brenner or Pyrenees, 308. 

Brocards, require reform, 486. 

Brugnolus, 106 ; Bruguol, 107. 

Brusquer, 370. 

Brutes, their knowledge, 44; their 
"consecutions," 44; have imperish- 
able souls, 62, 113. 

Brutus, origin of name, 308; and the 
Britons, 546. 

Bubbles, as memories, 513. 

Bucephalus, 308. 

Buratini, 150. 

Buriclan's ass, 116. 

Burnett, Thomas, a correspondent of 
Leibnitz, 6. 

' But,' its different significations, 366; 



782 



LEIBNITZ'S CRITIQUE OF LOCKE 



its equivalents in French and Ger- 
man, 36(J; its derivation, 3G7. 

Caedmon, 295. 

Cassar, 308, 575. 

Calvin, his strong views of Eucharist,, 
612. 

Caraillus and the Gauls, story con- 
tradicted, 545. 

Campanella, 67. 

' Candle of the Lord,' 437. 

Cannon-halls, why piled ? 570. 

Canon, general, 468. 

Capacity, 149, 174. 

Capito, SOS. 

Cardan, 67 ; on the logic of the proba- 
ble, 566. 

Caribbees, their cruelty, 89. 

Carlowitz, peace of, 259. 

Carrington, his life of Cromwell, 543. 

Cartesians, 62, 66, 67, 68, 113, 126, 133. 

Cartesians, their appeal to ideas, 13; 
perplexed by souls of brutes, 62; 
on space and matter, 128; on space 
and extension, 129; on transfer of 
motion, 176; on souls giving new 
direction to force, 233; cannot 
demonstrate real external existence, 
319; their first truth, 410, 460 ; their 
argument (the Anselmic) for exist- 
ence of God, 502; their grooved 
particles, 613. 

Casati, 176. 

Casaubon on the Sorbonne, 478. 

Casimir, King of Poland, and his forest 
child, 344. 

Cassowary, sign of a complex idea, 357 ; 
exact idea of its skin might distin- 
guish it, 357 ; " wide nails " wanting 
to make it a man, 3S4, 385. 

Castor and Pollux, with one soul, 
114. 

Cause, final, 224, 556 ; proximate for- 
mal, 337. 

Cause and effect, 237 ; can they be ex- 
pressed apart from action ? 224. 

Causes, efficient, parallel in all worlds, 
440 ; final, various, 224, 440. 

' Cavalcar,' 222. 

Cebes, Table of, 436. 

Celery-plant, 394. 

Censors, 593. 



Censures, Theologic, 537. 

Cependant, its use, 367. 

Certainty, in human knowledge, 15 ; 
of truth and of knowledge, 453 ; ex- 
perimental, 460 ; moral or physical, 
distinguished from metaphysical or 
necessity, 462 ; what ? 513. 

Certitude, mathematical, 13 ; the place 
of particular demonstration in, 318, 
403; depends on certain universal 
propositions, 403. 

' Chain of reasoning,' 561. 

Chance, what? 203; a mathematical 
treatment of games of, 541. 

' Chancellor of England, the,' 526. 

Change, what ? 174. 

Characteristic, a universal, 453, 469. 

Chemistry, its wfido successu, 331. 

Chemnitius, 592. 

Chess, Arabs play, by memory, 152. 

Chiliagou (figure of a thousand sides) , 
269, 272, 27.3. 

Children, why they have no knowl- 
edge of innate principles, 76; their 
exposure, 89. 

Chimerical, difficulty of affixing epi- 
thet, 277. 

China, race-mules in, 345 ; Jesuits in, 
594. 

Chinese, geometers, 22 ; alphabet, no, 
74; drawings, 136; writing, 140; 
language, 287, 452,453 ; Golius's opin- 
ion about language, 287, 292 ; salva- 
bility of, according to Jesuits, 594. 

Choices, suspensory power exists over, 
186; different, prove varying opin- 
ions of good, 207; future life should 
influence our, 208; man's, never 
wrong if present alone regarded, 
208. 

Christmas eve, superstition concern- 
ing, 470. 

Chronicles, II., 6:18, 158. 

Chrysostom, on natural piety, 591. 

Church, ambiguity of term, 271 ; its 
relation to controversies, 617, 618. 

Cicero, 308; on the sight of the beauty 
of virtue awaking love to it, 192; 
on the praise of virtue, 264; on the 
existence of God, 500. 

Circle, quadrature of, 603. 

City of God, 53. 



INDEX A 



783 



Clair-confus conceptions, are they pos- 
sible to the blind ? 140. 

Clauberg on sources of German, 303, 
304. 

Clavius, 424. 

Clearness, a species of certainty, 513. 

Clelie, 223. 

Clement, Second, his family, 544; of 
Alexandria, 591. 

' Coaxare,' as a stem, 298. 

Codex Argenteus of the Euxine Goths, 
295. 

Codex juris gentium diplomaticus, 
167. 

Cogitationes csecse, 191. 

Cohesion, causes traction, 54; in all 
bodies, 125 ; its explanation as diffi- 
cult as that of thought, 231 ; not es- 
sential to extension, 231; does it 
arise from pressure of ambient 
fluid ? 231, 232. 

Collective unity, what ? 149. 

Collius, 593. 

Color of gold would disappear if senses 
more penetrating, 227. 

Colors, their common properties, 323 ; 
their divisions, 323; intimate nat- 
ure of, determined by analogy, 549. 

Comenius, his air-gun argument, 466 ; 
his "LuxinTenebris," 604; pro}3he- 
cies popular, 604. 

Compactness, 123, 126. 

Comparison, 144. 

Compass, 525. 

Complex ideas, 5, 147-149. 

Composition of ideas, 144. 

Compossible, capable of existing to- 
gether, 277, 334. 

Compound direction of volition, 200. 

Compulsion, physical, what? 182, 183; 
moral, what? 184. 

Conatus, 177, 224, 

Conceptivity, creature's measure of 
nature's power, 60. 

'Concreate,' 80. 

Concrete terms, best to be employed, 
226. 

Concrete and abstract, how related, 
128. 

Concurrence, 144. 

Condensation, 124; there is none, 127. 

Condensations, real, 466. 



Conditions, an early thesis upon, re- 
ferred to, 434. 

Cone, an illustration of the gliding 
of the sensible and rational into 
each other, 549. 

Confidence, 538. 

Configuration can abide specifically 
without abiding individually, 240. 

Confucius, Jesuits' opinion regarding, 
594. 

Conjectures, 529, 538. 

Conjunctions, 364. 

Connaway, Countess of, 67. 

Conring, 520 ; his criticism on Pappus, 
521. 

Consanguinity, 259. 

Conscience, borne witness to by best 
part of race, 90 ; remorse of, 91 ; 
" laniatus et ictus " of, 91. 

Conscious, we are not always, of hab- 
its and stores of memory, 46. 

Consciousness of objects dependent on 
attention, 115; what? 245; "silent 
in forgetfulness," 247 ; cannot be 
transferred, 247, 248; as a represen- 
tation, 248. 

Consecutions of animals, 69. 145. 

Consent, general, may come from tra- 
dition, 72. 

Consequence discussed, 213. 

Conservation of souls, 52 ; of animals 
in miniature, 62. 

Consideration, 166. 

Consistence, 126. 

Consubstantiation, 611, 612. 

"Containing" and "contained" not 
same as "whole " and " part," 569. 

Contemplation, 165, 166 ; of acquired 
knowledge, 142; of innate knowl- 
edge, 142. 

Contingence, angle of, 258. 

Contingent truths, 183. 

Continuity, law of, 50, 334, 552; ap- 
parently violated for reasons of 
beauty, 552; why not evident be- 
tween man and beast, 552. 

Continuum, 152, 160. 

Contradiction, axiom of, a first princi- 
ple, 14; made use of always, 77; 
how it may be employed in logic, 
406, 407; how it may be employed 
in mathematics, 406, 



784 



LEIBNITZ'S CRITIQUE OF LOCKE 



Contradictories, 23. 

Contrition, the act of, what ? 591 ; how 
it saves, 591. 

Controversy, often due to the disput- 
ers "speaking a different language 
while meaning the same thing," 388. 

Conversation, its nature, 341 ; angelic, 
341. 

Conversion, principle of, how used in 
logic, 407. 

Copernican hypothesis, one opposed 
to it maintained with zeal, 613. 

Copernicans, 70. 

Copernicus, 419 ; the detriment of sup- 
pressing his views, 614. 

Coptic books, 372. 

Copy, force of a, as evidence, 541 ; 
copy of a, its value in evidence, 541 ; 
adds no weight to the original, 545. 

Corban, 327. 

Corinthians, II., 5: 10, 447. 

Corollaries, 434. 

Corpus delicti, 538. 

Corruptio optimi pessimal, 482. 

Coste, Pierre, his translation of Locke's 
Essay, 7, 27. 

Coste, La, Bertrand, 603. 

'Couaquen,' see 'Quaken,' 298. 

Councils, advantage and disadvantage 
of, 617; their sphere according to 
Henry Holden, 617, 618. 

Count, to, what? 160. 

Creation, continuous, 16, 511 ; Locke's 
statement concerning, that "its mys- 
tery is open to some extent to pro- 
found meditation," 509; probable 
that Locke's hinted explication is 
Platonic, 510; not more inconceiv- 
able than movements produced in 
bodies by volition, 510; a gradual 
connection in all its parts, 549; the 
boundaries of its sensible and ra- 
tional regions difficult to define, 549. 

Creator, ruled by nature of things, 431 ; 
produces and conserves only what 
suits the nature of things, 431 ; pro- 
duces only what can be explained 
by their natures, 431 ; gives no acci- 
dental powers detached from inward 
constitution, 431 ; acts according to 
general reason, 431; knowledge of 
his acts, because of their reasonable- 



ness, not beyond us, 431 ; difficulty of 
comprehending his work not in their 
reasons but their multitude, 431. 

Credibility, motives of, 554, 579, 585. 

Credulitate, de, oath, 530. 

Crime, what ? 262. 

Criterion of objects of sense: the con- 
nection of the phenomena, 422 ; veri- 
fication by truths of reason, 422 ; yet 
does not afford highest certitude, 422. 

Criticism, 372. 

Cromwell, Oliver, did he ever leave 
the British Isles ? 543. 

Crusca, La, function of, 18. 

Ctesias, disagrees with Herodotus, 545. 

Cudworth, 65. 

Cuivis potest accidere, quod cuiquam 
potest, 492. 

Cyrano, de Bergerac, his "Voyages," 
399 ; fancies of, concerning beings in 
the sun, 228, 229; in the moon, 551. 

Cyrus, doubts about, 545. 

Dahlberg, Count of, his plans of the 
battles of Charles Gustavus of 
Sweden, 543; his defence of Riga, 
543. 

Dalgarno, George, his artificial lan- 
guage, 292. 

Darapti, 568. 

Day and night, their succession in 
twenty-four hours uot necessary, 43. 

De Dominis, 442. 

De officio viri boni circa futura con- 
tingentia, 605. 

Deaf and dumb, those born, enquiries 
concerning, 140. 

Death, a sleep, 49, 52; cannot last 
always, 53; separation in, proves 
movement of soul, 229. 

Decahedron, a regular, an impossible 
combination, 315, 354. 

Deduction, as an instinct and as a log- 
ical power, 88 ; employed by all, 88. 

Definition, nominal, 17, 316, 339; real, 
17, 316 ; as applied to substances and 
predicates, 317; empiric, only pro- 
visional, 324; external marks in, 
sufficient for exact, 339; should be 
capable of being substituted for 
name, 340; dependent on exterior 
of bodies imperfect and provisional. 



INDEX A 



785 



342; often several, for an object, 
392; whose possibility appears at 
once to involve intuitive knowledge, 
410; adequate, contains intuitive 
knowledge, 410. 

Degrees of assent, 532. 

Deity, knowledge of, given by nature, 
72 ; confirmed and rectified by knowl- 
edge, 72; readiness with which men 
have received notion of, if tradi- 
tion or not, proves that it comes 
from depth of soul, 72. 

Ae? Triffreveiv tov fiavddvoura, 519. 

Democritus, G5 ; his promise of another 
life, 66 ; his correct surmise regard- 
ing Milky Way, 277 ; atoms of, 309 ; 
the principle of individuation in con- 
nection with his atomic theory, 309. 

Demonstration, defined, 22, 556 ; phil- 
osophic, why inferior to mathemat- 
ical, 416, 417 ; not to be always ex- 
pected, 512 ; mathematical, its stages, 
556. 

Demonstrative knowledge, not so clear 
as intuitive, 411 ; illustrated by a 
series of mirrors, 411. 

Demonstrative science founded on in- 
nate knowledge, 77. 

Denial is positive, 131, 289. 

Denominatio pure extrinseca, cannot 
exist metaphysically, 236. 

Denomination, intrinsic, 456; extrin- 
sic, 456. 

Deo, omnia in, videre, 3. 

Desargues, on tints and shades, 137. 

Descartes, 62, 64, 67, 123, 466; advo- 
cated innate idea of God, 70 ; on fal- 
laciousness of senses, 134 ; on limit- 
less matter, 154; makes infinite 
equal to indefinite, 154 ; his idea 
about pineal gland insufficient, 230 ; 
his affection for squint-eyed persons, 
283 ; his idea of body, 483 ; denies a 
vacuum, 483; at La Fleche, 504; on 
Bacon's method, 526; his expected 
telescope, 551 ; his hypothesis uncon- 
firmed, 552 ; employed the knowledge 
of his time, 552 ; on solution of equa- 
tion of fourth degree, 572; applies 
calculus to geometry, 573. 

Description may fall upon the i 
ble, 398, 399. 
3e 



Desire, founded on uneasiness, 49; 
what? 168-170, 189; its relation to 
pain, 170 ; accompanies the passions, 
198; in midst of joy leads to new 
actions and neglect of present pleas- 
ures, 198; produces voluntary ac- 
tion, 199 ; aroused by happiness, 200 ; 
its suspension is man's freedom, 
202 ; its advantage, 202, 203 ; occurs 
through insensible lassitude, 202 ; oc- 
curs through contrary inclinations, 
202; may be brought about by 
methodical mental processes, 203; 
brought about by direct power of 
mind, 204. 

Despair, what ? 172, 173 ; reasons 
against, 437. 

Despreaux, 97. 

Determination, of will, what? 183; 
useful and necessary, 205; needful 
to effective choice, 205; does not 
necessitate, but incline, 206 ; an in- 
clination rather than a necessity, 
206; when founded on reason gives 
largest freedom, 206 ; resting on 
final result necessary to freedom, 
205 ; its strength in superior beings 
does not limit their freedom, 205; 
"confirmation" of unfallen angels 
rests on, 205 ; is in God, and is not 
inconsistent with perfect divine free- 
dom, 206. 

Determined, all things in soul are, 
15. 

Diagram, 435. 

Dialogue, advantages of that form of 
writing, 42. 

" Diaphanous " in Aristotle, 321. 

Die cur hie, 166, 203. 

Dichotomies, 200 ; their use, 312. 

Dictionaries of simple ideas observed 
in individuals of each species desid- 
erated, 394 ; with small illustrations, 
recommended, 394 ; Chinese have il- 
lustrated, 395; "the most excellent 
of," 49. 

Difficulties often created and then 
lamented, 460. 

Digby, Chevalier, 83. 

Digests, 272, 486. 

Diogenes wishes to make a Platonic 
man, 385. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Diophant, 573; on reduction of equa- 
tions, 571. 

Dioscorides, 371. 

Discernment, 143-147. 

Discovery, finds general truths, 474; 
a chance example often assists in, 
475 ; ways of, might be systematized, 
476; sometimes arrived at by ra- 
tional but extended circuits, 476. 

Discussion, art of, its importance, 477 ; 
frequent in beginning of Reforma- 
tion, 477 ; art of, needs remodelling, 
478; "last word" in, 478; assump- 
tions in, 479; confusion in, from 
want of axioms, 479 ; rules and ex- 
ceptions in, 480; replications and 
duplications in, 480 ; cavilling in, 
reprehended, 481 ; its academic for- 
mulae not to be paraded in conver- 
sation, 482; of matters of faith, 
regarded by some as of the devil, 
610. 

Disease, like a plant or animal, 488. 

Disparates, what ? 405, 406. 

Disposition, what ? 223. 

Dispositions, remains of past impres- 
sions in the soul, 143 ; conscious of, 
on occasions, 143. 

Distance, what? 149; of places and 
times, congruity between, 209. 

Distinct, 267. 

Distinctions, virtual, of the Scotists, 
587. 

Diversity, involves an internal princi- 
ple of distinction, 238; time and 
space are helps to recognize, 238 ; not 
destroyed by interpenetration, 238. 

Divine grace, a pleasure, 192. 

Divini, Eustachio, 613. 

Dogmatists, 420. 

Drabitius, 605. 

Draudius, 626; his method criticised, 
627. 

Dreaming, 165, 166. 

Dreams, absence of, no disproof of 
soul's activity, 115 ; leave marks on 
brain, 117 ; shall we infer from inco- 
herency of, that rational thought de- 
pends on body ? 117 ; of persons and 
places before they have been ceen 
by dreamer, 514. 

Drinking, a virtue, 263. 



Drunkard, under the illusion of time, 
209. 

Duration, 155-158, 220; idea of, how 
awakened? 156; could perceptions 
give idea of? 156; how measured? 
156 ; not comprehensible in all its 
extension, 158 ; indicates possibilities 
beyond supposition of existences, 
158 ; infinite, an easier conception 
than an infinite expansion of space, 
158. 

Duties and sins, how they differ from 
virtues and vices, 261, 262. 

Dynamics, 440. 

Eau, its derivation, 302. 

Ebenbitar, 371. 

"Ecclesiastical Polity" of Hooker, 
quoted, 566. 

Echant'dlon cle Reflexions sur V Essay 
par Locke, 6. 

Economic faculty as an indicial term, 
627. 

Ecstasy, 165, 166. 

Ecthesis (mathematical) , 464, 556. 

Effect, often confounded with cause, 
137. 

Effort, 174. 

Ego, spiritual, preserved, 241 ; has no 
parts, 247 ; same physical preserved, 
247. 

Egyptian, geometers, 22, 416; vases 
religiously decorated, 390. 

Elbe, 308 ; applied to all rivers in Scan- 
dinavia, 308. 

Embryology, question in, 347. 

Empiricism, liable to mistake, 44 ; un- 
reasoning, 556. 

Enchiridion sapientise, proposed, 610. 

Encyclopedia, 623-625. 

Endoxon, 418. 

Enigma, its use, by Pythagoras, 379 
by Orientals, 379. 

Entelechy, 66 ; Aristotle's view of, 174 
Leibnitz's view of, 174. 

Entelechies, when they are souls, 175 
perception belongs to all, 218; sub- 
stantial unities, 234 ; primitive, their 
bodies machines, 362. 

Enthusiasm, Locke's thoughts on, 31- 
37 ; defined, 32, 33, 596, 597 ; difficult 
to rescue its victim, 33, 600, 601 ; its 



INDEX A 



787 



ground examined, 33, 34, 596; how 
to guard against, 35 ; rests on a feel- 
ing of revelation, 597 ; at first had a 
good signification, 598. 

Enthusiast, a young lady, 600. 

Enthusiasts, may hecome a dangerous 
sect, 600. 

Enthymeme, 73, 481, 559, 563, 564. 

Envy, what ? 173. 

Epictetus, 495. 

Epicurean atom, 54 ; tendency to mo- 
tion when at rest, 380 ; tendency to 
motion is gravity, 382. 

Epicureans, 501. 

Epicurus, 126 ; his life exemplary, 535. 

Epiphany, 361. 

Episcopius, 179. 

Equation, method of solution often 
depends on good luck, 572. 

Erasmus, 591. 

Errors, arise from false principles as- 
sumed as once proved, 37; arise from 
carelessness in deduction, 37 ; arise 
from the Mas given hy emotion, 37, 
38; arise from little time left for 
study hy necessary occupation, 607 ; 
of people of leisure, 608; of people 
of narrow logical power, 608; are 
they dependent on nature of soul or 
lack of exercise ? 608, 609 ; often due 
to power of example, 609; enter- 
tained hy those who lack will to 
study, 609; from false measures of 
probahility, 610 ; arise from earliest 
education, 611; arise from believing 
teachings of an accepted communion, 
611; from accepted hypothesis, 613 ; 
from improperly understood author- 
ity, 616; the sin of, 607, 616; not so 
common as apparent ? 620. 

Essay, concerning Human Understand- 
ing, by Locke, its translation into 
French, 4, 27, 65 ; its successive edi- 
tions and abstracts, 4, 26, 27 ; its con- 
tents, 4, 6, 70; its translation into 
Latin, 37, 65 ; errors corrected in, 
and additions made to, 26, 27 ; com- 
mended, 567. 

Essence, its import, 315; 'nominal' 
and 'real,' is the terminology cor- 
rect? 315, 316, 385; and definition 
distinguished, 316 ; and property dis- 



tinguished, 317 ; how perpetual, 318 ; 
into which opinion enters, 328; half 
nominal, 328 ; is it confined to sorts 
or does it enter into individuals ? 331 ; 
real, when chimerical, 356; more 
than signs, 356 ; words may be used 
regarding, 387; if unknown in some 
respects, may be known in others, 
387 ; our ignorance of, does not pre- 
vent their existence, 387 ; a real, may 
be assumed by means of a reciprocal 
proposition as to genus and species, 
457; of substance, makes its quali- 
ties emanate from its depths, and 
makes itself known by them, 460; 
knowledge of, arrived at by abstrac- 
tion, 497 ; aud existence, 498 ; natu- 
ral as applied to accidents, 498. 

Eternal truths, their reality in connec- 
tion with ideas, 516 ; require either 
created or Divine mind for existence, 
516 ; the Divine mind their constant 
region, 516. 

Eternity, how notion originates, 158; 
in what sense a positive idea of, pos- 
sible, 164; we have a just idea of, 
but no image, 274. 

Ethics, a true philosophy strengthens, 
66; though demonstrative has its 
innate principles, 85, 86 ; its maxims 
often only convenient rules, 86 ; its 
truths not independent, 86 ; has prin- 
ciples which are not demonstrable, 
86; has principles not known purely 
by reason, 86 ; its maxims sometimes 
known by instinct, 86, 89; deriva- 
tive truths of, 87 ; depends on dem- 
onstrations furnished by natural 
light, 89 ; are not perceived at once, 
89; obedience usually unreasoning, 
90; its impulses not invincible, 90; 
natural impressions serve in, only as 
aids to reason, and indices to the 
plan of nature, 91 ; natural instincts 
not beyond, but in spite of exceptions 
tend to what is right and decent, 91 ; 
if geometry were as much opposed 
to men's inclinations as, it would be 
equally contested, 93; best treated 
by definition, 392; and metaphysics, 
495 ; geometry might be applied in, 
524; what it comprises, 621. 



788 



LEIBNITZ'S CRITIQUE OF LOCKE 



Eucharist, opinions concerning, 611 ; 
participation in, of thought, 612. 

Euclid, 14, 22, 44, 93, 108, 403, 404, 416, 
463, 465, 467, 471, 473, 491, 522, 523, 
613; does not expressly use "the 
whole is equal to the sum of its 
parts," 471; does use " the whole is 
greater than its parts," 471 ; axioms 
of, diminished hy Roberval, 473; bis 
definition of a straight line obscure 
and gives rise to difficulties, 522 ; his 
demonstrations, arguments in form, 
559, 560. 

Euphorbus, 21, 100. 

Evangelicals, their opinions on the 
Eucharist, 611. 

Evidence, luminous certainty, 513. 

Evil, what? 167, 200, 202, 260; its ad- 
vantages, 170. [198. 

Evils, present, possible remedies for, 

Example, its force, 609. 

Exclusion, method of, 413. 

Excommunication, 264. 

Existence, our own, known by intui- 
tion, 18, 439, 498, 499; of God, by 
demonstration, 18, 439, 499, 500; idea 
of, whence ? 130, 220 ; real , one of the 
"four sorts of agreement or disa- 
greement," 400 ; beyond the mind, 
how determined, 419 ; of things 
besides God and ourselves, how 
known, 499; earliest apperceptions 
of, furnish earliest experiences, 499 ; 
of God, the Lockian, Anselmic, and 
Cartesian arguments for, 499-505 

Exoteric, 272. 

Experience, twofold, 4 ; not sole source 
of truth, 11 ; not everything in 
physics, 18; never assures of per- 
fect universality, 22 ; never assures 
of necessity, 22 ; determines to 
thoughts but does not furnish ideas, 
110 ; its first truth, 501 ; not a good 
thing to judge by, 582. 

Experimenting, Bacon put art of, into 
maxims, 526. 

Extended, the, what? 152. 

Extending ideas, 144. 

Extension, what ? 152, 160, 163, 220 ; 
different from matter, 155 ; not nec- 
essary to existence, 430. [129. 

Extensions, are there two? 127, 128, 



External causes of sensation, reality 
of, 511, 512; if a dream, yet suitable 
to circumstances and hence satis- 
factory, 512 ; have an assurance of, 
as certain as pleasure or pain, 512. 

Fabri, his " Summa Theologiae," 586; 
his view of movement of sun, 613. 

Fabritius, or Fabricius, M., 21, 102. 

Factum, in, the action, 486. 

Faculty, more than the possession of 
ability without using it, 80 ; requires 
not merely object but disposition 
towards object before it will act, 80 ; 
not full explanation of, mind's easy 
consent to certain truths, 81 ; naked, 
does not exist, 110, 143, 174, 204, 428. 

Faculties, have disposition and ten- 
dency to action, 110 ; how they act, 
179 ; secondary, more than relations, 
185 ; naked, little goblins as it were, 
431 ; their limits and sphere, 525 ; 
lessons to be drawn thence, 525. 

Fairies, how their transformations 
would be regarded, 244, 245. 

Faith, the analysis of, 555; what? 580, 
583; grounded on reason, 580, 582; 
and reason, their distinctive limits, 
583 ; proper matters of, 584 ; requires 
internal grace of Holy Spirit, 585 ; 
does not refuse a knowledge of 
reasons, 585; cannot receive what 
subverts all belief, 587; implicit, 
Bellarmine on, 621; involves a rea- 
sonable docility, 621. 

False judgment, in allowing the " dis- 
tance " of a pleasure or pain to 
determine its value, 209; depends 
on limited capacity of mind, 210; 
by which the absent is annihilated, 
210; distinguished from bad taste, 
210 ; as to the greatness or certainty 
of consequences, 212; in hazarding 
a greater good for a less, 213 ; causes 
of, 214; the reckoning required to 
escape, 214, 215 ; in accepting first 
pleasure which comes to hand, 216 ; 
to expose oneself to a possible dan- 
ger in next life, 217. 

Falsehood, its nature, 452. 

Family names, 258. 

Fanatic, 33, 596. 



789 



Fear, what? 172. 
Feel, without knowing it, 191. 
Felicity, what? 87; reason prompts 
to, 87. 

Ferrari, Lewis, his equations, 572. 

Feuille morte, an idea of the color, 
how conveyed to peasant, 391. 

Figural arrangements, 145. 

Figure, what? 151, 160; scarcely a 
simple mode, 152 ; does not pass cle 
subjecto in subjectum, 240 ; knowl- 
edge of, does not depend on " imagi- 
nation," 273. 

Figures, in logic, 560; principal one, 
407; less principal ones, 407; in- 
direct or fourth, 407. 

Fingers, counting on, 482, 562. 

Finite, the concept of, how arrived at, 
12. 

Finnish, 297. 

Fire, not known by Marian Islanders, 
104; its intimate nature more than 
probable, 549, 552. 

Flacius, 295. 

Fliegende Gedanken, 182. 

Florileges, 548. 

Fludd, Robert, his " Philosophia Mo- 
saica," 63. 

Fluid, perfect, of Cartesian, impossi- 
ble, 126. 

Fluidity, in all bodies, 126. 

Fontenelle, on plurality of worlds, 550. 

Force, 174 ; as active power, 174. 

Form, of Man, not enough to consti- 
tute man, 244; of words, what? 
304, 305 ; arguments in, what ? 559. 

Forms, substantial, term inaptly em- 
ployed by scholastics, 347, 380 ; Des- 
cartes on, 348. 

" Formalities," 569. 

Formido oppositi or scrupulousness, 
210. 

" Forty-Seventh " proposition, its dem- 
onstration, how dependent on formal 
logic, 565. 

Foucher, Abbe', 420. 

Fractions, their reduction to lowest 
terms, 426. 

Fractive faculty in grain-mill, 63. 

Frauds, pious, sometimes more effec- 
tive than truth badly managed, 198 ; 
to be avoided, 606. 



Free, when a man is, 179; a man 
awake is not, as to thinking, 181 ; 
is, as to transference of his thoughts, 
181 ; man is not, in certain circum- 
stances to certain ideas, 181 ; and 
voluntary, term illustrated, 181 ; act, 
in, what sense necessary, 183 ; beings 
do not act indeterminately, 183. 

Freedom, term ambiguous, 179; of 
right, 179 ; of fact, 179 ; in its gen- 
eral sense, 179; in its particular 
sense, 179 ; why a ball in motion not 
an instance of, 180 ; properly cannot 
belong to will, 184; of equilibrium 
impossible, 184 ; what understood by 
term, 184 ; without understanding, of 
no use, 216. 

Freedom of Will, opposed to internal 
restraint, 179; opposed to restraint 
of necessity, 179; what it consists 
in, 180, 202 ; not placed in a perfect 
indifference or equilibrium, 203, 204 ; 
does not throw off yoke of reason, 
206; consistent with determination 
of will, 206 ; founded in real happi- 
ness, 206. 

Fre'nicle, M., 393. 

Fromondus, 234. 

Future life, how most men regard it, 
196; its influence on choice, 208; 
grounds on which wicked deem it 
impossible, 217; favorable conject- 
ures concerning, 217 ; certitude of, 
218 ; definition of, 246 ; its influence 
on practice of virtue, 495, 496. 

Galen, 407. 

Galileo, on great antiquity of sun, 
237; his condemnation considered, 
613. 

Gallic, language, 296. 

Gallican confession, 612. 

Gallows, a use of, 92. 

Gassendi, 62, 64, 66. 

Gaudium and Isetitia compared, 172. 

Gender, of no account in philosophical 
grammar, 365. 

Genealogical tree, to illustrate rela- 
tions, 236. 

General notions, 43; origin of, 71; 
signs used by men deprived of 
speech, 145; truths (propositions, 



790 



LEIBNITZ'S CRITIQUE OF LOCKE 



maxims), their universality not 
proved by examples, 43; do not 
come to us from the senses, 70 ; we 
find them, do not form them, 70, 
325; the senses give us occasion to 
perceive them, 70; recognized as 
soon as heard, 73 ; employed , though 
not distinctly, in thought, 73; as 
little in thought in reasoning as 
muscles in thought in walking, 71 ; 
not easily represented distinctly, 74 ; 
why not, though innate, most vivid 
in minds of children, idiots, and 
savages ? 85 ; their usefulness, 307 ; 
how their truths may be deter- 
mined, 454; can they be applied to 
substances? 454-456. 

Generality, its reality discussed, 313. 

Genii, always joined to body, 52, 334; 
their powers of perception, 228; 
their alleged employment in future 
ages, 551 ; are they animals more 
perfect than we ? 574 ; there is much 
they do not know, 574 ; are in infi- 
nite gradation, 575. 

Genus, physical and logical distin- 
guished, 58; logical may exist be- 
tween heterogeneous things, 58 ; 
its genealogy, 59; definition of, in 
what case not provisional but per- 
fected, 456, 457. 

Genus, and species, how they origi- 
nate, 310 ; classification into, too 
little esteemed, 311 ; and difference, 
interchangeable, 313. 

Geometry, employs pure reason, 22; 
declines experience, 22 ; its proposi- 
tions innate, 76 ; in us virtually, 78 ; 
can be prosecuted apart from sight 
or touch, 78; mind awakened to by 
touch, 78 ; its demonstrations would 
be disputed if, like ethics, it op- 
posed our passions, 93 ; no exact cat- 
alogue of its axioms, 95 ; can be 
learned by blind and paralytic, 139 ; 
built on general axioms, 473; of 
Greeks, 523; of Egyptians, 523; of 
Chinese, 523 ; if follow senses in, fall 
into error, 523 ; asymptotes in, 523 ; 
permits us a glimpse of eternal truth, 
523; ancient, the system described, 
524. 



Gerhardt, his introduction to the 
JVouveaux Essais, 3-12; his esti- 
mate of Leibnitz's Meditationes de 
Cogitatione,Veritate et Ideis, 3. 

Gerontophony, 222; name of, if be- 
stowed, would not give a new idea, 
222. 

Gesner, his Pandects, 626. 

Gideon, 37. 

Gobien, Father, 104. 

God, apparent absence of idea of, 
means only absence of occasion to 
awaken it, 21; inclination to idea 
of, from nature of soul, 72 ; penetra- 
tion of space possible to, 83; his 
existence binds us to observance of 
most moral precepts, 94; idea of, 
innate, 94, 234, 493, 499; are there 
nations which have no idea of? 
Fabricius's denial, 102, 103; Locke 
quoted on idea of, 103, 104 ; Locke, 
in his description of the idea of, 
approaches innate truths, 104; is 
actus purus, 113; the ground of 
eternal truths, 153; the place of 
things, 153; not extended, 159; im- 
mensity of, 159; by his essence, 
source of possibilities, 159 ; by bis 
will, source of actualities, 159; the 
principle of beings, 163; chooses 
freely, yet is determined in choice, 
183 ; continually produces, 230 ; fills 
the universe, 230 ; in social connec- 
tion with us, 247 ; and created spirits, 
difference between, 332; extra- vel 
supra-mundana intelligentia, 382; 
the supreme substance, 430 ; his pure 
and universal act essential to all 
changes in matter, 430 ; his existence 
demonstrable, 469, 499, 500; wit- 
ness to his existence, in our con- 
stitution, 499 ; impressions on the 
soul which indicate, 499 ; evidence of 
his existence, according to Locke, 
equals mathematical demonstra- 
tions, 499 ; evidence of existence of, 
arises from reflection on ourselves 
and our own indubitable existence, 
500. 

God, existence of, Anselmic argument 
for, misunderstood by scholastics, 
502-504 ; imperfect but not a paralo- 



INDEX A 



791 



gism, 504; morally demonstrable, 
504; Descartes' argument for, from 
" idea of Him in the soul," 504, 505 ; 
his argument for, involves an un- 
proved assumption : that we have the 
" idea," and that it comes from the 
original, 505 ; proved by Pre-estab- 
lished Harmony, 505 ; nearly all ar- 
guments to prove, good, but must be 
perfected, 505. 

God, as Thinking Being, cannot be 
material, since infinite and eternal, 
'508; absurd if all matter thinks, 
508 ; absurd if part of matter thinks, 
508 ; cannot be a mass of unthinking 
matter, 509 ; cannot be matter in 
motion, 509; cannot be matter at 
rest, 509; possible to attain a con- 
ception of how, made matter, 509 ; 
how he gives existence to, spirit is 
more difficult to understand, 509; 
his existence only has a necessary 
connection with ours, 511. 

Godwin, Franc, on the moon, 551. 

Gold, result of its artificial production 
if possible, 340; if a body had all the 
qualities of, without malleability, 
what then? 357; on the determina- 
tion of its inner constitution, 393. 

"Gold, all, is fixed" is an identical 
proposition, 340; is it intelligible? 
340 ; not known by agreement or dis- 
agreement of ideas, 460 ; can we cer- 
tainly know this for a truth, and 
why? 460,461. 

Golden Rule, 88. 

Golius, his theory on Chinese language, 
287. 

Gonzales, traveller to the moon, 342. 

Goropize, what? 303. 

Goropius, Becanus, his ridiculous ety- 
mologies, 303; claims that German 
can contest honor of being primitive 
language with Hebrew, 303. 

Good, what, 167, 200, 202 ; its division, 
167 ; when is one in possession of a, 
172 ; how it may become an evil, 
202; how to be utilized, 207; moral, 
260 ; moral, not an arbitrary institu- 
tion, 261 ; moral, conformed to nature 
or reason, 261; moral, founded in 
God's rule of reason, 261 ; moral, not 



dependent on legislation, 261; phys- 
ical, what? 261. 

Goodwill, men of, 608. 

Goose, Mother, the transformation in, 
245. 

Government, its claim on the absolute 
freedom of its citizens, 433. 

Grace, defined, 377. 

Gradations in nature, 549. 

Gratitude, an act of justice, 497; 
foundation of Actio ingrati, 497. 

Gravitation, 59. 

Greaves, his theory as to the pyramids 
of Egypt, 150. 

Greeks, as geometers, 22 ; their admi- 
rable style in mathematical compo- 
sition, 416. 

Green, its definition and analysis, 120, 
320, 458. 

Gretser, his "Analysis of Faith," 618; 
believes that a new article of faith 
may be made through continuous 
presence of the Spirit, 618. 

Grimaldi, 394. 

Grotius, Hugo, 494, 542. 

" Ground, the, is everywhere the 
same," a fundamental principle, 
575. 

Guericke, 127, 153. 

Guerre, the personator, 310. 

Guilt connected with inability, 564. 

Habit, what ? 223. 

Habitus intellectuales , on these depend 
the sects in philosophy, 30 ; formed 
through Association of Ideas, 30, 31. 

Hans Kalb, and his reputed calf's 
head, 352. 

Happiness, never consists in complete 
possession, 194 ; and joy, 195 ; is op- 
posite extreme to misery, 200 ; is the 
utmost pleasure of which we are 
capable, 200; its lowest degree, 200; 
is lasting pleasure, 200, 207; in- 
volves progression, 200, 201 ; un- 
equal in different persons, 200, 201 ; 
a "road through pleasures," 200; 
reason will carry to, 200 ; shortest 
way to, may not be best, 201 ; search 
after, man's perfection, 206; dis- 
tinction between real and imaginary, 
206 ; requires not so much knowledge 



792 



LEIBNITZ'S CRITIQUE OF LOCKE 



as good will, 215; within reach of 
idiot, 216. 

Hardness, what? 125; conceived by 
reason, 126 ; terms preferred to that 
of, 126. 

Hardy, Leibnitz's discussion with, 
465; believed the demonstration of 
Serenus paralogistic, 465 ; com- 
mended by Descartes, 466. 

Harlequin's stripping, an illustration 
from, 362 ; in moon, 551. 

Harmony, Pre-established, 11, 66, 334, 
430, 553. 

Hatred, what? 167, 173. 

Health, its neglect commented on, 610. 

Heap of thirty-six stones, illustration 
from, 269. 

Heat, relative to suitable organs, 133, 
134 ; why sensation of, varies, 134 ; 
wrongly said not to be in sun, 134, 
135. 

Heathen, salvation of, 594, 595; ac- 
cording to Romish doctors, 594. 

Hebrew particle, a, has fifty significa- 
tions, 365. 

Heliogabalus, if his soul is in the hog, 
what is the hog? 241. 

Hell fire burns up souls ? 428, 429. 

Helmont, Van, 67. 

Helmstadt, 581. 

Herbert, Lord, his catalogue of innate 
principles, 95. 

Hercules, as the figure of, in rude mar- 
ble outlined by veins, so idea in 
mind, 3, 46 ; known by gait, 357. 

Herlinus, editor of Euclid, 404. 

Herodotus, his one-eyed nation, 389; 
disagrees with Ctesias, 545 ; accords 
with Old Testament, 547. 

Herostratus, a hero with some, 536. 

Hippocrates, the physician, 48, 476; 
the geometer, 527. 

Historica, Be fide, of jurisconsults, 545. 

Historical doubts, 545. 

History, satire in, 542 ; romance to be 
expelled from, 542; details in, un- 
certain, 543; battles of, imperfectly 
described, 543 ; writers of, posterior 
to events they describe, worthy of 
attention, 544; its value, 544, 545; 
the private, of a people, when of 
much value, 545 ; the fabulous in 



history, 546 ; when stories of differ- 
ent and far-separated people agree, 
it is a sign of truth in them, 546; 
value of medals, inscriptions, etc., 
in, 547 ; of China much to be de- 
sired, 547 ; principal uses of, 547 ; of 
clothing, valuable, 547; as a diver- 
sion, allowable, 548; ought to be 
instructive, 548. 

Hobbes, 450 ; writes against mathema- 
ticians, 93 ; afraid of ghosts, 283. 

Hofmann, Daniel, 581. 

Holden, Henry, his "Analysis of 
Faith," 617. 

Homicide, 385; as murder, 385; as 
manslaughter, 385; chance-medley, 
385. 

Honor, as a principle of action, 536. 

Honorius and his hen, 610. 

Hooker, " the judicious," 566, 567, 570. 

Hope, what? 172. 

Horace, 328, 335, 566. 

Horodeictic faculty in watches, 63. 

Horses, Welsh and Flemish, 237 ; with 
genealogical trees, 259. 

Horseshoe, iron, when converted by a 
certain spring into copper, changes 
as individual, 240. 

Hottentots, name for Holy Spirit 
among, 103, 290. 

"Houses, dwellers in small," we can- 
not expect much search after truth 
among, 608, 609. 

"Hundred Horses," an illustration, 
617. 

Hunger, as an illustration of mental 
perception, 119. 

Huygens, 150; gives up 'vacuum,' 16; 
on logic in mathematics, 18; on 
planetary men, 343; "De Alea," 
539; his " Cosmotheoros," 550; his 
view regarding other planets, 550 ; 
his use of analogy, 550. 

Hybrida conclusio, 84. 

Hybrids, do they multiply? 345. 

Hypothesis, how proved, 520, 521 ; 
must be combined with experimen- 
tation, 526; may lead to new dis- 
coveries, 526 ; is a help to memory, 
526; must not be hastily framed, 
526; greatly shortens the road to 
discovery, 526; physical, cannot be 



demonstrated, 565 ; zeal for, what? 
613; variable, 613; source of love 
for, 614. 
Hysteron proteron (le rebours), not 
arguing in a circle, 409. 

" I and He " without parts, 247. 

"I exist" carries with it highest evi- 
dence, 469. 

"I think, therefore I am," not an 
axiom, 469; a truth of fact, 469; 
does not prove existence by thought, 
469. 

"I" and "existence" only God un- 
derstands how they are united, 
469. 

Icarus, 442. 

Ice and the King of Siam, 530. 

Ideas adsequat.se, what? 17, 278; pro- 
prise, 3 ; what ? 3 ; necessity of hav- 
ing, 3 ; how in mind, 3. 

Idea and image, confounded by Locke, 
273 ; in a chiliagon, former possible 
but not latter, 273 ; how they differ, 
274. 

Ideal world, 326. 

Ideas, association of, 281; instances 
of, 282, 283. 

Ideas, when true and real, 14; the 
origin of, not preliminary in philoso- 
phy, 15 ; come from within the soul, 
15; when doubtful, 15; when chi- 
merical, 15 ; their possibility proved 
a priori, 15 ; their possibility proved 
a posteriori, 15 ; primitive or deriva- 
tive, 21; in what sense both sorts in 
us, 21; defined, 21, 109; in what 
sense can subsist unperceived, 21 ; 
innate, what? 22; and truths, how 
related, 22 ; Locke's two sources for, 
23; implanted, of Plato, 38; if they 
come from without, then we should 
be outside ourselves, 76; pure, op- 
posed to ' phantoms ' of sense, 78 ; 
which do not come from sense, ad- 
mitted by Locke, 82 ; of sense con- 
fused, as also the truths founded on 
them, 82 ; of intellect are distinct, as 
are also the truths founded on them, 
82 ; difficulties in, depend on amount 
of attention required, 82; in mind 
as habitudes, aptitudes, dispositions, 



105 ; distinct, represent God, 109 ; 
confused, the universe, 109; imme- 
diate, internal objects of thought, 
109; not forms of thought, 109; 
their perception, not themselves, 
come through sensation and experi- 
ence, 111; pure and distinct, inde- 
pendent of the senses, 119; distin- 
guished from thoughts, 119 ; which 
come to us by one sense only, 121, 
122 ; supposed to come to us by dif- 
ferent senses enumerated, 129 ; sup- 
posed to come by sensation and 
reflection enumerated, 130; their 
simplicity disputed, 130 ; their cause : 
are they arbitrary, or have they an 
expressive resemblance? 133; and 
the secondary qualities which pro- 
duce them, their relations discussed, 
133; resemble both primary and 
secondary qualities, 133; resemble 
motions which cause them, 134 ; from 
sensations often unconsciously al- 
tered by mental judgment, 136 ; are 
modes of thought, 143 ; internal ob- 
jects, 143; do not cease when not 
matters of consciousness, 143; and 
'bodily movements' 'correspond,' 
181 ; and ' movements,' there is an 
order and connection in, 181 ; or 
notions, three degrees of, 217 ; ob- 
jects of, proposed classification of, 
221; simple, those most modified, 
223; collective, of substances, 234; 
often applied by Locke to the objec- 
tive realities which the ideas repre- 
sent, 237; clearness and obscurity 
of, 265; when distinct, 2C6, 267; 
when confused, 267; confusion in, 
when blamable, 267; confusion of, 
sometimes lies in the composition, 
269; sometimes in the bad use of 
names, 269; sometimes in defective 
analysis, 269; avoided to some ex- 
tent by precision in names, 271; 
real,' 275; fantastical, 275; not 
necessarily conformed to their foun- 
dations in nature, 275 ; the erro- 
neous opinion regarding, that God 
has arbitrarily assigned them to 
mark qualities, 276 ; association of, 
281; privative, why should there 



794 



LEIBNITZ'S CRITIQUE OF LOCKE 



not be ? 289 ; natural order of, 289 ; 
same for all intelligences, 289 ; sub- 
stances and modes represented by, 
306; of substances and sensible 
qualities more fixed, 306 ; reflective, 
enter into tbose of tbings, 306; 
bow tbey become general, 307 ; ab- 
stract, may be attributed to one 
another, 313, 497 ; simple, and of sub- 
stance, their reality not necessary, 
318 ; God has, and can communicate 
them before creating their objects, 
318; cannot demonstrate that ob- 
jects of, are without us, 319 ; simple, 
can have real definition, 320; express 
only possibilities, 325; are they arbi- 
trary? 325; are in God eternally, 
325 ; are in us before thought, 325 ; 
not to be taken as actual thoughts 
of men, 325, 326 ; influence of names 
on, 328; physical, what regulates 
their combination, 353, 354 ; generic, 
do not follow models set in nature, 
355 ; agreement or disagreement of, 
four kinds according to Locke, 
400; that of identity or diversity, 
400; that of relation, 400; that of 
coexistence, 400; that of real ex- 
istence, 400; Locke's four kinds 
reduced to two, 401 ; that of com- 
parison, 400, 401; that of concur- 
rence, 401 ; concurrence includes 
coexistence and existence, 401 ; want 
of, 439; of substances have neces- 
sary conformity to eternal arche- 
type, 446 ; what meant when said to 
be true or false ? 452; general, may 
be broken up ecthetically into par- 
ticular propositions, 464, 465 ; super- 
fluous expressions of, 483; we may 
not have real, yet know what we 
are saying, 505; may be in us not 
consciously, but availably, 505; do 
not prove existence, 511 ; distinct, 
our knowledge of, defective, 570; 
their multitude perplexing, 570 ; not 
enough for reasoning, 570 ; confused, 
many lacking to men, 570 ; are 
' images ' or ' impressions,' 570 ; give 
rise to instincts, 570. 
Ideas, complex, of three kinds, 5 ; 
when clear, 266; their obscurity 



rests on more than names, 268 ; 
may rest on presence in them of 
ideas too few or too confused, 268; 
may be clear and yet obscure, 272 ; 
something volitional in formation of, 
276 ; how to avoid mistakes in form- 
ing, 276; of substance, when real, 
277 ; of substance, when fantastical, 
277 ; are not entirely without arche- 
type, 280; the combination of, not 
wholly voluntary, 280 ; of a triangle 
give a perfect idea, 280 ; which enter 
iuto courage, 280 ; can they be com- 
posed of different simple ideas in 
different minds, 313; can they be 
regarded as arbitrary in formation, 
325, 326 ; are they made by mind or 
have they archetypes in eternal pos- 
sibility of things, 446. 

Ideas, derivative, 21 ; are formed, 
21. 

Ideas, innate, what? 4, 21; denied by 
Locke, 4; at foundation of meta- 
physics and ethics, 11 ; the propo- 
sitions of arithmetic and geometry 
are, 76. 

Ideas, primitive, what? 15; distin- 
guished, 21; their reduction, 220; 
some susceptible of further reduc- 
tion, 220; how they may be ar- 
ranged, 220. 

Ideas, real : not necessarily conformed 
to their foundations in nature, 275 ; 
when possible, 275; simple ideas 
are, 275 ; when complete, 278 ; when 
incomplete, 278; simple complete, 
278 ; adequate and inadequate, 278, 
279; imperfect, give rise to many 
and at present independent defini- 
tions, 279 ; of geometry, give per- 
fect ideas, 279. 

Ideas, sinrple, 4; rudiments of knowl- 
edge, 119; which come to us by 
one sense, 121 ; which come to us by 
different senses, 129; those most 
modified, 223; when clear, 265, 266; 
all real, 275 ; mind passive in regard 
to, 276 ; mind active in separating 
them for consideration, 276 ; simple 
only as regards us, 322 ; have little 
subordination in line of predication 
because of our ignorance, 323 ; only 



INDEX A 



in appearance, 323 ; our uncertainty 
as to their incompatibility, 446. 

Identical, propositions, not to be 
despised, IS; maxim, the general, 
83; propositions employed in logic, 
406; affirmations, their use exhib- 
ited in logical conversion, 409. 

Identity, axiom of, a first principle, 13, 
100; did it persist under the forms 
of Euphorbus, the cock and Pythag- 
oras, in which forms the soul of 
Pythagoras had been ? 21, 100 ; not 
dependent on memory, 114 ; depends 
on fact that future in each substance 
is united to past, 115 ; or Diversity, 
what is it ? 238 ; Locke's definition 
of, 240; organization by itself not 
enough for, 240; configuration by 
itself not enough for, 240; the 
monad essential to, 240; not in 
bodies, 240 ; but in substance, 241 ; 
in plants and animals it is depend- 
ent on souls 241 ; depends on soul or 
spirit which constitutes the Ego in 
thinking beings, 241, 242; depends 
on vital union of body with soul, 
241; not on fluent body, 242; not 
upon certain atoms, 242 ; maintained 
only by conservation of same soul, 
242 ; is it affected by metempsychosis 
of Pythagoras? 243; depends on 
memory, 243; physical and real, 
243, 246; moral and personal, 243, 
245 ; founded on consciousness, 245 ; 
something more than a mere pres- 
ervation of, needful to be called 
"man," 245; apparent, to be distin- 
guished from real, 246; moral, con- 
stitutes a person capable of rewards 
or punishments, 246; apparent im- 
plies real, 246; does not depend on 
unbroken memories, 246, 247 ; pre- 
served by a middle bond of con- 
sciousness, 246; personal, proved 
with utmost certainty by present 
reflection, 247 ; personal, proved for 
ordinary purposes by memory dur- 
ing interval, or testimony of others, 
247; personal, absolutely dependent 
on real identity, 247 ; personal, not 
solely dependent on consciousness, 
247 ; personal, rests on phenomenon 



of self, 247; physical, rests on self, 
247 ; can a breach of, occur in con- 
sciousness of same immaterial sub- 
stance ? 248 ; real, depends on bond 
of perceptions, 250; moral, depends 
on bond of apperceptions, 250. 

Idiots, their defects, 146; compared 
with madmen, 146; compared with 
stupid persons, 146 ; imaginative 
and well read, arrogate inspiration, 
599. 

Idol, the, of the day, always the great- 
est saint of paradise, 211. 

Ignorance, falsely praised by some, 
85 ; not always affected, 214 ; a 
cause of false judgment, 214; a 
knowledge of, desirable, 439; its 
three principal causes, 439 ; a first 
cause of, want of ideas, 439; a sec- 
ond cause of, inability to discover 
connection between ideas, 439; a 
third cause of, we do not follow the 
ideas we have, 441 ; a despair of dis- 
tinct explanation favors continuance 
of, 442 ; bad use of terms has helped 
to maintain, 443; how a sin, 615. 

Ilargus, its derivation, 302. 

Illustrations, value of, 394. 

Image, and idea, how they differ, 274 ; 
clear, may consist with a confused 
idea, 274. 

Images, what? 182; come to us, 182; 
not controllable, 182; distinguished 
from exact ideas, 182; may arrest 
182. 

Imagination, 144, 145; not needful to 
number or figure, 273. 

Imagines majorum, 259. 

Imbeciles, why regarded as men, 342. 

Immediate truths, what? 499. 

Immortality, not a miraculous grace 
from God, 53; of human soul dis- 
tinguished from incessability of ani- 
mal soul, 245 ; of human soul, 245, 
246. 

Impact of bodies, of the motion aris- 
ing from, 175, 176. 

Impenetrability of bodies, 83 ; perfect, 
125, 127. 

Imperceptible bodies, 112. 

Impetuosity of bodies, 123. 

Impudence, 223. 



790 



LEIBNITZ'S CRITIQUE OF LOCKE 



Impulsions between parts of matter, 
differing views of, 54, 55. 

Inability in some cases consistent with 
guilt, 564. 

Inattention, a cause of false judgment, 
214. 

Incessability of animal soul, 245, 246. 

Inclination, how it passes into a prac- 
tical truth, 87. 

Inclinations or propensions, how 
formed, 201; various kinds, 201; 
originate in soul, 202 ; beginning of 
desire, 202 ; combated by contrary 
inclinations, 203; combated by oc- 
cupations of another nature, 203. 

" Incorporeal things," 329. 

Index, an, in geometry, 625; its plan, 
625; its use, 625; to science as a 
whole, 625 ; to science as a whole 
might be systematic, 625 ; to science 
as a whole might be alphabetic, 625. 

Indian, philosopher, his theory of how 
the earth is supported, 226, 227. 

Indices, ad torturam, 539; ad terren- 
dum, 539; ad capturam, 539; ad 
inquirendum, 539. 

Indifference of will not essential to 
freedom of will, 203, 204 ; not possi- 
ble, 171, 204 ; whence notion of, 205 ; 
an absolute, an imperfection, 204, 
205 ; the alleged, only apparent, 205 ; 
dependent on a small prevalence, 
205; is really only a capability of 
being determined by least sensible 
subjects, 205. 

Individual, precise idea of, difficult to 
discern, 310 ; absence of precise idea 
of, shown in deception by persona- 
tion, 310; mathematical, 335, 336; 
physical, 336. 

Individuals, knowledge of, impossible, 
309; something essential to, 331 ; of 
one species never alike, 332. 

Individual (proper) names; usually 
given to ideas of substances, 361 ; 
given occasionally to an accident, 
361. 

Individuality, includes infinity, 309. 

Individuation, principle of, 239. 

Inertia, 123. 

Infants, why regarded as men, 314, 
342, 350, 448 ; damnation of, held by 



Augustine, rejected by the Scholas- 
tics, 594. 

Infer, to, illustrated, 557. 

Inference, 555. 

Infinite, the, according to Locke, 12 ; 
according to Leibnitz, 12; as posi- 
tive, 17; as composite, denied, 17; 
not applicable to a whole, 154, 162, 
163, 164 ; is it a mode or quantity ? 
161; the number of things is, 161; 
a number never is, 161, 163; syn- 
categorematic, what ? 161 ; exists 
only in the absolute, 162; idea of, 
how applied to God, 162; not neces- 
sarily suggested by magnitude, 162; 
not a modification, 162 ; arises from 
consideration of similarity or the 
same ratio, 162 ; completion of idea 
of, comes from ourselves, 163 ; 
source of notion, 163, 164; in in- 
tention, 163 ; in extension, 163 ; can 
only be thought into original quali- 
ties, 163; space, no idea of, 163; 
duration, in what sense a positive 
idea of, possible, 164; divisibility, 
gives no image, but an idea, 234, 275. 

Infinites, our relation to, 51. 

Infinitesimal, parts used only by ge- 
ometers 163 ; analysis (calculus) 
unites geometry with physics, 440; 
discovered by Leibnitz, 573 ; relieves 
imagination, 574; is superior to ge- 
ometry of Descartes, 574. 

Inhesion, 62. 

"Injustice, there is none where there 
is no property," discussed, 433. 

Innate ideas, truths, principles, max- 
ims, not to be used as a cloak for 
idleness, 13, 72, 99; perceived less 
easily than acquired or recollected, 
20; difficulty in their perceptions 
does not prove their non-existence, 
20 ; occasions cause them to be seen, 
do not bring them into being, 20; 
defined, 21, 22, 74; not proved en- 
tirely by universal consent, 23, 71 ; 
not proved by approval on presenta- 
tion, 23; sensations reminders of, 
38; proof of, on internal grounds, 
38; Locke repudiates, 38; none, 65; 
not needed, 70; why Locke opposed 
them, 71; often prejudices, 71; not 



INDEX A 



797 



alone those confusedly known by 
instinct, 74 ; truths are, yet we learn 
them, 75; often suppressed as pre- 
mise in enthymeme, 77 ; external 
"doctrine " stirs them up, 77 ; a con- 
sent among men sufficiently general 
an " indication," not a demonstra- 
tion of, 77; their certitude comes 
from what is in us, 77 ; are employed 
without express consideration, 77 ; if 
not known, do not cease to he innate, 
77 ; recognized as soon as heard, 77 ; 
at bottom known by all, 77 ; senses 
not sufficient to show their necessity, 
81 ; give the occasion and attention 
required for their discovery, 81 ; 
contain some of which we have not 
thought and some of which we will 
never think, 84; appear through 
attention, 85 ; some, are not part of 
natural light, 86; derivative truths 
are, 88; formed by insight and in- 
stinct, 88. 

Innate, practical principles, how ad- 
mitted by Locke, 87 ; principles and 
innate truths distinguished, 88 ; prin- 
ciples, some moral rules are not, and 
yet are innate truths, 88; compre- 
hend instinct, and natural light, 88, 
92 ; distinguished from natural light 
as genus from species, 92 ; that men 
violate the limits of justice no proof 
that they are not, 92, 93; truth, not 
known always and by all, 93 ; viola- 
tions of moral law, do not disprove 
that it is, 93; ideas, are not at first 
known clearly and distinctly as such, 
94; require attention and method, 
94; all not indubitably evident at 
first, 94; can be asserted only of 
necessary truths and instincts, 95; 
influence of education on, 98; may 
be obscured but not effaced, 98. 

Innate truths, in what sense difficult 
and profound sciences are, 76; dis- 
tinguish us from beasts, 77 ; can 
both be known and also found by 
mind, 80; principles and innate 
truths distinguished, 88; idea of 
God among, 94; idea of future life 
among, 94 ; doctrine of, may lead to 
assumption of infallibility, 96 ; uni- 



versal consent to, not principal but 
confirmatory proof , 96 ; can tfiey be 
effaced by education or custom ? 98 ; 
why not more lustrous in children 
and illiterates than in adults and 
literati ? 98 ; may be obscured but 
not effaced, 98; not creatures of 
prejudice, 98; reduce to first prin- 
ciples, 99; "it is impossible for a 
thing to be and not to be; " is this 
among? 100; 'impossibility' and 
'identity' among, 100; 'being,' 
' possibility, and ' identity ' among, 
100; ' whole is greater than its part,' 
Locke denies its place among, 102 ; 
' God should be worshipped ' among, 
102 ; idea of virtue among, 104 ; are 
they in mind as memories? 105 ; 
defined, 105 ; may lead to laziness, 
107 ; unravelled by discernment, 143. 

Innocent, 262. 

Innocents, 448. 

Innovation, must guard against ambi- 
tion to make, 99. 

Insensibilia corpora, 3; ingredientia 
perceptionum confusarum, 3. 

Insensible perception, basis of relation 
between sensible qualities, 50. 

Instant, defined, 155. 

Instinct, in ethics, 86; not always 
practical, 87; its principles become 
conclusions of natural light, 88 ; 
its principles proved by reason, 88; 
{le naturel) inclines custom to good 
side, 90 ; establishes tradition of ex- 
istence of God, 90 ; gives affectionate 
feeling between members of species, 
90, 91 ; what ? 391 ; even in man, 391. 

Instincts, sometimes hard to distin- 
guish from customs, 96; their rea- 
son unknown, 99 ; reasons of, to be 
sought, 107. 

Intellection, what? 178. 

" Intellectual System of Universe," 65. 

Intention, 163. 

Intentional species, 55, 381. 

Interjection, says all in a word, 368. 

Intuition, a certain knowledge by, 404 ; 
primitive truths known by, 404. 

Invention, 556. 

Invenzione la piii vaga, employed in 
the spiritual world, 335. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Invisible movement, 112. 
Involuntary, denned, 177. 
Io ti vedo, addressed by Italian to gal- 
lows, 92. 
Irish, 296. 
Isogon is in rectangle, 568. 

John, St., fecit aurum, 603. 

" Journaux des Savans," 66, 421. 

Joy defined, 171, 172 ; and felicity, 87; 

and sadness, arise from prevalence 

of pleasure or pain, 211. 
Judgment, what? 143; distinguished 

from mind, 144; false, 209; reasons 

of, 214; Day of, 254. 
Jure suo, qui utitur, nemini facit in- 

juriam, 492. 
Jurisconsults, bonmot of, 91 ; a rule of, 

492 ; juramenta of, 538. 
Jus accrescendi, 434. 
Juvenal quoted, 91. 

Kepler, 123, 551. 

Kerkring, 345. 

Knowledge, our present, best, 227, 228 ; 
can go on to infinite, 228 ; of body, a 
perfect, perhaps possible, 228 ; em- 
pirical, how useful, 273; of truth, 
what? 397, 400; a particular signifi- 
cation of, 397; a general significa- 
tion of, 397, 398 ; confused perception 
in empirical, 400; of hypothetical 
truths, ideas in, 400; of truth, its 
content, 400, 401; as actual and 
habitual, 401 ; habitual, its employ- 
ment and improvement, 401, 402; 
two sorts of, suggested, 402; intui- 
tive, 404, 410 ; demonstrative, what? 
411 ; opinion, perhaps not, 417 ; sen- 
sitive, 417, 419; sensitive, its certi- 
tude, 420; certain, 420; probable, 
420; clearness of, related to clear- 
ness of ideas, 423; extent of, 423; 
not always intuitive, 423 ; not always 
demonstrative, 423 ; sensitive, lim- 
ited, 423; sensitive, more limited 
than ideas, 423 ; sensitive, can be ex- 
tended, 423, 424; in confused ideas, 
424 ; its limits presented, 432 ; of real 
existence, 439 ; difficulties in the way 
of, 439, 440; of bodies and spirits, 
441 ; have ideas for, 441 ; lack facts 
for, 441 ; lack acuteness of senses 



for, 441 ; though concerned entirely 
with ideas may have certainty, 445 ; 
certainty of, suggested criteria of, 
445; mathematical, real though 
founded on ideas, 446; is of gen- 
eral or particular truths, 452; of 
general truths best conceived by 
help of words, 452; certainty of, 
454; when self-evident, 464; order 
of, 469; particular, or of facts dis- 
tinguished from universal and neces- 
sary, 470 ; appellations of, possibility 
of their extension, 513 ; commences 
in particular propositions ? 517 ; em- 
ployment of mnemonic maxims in, 
517 ; mnemonic maxims not formed 
by induction, 518; what conduces to 
the extension of, 527 ; mediate ideas, 
their place in, 527; neither wholly 
necessary, nor wholly voluntary, 
528; divine, intuitive, 574; angelic 
and beatified, 574. 

koivo.1 evvoiai, 43, 71. 

Koran, 90, 

Kuhlmann, Querin, 601; on the Trin- 
ity, 601. 

" L " employed to signify gentle move- 
ment, 300. 

Labadists, 602. 

Labbe, Father, his language, 293. 

"Labyrinth, sive cle compositione con- 
tinui," 234. 

Lsetitia and gaudium compared, 172. 

Language, Locke on, 5; tropical use 
of, must be guarded, 271, 272; origi- 
nates in desire of being understood, 
287; serves in reasoning, 287; of 
tones, 287 ; place' of general terms 
in, 288; study of, reveals, not the 
origin of ideas, but the history of 
their discovery, 289; primitive root 
of, 297 ; German likely the primi- 
tive? 298. 

Languages, have altered, 294; have 
common roots, 297; Keltic, Latin, 
and Greek, have common origin, 
297 ; a primitive element in all, 298; 
show the origin and migration of 
nations, 303, 304; best mirrors of 
human mind, 368 ; practical but not 
precise, 370; same terms in, may 



799 



convey different ideas, 371 ; of world 
will finally be reduced to grammar 
and dictionary, 372; will be better 
known with increase of knowledge 
of mind, 372. 

Lateran Council, 581. 

Law of continuity, 50. 

Law, divine, 262; natural, 262, 487; 
positive, 262. 

Law, civil, 262; of reputation, improp- 
erly so called, 262 ; described, 264 ; its 
reformation needed, 264, 265; a pre- 
cept of wisdom or of the science of 
happiness, 391. 

Laws, three sorts, according to Locke, 
261. 

Leander and Hero, 211. 

Leaves, no two alike, 240. 

Leeuwenhock, 346. 

Legislator, not implied in all natural 
rewards and punishments, 94. 

Leibnitz, his sketch of Locke's Essay 
in " Monatliche Auszug," 7; hints 
at a more complete reply, 7 ; delays 
therein, 8; was to be in form of 
dialogue, 9; unfinished, 9; his esti- 
mate of Locke's Essay, 10, 13 ; turns 
to Theodicee, 10 ; Raspe publishes 
reply, 10; differs from Locke as 
Plato from Aristotle, 10 ; thinks soul 
not a "tabula rasa," but that it 
has principles, 11 ; truth has other 
foundations than experience, 11 ; 
credits Locke with an approach to 
his views, 11, 45; regards bodies as 
always in motion, 11 ; on axioms, 
12 ; on logic, 12; on nominal and real 
being, 12; on the Infinite, 12; his 
explanation of Locke's aversion to 
the doctrine that principles are born 
with us, 13; his first principles, 13; 
differs from Locke on the soul ever 
thinking, 16; how he differentiates 
his system from that of Locke, 42 ; 
on German philology, 304. 

Leibnitz's system, gives a new aspect 
to interior of things, 66; unites 
different schools, 66; explains union 
of soul and body, 66; gives true 
principle of things, 66; is simple, 
66; is uniform, 66; explains laws of 
nature, 66; how characterized, 68. 



Leine, the river, whence its name, 300, 
308. 

Leipsic Acts, 266. 

Lemma, what ? 413. 

Lemnius, Levinus, his monster, 448. 

Length, an idea of determinate, not 
in mind, 149, 150; preserved only 
by real measures, 150 ; pyramid to 
serve as standard, 150; pendulum 
measures, 150. 

Lentulus, 308. 

Lerins, Vincent de, 617. 

Lessius, 153. 

Lethargy, 166. 

Liars who contradict themselves uni- 
versally obnoxious, 23, 77. 

Licetus, 351. 

Life, a good one preferable to a bad, 
apart from eternal felicity, 217 ; 
Epicurean doctrine, even apart from 
felicity, not most reasonable, 217 ; 
indefinite ideas of, 388; notion of, 
is accompanied by perception in 
the soul, 388 ; of man, that it should 
be a dream, not impossible meta- 
physically, but rationally, 422 ; even 
if a dream, does not deceive, since 
its phenomena are in reliable series, 
422. 

Light, why referred to fire, 133 ; rel- 
ative to suitable organs, 133; like 
sugar, 140 ; Aristotle's definition of, 
321. 

Light, internal, what ? 22, 599 ; opposed 
by perceptions of sense, 98 ; is source 
of science, law, and morals, 98; its 
struggle with perception of sense 
described in Scripture and ancient 
and modern philosophers, 98; dulled 
by sense and custom, 98; — natural, 
74. 

Lights, first, 499. 

Lignum nephriticum, 432. 

Lingua Franca, 293; Zerga, 293. 

Lion, known by claw, 357 ; its deriva- 
tion, 300, 301. 

Lipenius, 626. 

Livy, his accounts of battles imagi- 
nary, 543. 

Locke, John, his Essay concerning 
human understanding, 4; denies in- 
nate ideas, 4 ; declines reply to Leib- 



800 



LEIBNITZ'S CRITIQUE OF LOCKE 



nitz's criticism on his Essay, 6 ; on 
axioms, 12 ; on logic, 12 ; on the 
Infinite, 12 ; his change of view on 
Newton's theory of gravitation, 12 ; 
both assayer and transmuter, 19 ; in 
his view of reflection relaxes his doc- 
trine about innate ideas, 45; denies 
anything virtual in us, 46 ; believes 
that mind does not always think, 
47 ; his antagonism to innate princi- 
ples explained, 71. 

Logic, its fruitf ulness, 12; valuable, 
18 ; full of truths which can only be 
proved by innate principles, 44; a 
natural, 88; has it helped to main- 
tain the obscurity of words, 378; 
ignorance of, accounts for inaccurate 
use of terms, 379 ; as much a demon- 
strative science as mathematics, 414 ; 
of geometers but a part of general, 
414 ; of probabilities suggested, 541 ; 
chains of reasoning in, whence their 
complexity, 561; laws of, principles 
of good sense reduced to writing, 
562 ; a severe, not necessarily scho- 
lastic, needed in practical delibera- 
tions, 563 ; because men reason 
without artificial, does not prove its 
inutility, 563; its scholastic forms 
inconvenient, 564; have its rules 
entire sway in probable questions? 
565, 566; of the probable, Cardan 
on, 566; a sublime, suggested, to 
which common is but as alphabet, 
566 ; its possible improvement, 566 ; 
Hooker upon its improvement, 566 ; 
as a universal mathematics, 569 ; in 
what particulars reason needs it, 
570; not needed in intuitive knowl- 
edge, 574 ; what it comprises, 621 ; its 
contents according to the ancients, 
622; includes artes dicendi, 622; its 
boundaries indefinite, 622; discur- 
sive, 623 ; medicinal, 624. 

Logical form reveals force of argu- 
ment, 562. 

Lombards, brothers of the, 449. 

Lot, man's, a ground of praise rather 
than complaint, 439. 

Loubere, M. de la, 60. 

Louis le Debonnaire, the oath of, 294. 

Love, what? 167, 168; extension of 



term, 168 ; of complacency, 168 ; of 
benevolence, 168; disinterested, 168. 

Lucan, a sally of his criticised, 144. 

Lucian, his " True History," 399. 

Ludolphe, 75. 

Lully, Raymond, 590. 

Lunafixa, 324. 

Lune, its quadrature by Hippocrates, 
527 ; axiom employed in its quadra- 
ture, 527. 

Lutheran view of Eucharist, 611, 612. 

Lutheranism, name disapproved, 544. 

" Lux in Tenebris," 604. 

Luz of the Rabbis, 242. 

Lynx, its derivation, 301. 

Lysimachia, 267. 

Machine, its archetypes, 280. 

Madmen, their defects, 146 ; from rev- 
erie, 166. 

Magnetology, a science, 525. 

Magnitude, 258. 

Magots, 342, 343. 

Mais, its equivalents in German, 366; 
its derivation, 367 ; its elliptic use, 
368. 

Malotru, Abbot, 351 

Man, should we call an irrational creat- 
ure in human form a ? 244 ; should we 
call a parrot discoursing philosophi- 
cally a ? 244 ; requires not merely rea- 
soning soul, but something of figure 
and constitution of body, 245; can- 
not be a machine, 246 ; a social being, 
285 ; his speech the instrument and 
bond of society, 285 ; how the name 
is arrived at, 310 ; what creatures 
may be so called, 342 ; definition of, 
at once real and nominal, 342; no 
rational animal has yet been found 
with a body differing much from 
that of, 351; definitions of, Aris- 
totle's, 384; definitions of, Plato's, 
384; a working definition of, 391,392; 
the most stupid, more rational than 
the most spiritual beast, 552, 553 ; ad- 
vantage of his position on the globe, 
575. 

Man-ness {V hommeite) , 369. 

" Mansions " applied to planets, 548. 

Manual arts, their principles should be 
taught by scholars, 628. 



INDEX A 



Marble, a veined block of, tbe illus- 
tration of, 4G, 76, 82, 84; block of, 
with or without veins, 46. 

Marcus Aurelius, 495. 

Marian islanders, 104. 

Marinus, 465. 

Marionettes regarded as alive, 388. 

Mariotte, M., an experiment of, 121; 
on the color blue, 337. 

Martin Corneille, his attempts to rec- 
oncile philosophy and religion, 581. 

Masham, Lady, 65. 

Mass, an image of substance, 219. 

Materia prima, has impenetrability, 
383 ; has inertia, 383. 

Mathematics, paralogisms of, faults of 
form, 18; some propositions demon- 
strated outside of, 272, 414 ; not the 
only science capable of demonstra- 
tion, 414 ; why it has become so per- 
fectly demonstrative, 414. 

Mathematicians, accused of passion 
for glory, 93. 

Matter, how regarded by Locke, 11, 
16; how regarded by Leibnitz, 11, 16 ; 
"medley of effects of surrounding 
infinite," 51 ; is not rigid, 54; can it 
think? 56, 59, 61, 62, 427; contro- 
versy with Bishop of Worcester 
regarding, 56 ; distinct from exten- 
sion, 155; secondary, 231 ; primary, 
possesses a perfect fluidity, 231 ; its 
indivisibility, a perplexed notion, 
234; distinct from body, 383; are 
discussions concerning, as materia 
prima futile ? 383 ; can it think, 
427; primary, purely passive, and 
therefore incomplete, 428; primary, 
cannot produce perception, sensa- 
tion, reason, 428 ; secondary, a 
complete being, 428 ; secondary, a 
real mass, 428 ; secondary, supposes 
real unities, 428; secondary, its 
unities percipient, 428 ; secondary, 
constitutes au intelligible world of 
substances, 428; secondary, when 
God gives it organs for rational ex- 
pression He gives it immaterial 
thinking substances, 428; second- 
ary, substances of, have within 
them correspondence or harmony, 
428 ; secondary, primitive powers of, 
3f 



are substances themselves, 428 ; sec- 
ondary, derivative powers of, are 
modes of being, 428 ; new hypothe- 
sis of, attributes to soul and body 
only the modifications we experi- 
ence in ourselves and them, 430; 
new hypothesis of, gives to our 
ideas of matter greater regularity 
and connection, 430; presents diffi- 
culty only to those who must im- 
agine what is only intelligible, 430 ; 
changes in, dependent on reasons 
incapable of arising from extension 
and natures purely passive, 430; 
changes in, cannot arise even from 
particular and inferior active na- 
tures without the pure and univer- 
sal act of the superior substance, 
430 ; not unintelligible, but in parts 
not clear because of our confused 
perceptions, which contain the infi- 
nite, and are the detailed expression 
of what occurs in bodies, 431 ; can- 
not produce pleasure or pain, 431 ; if 
susceptible of thought, may create, 
501 ; if first eternal thinking being, 
means an infinite number of think- 
ing beings, 506 ; cannot give rise to 
perceptions, 507 ; not a monad or 
unity, 507; a mass of an infinite 
number of beings, 507; each being 
of, is material or immaterial, 507; 
has a General and Superior Cause, 
507 ; under Pre-established Harmony, 
507 ; all is, 518. 

Maurier, his slanders on Grotius, 542. 

Maurolycus, 442. 

Maxims or Axioms, on what their self- 
evidence rests, 462 ; are they evident 
ex terminis, 462; demonstrated by 
geometers, 462; when to be assumed, 
464 ; their use, 473, 474 ; their intro- 
duction into public disputations, 
477, 478, 479; formed through an 
instinct, 481 ; bad use of, 482 ; help- 
ful to knowledge, 484, not to be 
blamed for improper use of terms, 
484 ; of special use in long processes 
of reasoning, 485 ; how formed, 485 ; 
use in mathematics, 485; use in 
jurisprudence, 486; what included 
under, 486 ; fundamental, 487 ; some- 



an- 



LEIBNITZ'S CRITIQUE OF LOCKE 



times employed out of season, 489; 
identical, not nugatory, 490; their 
use, 491; semi-identical, their use, 
492; by many regarded as basis of 
knowledge, 517; relieve memory, 
517; not arrived at by induction, 
517 ; are present implicitly in exam- 
ples, 518 ; exist in minds of all men, 
518 ; their certainty dependent on 
comparison of ideas, 519 ; must not 
be assumed gratis, 519 ; borrowed by 
subaltern sciences from superior in 
which they have been proved, 519; 
accepted provisionally, 520. 

Medicine, the antiquities of, important, 
371, 372; improbability of a better 
science of, 442 ; bad use of terms in, 
443 ; well-detailed observations desir- 
able in, 489 ; as an indicial term, 627. 

Meditation, 166. 

" Meditationes de Cognitione, Veri- 
tate, et Ideis," 3, 14. 

Medius terminus often sufficient, 481. 

Megiddo, battle of, 547. 

Meier, Gerard, philologist, 304. 

Melauchthon, his views of Eucharist, 
612. 

" Memoir es de Trevoux," 502. 

Memory, and reminiscence, 77 ; effects 
of former impressions without, 106 ; 
does not make same man, 114; after 
a time may deceive, 248 ; immediate 
and internal, cannot deceive, 248; 
mediate and external, may, 248; 
its fallibility, 403; an illustration 
of, from keeping accounts of Hartz 
mines, 403; how Leibnitz applied 
laws of, in keeping accounts, 403; 
its functions, 513; its limitations, 
514, 

Men, deprived of speech use other 
general signs, 145 ; with tails, 341 ; 
distribution of beard among, 341 ; 
prefer to deceive and be deceived, 
389. [545. 

Menage, his abbot of Saint Martin, 350, 

Mercures Galans, 438. 

Mere, Chevalier de, his " Agremens," 
539. [495. 

Metaphysic, a real, being established, 

Metaphysics, abstracts of, teach only 
words, 493; the most general science 



according to Aristotle, 495 ; ethics, 
how related to, 495. 

Metempsychosis, 53, 68. 

Microscope, 227, 228; its use recom- 
mended, 553. 

MucpSv, rb, not to be neglected, 51. 

Milky Way, Democritus' correct sur- 
mise regarding, 277. 

Mill, why unconscious of its continu- 
ous noise ? 47. 

Mind, things may be in, of which one 
is not always conscious, 20; may take 
necessary ideas from itself, 78 ; has 
more than mere passive capacity for 
receiving impressions, 80; is not as 
wax or tablet, 80; and judgment, 
distinguished, 144; are its ideas of 
itself no clearer than its ideas of 
substance? 226; the Supreme and 
Universal, 516. 

Miracles, not to be recurred to in ordi- 
nary way of nature, 55 ; accepted in 
despite of analogy, 553; refused by 
Christ, when ? 606. 

Miraculous, its use in philosophy, 61. 

Mirror, knowledge of its construction 
as affecting rays of light, an illustra- 
tion of interior constitution of sub- 
stance and its relation to qualities, 
458. 

Misery, what? 200. 

Mixed, conclusion, 84 ; modes, acquired 
by observation, 222 ; modes, acquired 
by invention, 222; modes, acquired 
by explaining terms, 222; modes, 
acquired in dreaming and reverie, 
222,223 ; modes, are they real? 329; 
modes, do we always change species 
of, with change of a constituent idea, 
385. 

Mixta imperfecte, 361. 

Mode, a geometrical, may be referred 
to specific essences, 386. 

Modes, the, according to Locke, 5; 
their kinds, 5 ; what ? 148 ; majority 
of, not simple, 164; mixed, what? 
221; how distinguished from ideas 
of substance, 221; dependent on 
mind, 276; must be possible and 
compatible, 276; may be real acci- 
dents, 277 ; ingredients of, must be 
compossible, 277 ; impossible, can be 



INDEX A 



803 



invented, 280; if an idea in one of 
them changed, it becomes another 
thing, 385. 

Modification and attribute distin- 
guished, 58. 

Modifications which may belong nat- 
urally to a thing, 60. 

Mola, 344. 

Molyneux, his problem as to a man's 
power of discriminating between a 
cube and globe presented to him for 
the first time after obtaining sight, 
138, 139, 141; his Dioptric, 484. 

Monad, defined, 147. 

Monads, doctrine of, 101 ; substantial 
unities, 231 ; not mass, 507 ; how the 
soul acts in, 507 ; Bayle s objection 
to theory of, 507 ; originate from 
God and depend dh Him, 511 ; the 
"how in detail" incomprehensible, 
511; their conservation a continual 
creation, 511; doctrine of, evident 
everywhere, 553. 

"Mouatliche, Auszug," 5; Leibnitz's 
sketch of Locke's essay in, 7, 26-38. 

Money, should not be debased, 578. 

Monkeys, said to possess organs of 
speech, 287. 

Monster, is it a man ? 314 ; can it be a 
species midway between beast and 
man, 447, 448 ; his future state dis- 
cussed, 447, 448; possession of rea- 
son settles its manhood, 448; its 
birth and shape presumptions of 
its rationality, 448 ; we save it from 
destruction during uncertainty, 449 ; 
not made for nothing, 449. 

Monsters, 344, 345, 346, 350, 351, 352; 
their classification discussed, 339. 

Montausier, 605. 

Mood, one added to fourth figure, 561. 

Moods, in each figure six, 560; four 
common, what ? 560 ; two added to 
first figure, 560 ; two added to sec- 
ond figure, 561. 

Moon, emperor of, his saying, 574. 

Moral entities, their reality, 329 ; re- 
garded as " things " by jurisconsults, 
329. 

Moral, good, 260; evil, 260; sphere, 
436. 

Morality, truths of, demonstrable, 86 ; 



laws of, their violation does not 
disprove them to be innate, 93; ob- 
scured by excesses, 93 ; their neces- 
sity not demonstrated as it ought to 
be, 93 ; its principal point God's so- 
cial connection with us, 247 ; partly 
founded in reason, partly in experi- 
ence and disposition, 392 ; " the New 
Hypothesis" lays deep the founda- 
tions of, 433; consideration of goods 
of life conduces to, 433; its questions 
can be decided as incontestably as 
those of mathematics, 433 ; diagrams 
proposed in, 435 ; definitions invalu- 
able in, 435 ; algebra may help, 435 ; 
Weigel's diagrams to illustrate, 435 ; 
are its problems simpler than those 
of geometry, 436? ideas of, are they 
of human invention, 446 ; the proper 
science of all men, 525. 

More, Henry, 67; his "aerial vehi- 
cles," 3S0; his " Hylarchic princi- 
ple," 382. 

Moses, 37. 

Motion, in Aristotle, 174; by physical 
impulse and by thought, is it con- 
ceivable in either instance ? 232 ; its 
transference as an accident not con- 
ceivable, 232 ; amount of, lost in 
impact of bodies, 232. 

Motions, never lost, 24 ; become indis- 
tinguishable, 25 ; according to Aris- 
totle, 174, 320; real phenomena, 
219 ; image of action, 219 ; motivity, 
220; laws of, derived from a cause 
superior to matter, 233; produced 
by thought, no idea or experience 
of, 233. 

Motive, the present and the sensory 
furnish a stronger, than the future 
and reasonable, 92. 

Mouton, 150. 

Murder, its degrees employed to illus- 
trate how mixed modes change in 
species with change of a constituent 
idea, 385. 

Musseus, Jean, 590; "Use of Reason 
in Theology," 587, 588. 

Mussels, perception in, 142. 

Name, why not given to murder of an 
old man? 222. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Names, family, 258, 259 ; how bestowed 
on tribes, 251) ; improper use of, gives 
rise to confusion (obscurity) of 
ideas, 268, 271 ; how they should be 
einjtloyed, 271 ; a particular one for 
each thing impossible, 307 ; such mul- 
tiplicity would baffle the end of lan- 
guage, 307 ; such multiplicity would 
not extend our knowledge, 307 ; 
proper, their use, 307 ; have usually 
been appellations at first, 307; of 
species, how given, 308 ; first used 
by young children personal, 309; 
their influence, 328; of substances 
say more than definition, 393, 391. 

Narquois, 293. 

Nations, common origin of, 297. 

Natural light, 36, 38, 86, 88, 89, 92, 96, 
597. 

Naturally, or, "in the order of nat- 
ure," defined, 60, 61. 

Nature, questioning, 18 ; makes no 
leaps, 50; of things and of mind 
agree, 74; labors to put herself 
more at her ease, 194 ; a good econo- 
mist, 356 ; grand in effects, sparing 
in causes, 356; proceeds by shortest 
paths, 484; its order, not of meta- 
physical necessity, 582 ; grounded in 
good pleasure of God, 582 ; may de- 
viate therefore for superior reasons 
of grace, 582. 

Naude', 580. 

Naudeana, 580. 

Nebuchadnezzar, 545. [486. 

Ne quis alterius damnofiat lucupletior, 

Necessary, idea of, founded on pre- 
sumption of God's reasonable im- 
mutability, 180. 

Necessary trutb, when possible to 
prove, 3; what? 4, 326. 

Necessitate meclii, 620 ; Prsecepti, 620. 

Necessity, never proved by experience, 
22 ; when thought wanting, 182 ; when 
compulsion, 182 ; when restraint, 182 ; 
of geometrical and metaphysical con- 
sequences, 183; does not enter into 
physical and moral consequences, 
183; opposed to contingency, 183; 
not determination, 183. 

Need, art of thinking in time of, 214. 

Nicole, M., 617. 



Nihil est in intellectu quod nonfuerit 

in sensu excipe nisi ipse intelleclus, 

111. 
Msi, elliptic use of, 368. 
Nisus, in Vergil, 598. 
Nodus in scirpo, 460. 
Nomenclator, 330 ; an illustrated, 

printed at Nuremberg, 395. 
Nominalists, 178, 623 ; seemed to make 

nature seem stingy, 356. 
Nominati, in Roinau law, 360 ; age of 

puberty, an example of, 360. 
Non-appearance, not equivalent to 

non-being, 98. 
Non-consistence of bodies, 124. 
Nothing cannot produce real being, 

500, 501. 
" Nothing in us but of what we have 

been formerly conscious," 46. 
Notion, what? 221, 222, 493; the true 

mark of a clear and distinct, 227; 

the word discussed, 329. 
Notoriety, as evidence, 538. 
"Nouveaux Essais," their origin, 5, 6. 
" Nouvelles de la Republique des 

Lettres," 50. 
Novelle of Boiardo, 398. 
NugatOii.se, 490. 
Number, 220; knowledge of, not in 

animals, 145; ideas precise in, 160; 

has no minimum in extent, 160 ; col- 
lective idea in, 160; memory in, 160; 

does not depend on imagination, 273 ; 

short methods in, desirable, 570; 

prime, how to recognize easily, 571. 
" Number, The great," argument from, 

617. 

Oates, 65. 

Oath cannot fix opinion, though it may 
teaching, 619. 

Obediential power, 428. 

Obreption, 276. 

Occam, 588. 

Occult qualities, 63, 204, 431. 

Ocker, 302, 308. 

(Ecumenical councils preserved from 
error as to doctrine, 618. 

Old man of the mountain, 196. 

Oldenburgh, 526 ; Count of, 259. 

" One and one make two," a defini- 
tion, not an axiom, 23. 



INDEX A 



805 



" One and two are three," 471. 

Opal, 432. 

Opinion, the perception of a truth, 92 ; 
natural, the perception of an innate 
truth, 92; its value in support of 
truth, 530 ; freedom of, what ? 537 ; 
how acquired, 556. 

Opinions, voluntary indirectly, 528; 
theoretic, their practical influence, 
535 ; how they spread, 535. 

Opposition, hetween the individual and 
the public an evil, 620; between 
sects, an evil, 620 ; often an accident 
of party rather than result of rea- 
soned conviction, 620. 

" Opposite angles made by intersec- 
tion of two straight lines an equal " : 
is this truth innate ? 105. 

Optics, may be learned by the blind, 
140 ; founded on maxim that nature 
proceeds by the shortest paths, 484. 

Oracles, internal, derived from early 
education, 611. 

Orel galea, 479. 

Order, tempore vel natara, 82 ; of analy- 
sis, different from that of occasion, 
220 ; the natural distinguished from 
the historical, 470. 

Orders of Rome, have narrower rules 
than their Church, 619. 

Origin of ideas, not preliminary in 
philosophy, 15. 

Ostensives, the, 491. 

Ostracism, 222. 

Otfried, gospel of, 294. 

Ourang-outang, man may become as 
stupid as, yet preserve rational soul, 
244; illustrative of human form 
without human soul, 244. 

Outlines, impression on empty tablets 
of mind, a thing of self-perception, 
20. 

Oyster, perception in, 142; tossed by 
monkey, an illustration, 491. 

Pain, and pin, relation between, 133 ; 
why referred to body? 133; rudi- 
ments of, their place in our welfare, 
170, 171 ; includes apperception, 194; 
partly unconscious, 195 ; what? 200 ; 
a feeling of imperfection, 201. 

Fainting, deceives by metonymy and 



metaphor, 137 ; in fresco, some good 
things like, 173; a, which was only 
intelligible when looked at through 
a cylindrical mirror, 269. 

Pajon, 595. 

Pallium, 394. 

Pandects, 296, 415 ; similarity of style 
among authors far separated in time, 
416. 

Pappus, 573 ; on analysis, 521, 565. 

Parabola, how one may add to his idea 
of, without changing its concealed 
constitution, 386. 

Parallel lines, their definitions, 318. 

Paralogisms often dependent on as- 
sumptions, 481. 

Paralytic, could learn geometry, 139. 

Parrhesia, irappyjaia, 223. 

Parricide as a possible crime, 325. 

Parrot who talked philosophy, would 
it be a parrot ? 244. 

Parrots, possess words without organs 
of speech, 287. 

Partes extra partes, 163. 

Particles, what ? 364 ; their use, 364 ; 
not absolutely necessary, 364 ; their 
explanation, 366, 367; may connect 
parts of an idea, 364; should be in- 
vestigated, 36S; catalogues of, 365; 
concealed in inflections of nouns and 
verbs, 365 ; best explained by para- 
phrase, 367 ; by ellipsis equal to com- 
plete sentiment, 368. 

Particular propositions appear as uni- 
versal affirmations, 568. 

Pascal, on calculations of chances, 
539. 

Passah, Hebrew, 361. 

Passion, how controlled, 207; or pas- 
sive power discussed, 218; towards 
imperfection, 219; when it is con- 
fused, a step towards pain, 219. 

Passions, whence? 167; what? 172; af- 
fect body, 173 ; can be mastered, 207 ; 
their illogical influence, 614, 615. 

" Pater, space of," 578. 

"Patience, forced," of soul, 496. 

Paul, St., 43, 153. 

Paulus, jurisconsult, his rule, 486. 

Pearls of Slusius, geometric figures 
about which much was known before 
they were found to be cubic parabo- 



sou 



LEIBNITZ'S CRITIQUE OF LOCKE 



loids, 387 ; or the lines of the cubic 
parabola, 405. 

Peas, throwing, against pins, 208. 

Pelisson, 591, 592. 

Pendulum, employed to measure 
length, 150, 150; called in German, 
" unruhe," 171. 

Penn, 002. 

Pensees volantes, 182. 

Perceptions, exist too feeble to be re- 
membered: illustration of , 24 ; if we 
did not always have, could not be 
waked from sleep, 24 ; illustration of 
man waked by several voices, not by 
one, 24; never lost, 25; become in- 
distinguishable by composition, 28; 
without apperception infinite, 47 ; 
reasons why we may not be conscious 
of, 47, 48; insensible, their efficacy, 
form images of qualities, 48; con- 
nect each being with rest of uni- 
verse, 48 ; make present big with 
future, and laden with past, 48; 
insensible, explain Pre-established 
Harmony, 49 ; insensible, render 
death a sleep, 49; iuseusible, con- 
stitute sameness of individual, 49; 
insensible, their determining influ- 
ence, 49 ; and objects, their relations 
not arbitrary, 50; insensible, give 
rise to noticeable perceptions, 50; 
insensible, of use in pneumatology, 
50; insensible, explain why souls are 
never perfectly alike, 50, 52 ; not 
perceived or remembered, known 
only by consequences, 112 ; have 
them while asleep, 112; minute, 
mental, though not perceptible, 
have effects, 110 ; unpremeditated 
actions, result of minute, 110 ; thence 
customs, 110 ; thence passions, 116 ; 
these in morals, what corpuscles are 
in physics, 116 ; prevent indifference 
in moral actions, 116; incline with- 
out necessitating, 110 ; of which not 
conscious, 121, 135; defined, 135; 
animals have, 135 ; have we, uncon- 
sciously? 135 ; mind passive in, 135 ; 
Locke denies unconscious, 136 ; in 
plants, 141, 142 ; of images, 142, 143 ; 
feeble, in oyster and mussel, 142 ; 
never without minute, 166; none 



indifferent to us, 167; confused, 
advantages of, 170 ; perceptible 
only in mass, 199; pertain to all 
the entelechies, 218; in enthusiast, 
597. 

Perfection, man's highest, in search 
for true happiness, 206. 

Perfections, certain, bring greater im- 
perfections, 208, 209. 

Peripatetics, 65 ; obscure, 378 ; on rare- 
faction and condensation, 124 ; their 
ten predicaments, 380. 

Perpetual mechanical movement, il- 
lustration of au "apparent idea," 
505. 

Persians, doubts about the history of 
the, 545. 

Persius quoted, 272. 

Person, its content according to Locke, 
245. 

Persons, can there be two with same 
immaterial substance ? 248. 

Peruvians, their cruelty, 89. 

Petronius, " adolescentes in scholls 
stultissimos fieri," 482. 

Phsedo, Plato's, 170. 

Phantasms, 459; sensitive, 459; good 
term for "secondary qualities" or 
"sensitive ideas," 459; confused, 
cannot abide if distinguished into 
ingredients, 459. 

Phantoms of sense opposed to pure 
ideas, 78. 

Pharsalia I, 128, 144. 

Philalethes, why the name was as- 
sumed, 69. 

Philanthropy defined, 91. 

Philology, 372. 

" Philosophia Mosaica," 63. 

Philosophy, practical, 021 ; as an indi- 
cial term , 027 ; introductory to other 
divisions, 028. 

4>opd, its signification, 321. 

Photis (Fotis) and the golden ass, 243. 

Physical laws, as to God, not neces- 
sary, 183. 

Physicist, 525. 

Physics, as a whole, will never be a 
perfect science, 525 ; some parts of, 
scientifically detailed, 525; cannot 
give a reason for all experiments in, 
525 ; its content, 621. 



807 



Piety, practical, 526 ; natural, does it 
save? 590,591. 

Pin, and pain, 133 ; affrights, 283. 

Pineapple, cannot experience its taste 
by account, 321; its cultivation, 322. 

Pisani, Ottavio, his "Lycurgus," 283. 

Piso, 308. 

Place, what? 152; particular, 152; 
universal, 152 ; if nothing fixed, 
could yet be determined, 152 ; an 
order of coexistences, 229. 

Planetary communication, complica- 
tions connected with, 343. 

Plants, fecundation in, 338. 

Plato, 392; supposed to believe that 
soul has originally principles or 
ideas, 42, 43 ; his idea of matter, 66 ; 
his " Meno," 78; on conscience, 91; 
his "Pluedo," 170. 

Platonist, his soul of world, 380, 382; 
hjp reminiscence refuted, 105. 

Pleasure, how founded ? on semi- 
pleasures, 170; on semi-pains, 170; 
a step to happiness, 200 ; its low- 
est degree, 200; its most estimable 
kind, 200; what? 200, 201; feeling 
and appetite carry to, 201 ; can grow 
infinitely, 201 ; cannot have a nomi- 
nal definition, 201 ; allows a causal 
definition, 201 ; and happiness dis- 
tinguished, 207 ; a feeling of perfec- 
tion, 200, 201, 208; or displeasure 
accompanying an action can be 
changed, 216 ; good, of God, defined, 
431 ; cum ratione insanire, an ele- 
ment in, 459. 

Pleasure and pain, 167-173 ; not capable 
of nominal definition, 167 ; affinity 
of, 170 ; pertain only to mind, 200 ; 
originate in mind and body, 200, 
202 ; not in matter but in soul, 430. 

Pleasures, luminous, how they improve 
us, 207 ; confused', the danger of, 207 ; 
two cannot be enjoyed at once, 210 ; 
can they be enjoyed with pain ? 211 ; 
do men diminish future? 212. 

Plenum, unnecessary hypothesis, 54; 
uses of, 54. 

Pliny, on Democritus, 66. 

Plus vident oculi quam oculus, 617. 

Pluto, his helmet, 479. 

Pneumatics, doctrine of spirit, 362. 



Pneumatology, 52. 

Point, defined, 156. 

Polemo, " the world is God," 518. 

Police, a better, desired, 438, 526. 

Pollen, 338, 347. 

Polygon, to illustrate relations, 236. 

Poniatovia, prophet, 604. 

Portugal, Sea of, 134. 

Possible, 'distinctly intelligible,' 277. 

Power, idea of, how formed, 130, 174 ; 
possibility of change, 174; active, 
may be called force, 174 ; active, the 
proper attribute of spirit, 174, 233; 
passive, as mobility and resistance, 
174, 175; passive, that of bodies, 
174, 177, 233 ; a simple idea through 
ignorance, 175 ; relation of, 175 ; 
active, idea of, furnished by reflec- 
tion, 175, 177 ; an obscure idea of, 
given by an impinging body, 176 ; its 
noblest sense, 176 ; active, in entele- 
chies alone, 177; liberty the most 
important form of, 218 ; what ? 224 ; 
includes tendency, 224 ; an entelechy, 
224. 

Powers, pure, are fictions, 110; real, 
not possibilities, 112 ; have tendency, 
112. 

Praetor's album, 44, 86. 

Predicaments, 361 ; use of, important, 
311, 380; the ten, of the Peripatetics, 
380; may be reduced, 380. 

Predicate is in subject, 568, 569. 

Pre-established Harmony, 49, 230, 
233, 252, 333, 421 ; requires sensible 
outlines, 78 ; explains motion of 
bodies, 229 ; its influence on theology 
and pneumatology, 363. 

Pre-judgments, by which men would 
except themselves from discussion, 
531 ; legitimate in the Romish con- 
troversy, 531. 

Prejudice, 98, 99. [364. 

Prepositions, their use and origin, 290, 

Prescriptions of Tertullian, 531. 

Presentiments, we have, 15. 

Presumptions, what? 260; of the juris- 
consults, 538, 616. 

Primary matter, 231. 

Primitive language, see Language. 

Primitive truths cannot be proved by 
anything more certain, 410. 



LEIBNITZ'S CRITIQUE OF LOCKE 



"Prince, a great," as benefactor of 
the race, expected by Leibnitz, 438, 
629. 

Prineipmm individuationis, 239. 

Principle of principles : union of 
definitions by means of identical 
axioms, 521. 

Principles, first, according to Leibnitz, 
13 ; on which men agree, 71 ; not im- 
pressions which minds receive with 
their existence, 71; universal con- 
sent does not prove them innate, 71 ; 
not universal, 71; the two great 
speculative, 77; first, how arrived 
at, 99; should be open to judicious 
investigation, 108, 473. 

Probabilities, mathematical calcula- 
tion of, 539 ; illustrated, 540, 541 ; 
a new logic of, 541 ; methods of es- 
caping unpleasant, 014, 615. 

Probability, the part of logic which 
estimates, still wanting, 213; Aris- 
totle's mistake concerning, 214; its 
consideration important yet neg- 
lected, 417; degrees of resem- 
blance {ex clatis) can be determined, 
417; teaching of Jesuit moralists 
concerning, 41S; must be drawn 
from tbe nature of things, 419; 
opinions of persons collateral only 
to its determination, 419; opinion 
of Copernicus, though he was alone, 
had most, 419; art of estimating, 
more useful than most demonstra- 
tive sciences, 419; grounds of, 529, 
530, 532; its highest degree, 538; 
nature of, 529, 585; false measures 
of, in what they consist, 611 ; one can- 
not lean to side of less, 615. 

Probable reasoning of jurisconsults, 
577. 

Problems, what? 411. 

Proclus, 108, 463, 491; demonstrates 
axioms, 14; his philosophical style, 
416. 

Procopius, when credible, 542. 

" Proferendis, Be, scientix demon- 
strandi pomoeriis," 437. 

Progress, in all things, 142 ; to be ex- 
pected, 440, 629. 

Progymnasmata, 399. 

Projection, of a circle on a plane, illus- 



trative of relation between idea and 
its cause, 133. 

Prolepsis, of Stoics, 43. 

Proof, advantage of continued appli- 
cation of, 402, 403; complete, 538; 
more than complete, 538 ; more than 
half complete, 538; less than half 
complete, 538 ; slender, should it in 
criminal charges be in any case ac- 
cepted against a man ? 577 ; slender, 
accepted against a man not to con- 
demn him, but to prevent him doing 
harm, 577. 

Proofs, 411. 

Propositions, which secure acquies- 
cence as soon as heard, are they 
found in physics as well as mathe- 
matics ? 83 ; identical, do not admit 
proof, 83 ; universal, of the truth or 
certitude of, 452; being certain of, 
454 ; can they be obtained by expe- 
rience of "consequences in a con- 
stant manner " ? 461 ; express as 
late an effort of mind as formulat- 
ing axioms, 470 ; general, concerning 
substance, are often trifling, 493; 
some grand and beautiful, 494; uni- 
versal, do not relate to existeuce, 
498; universal, may be accidental, 
498 ; a division of, into general and 
particular, virtually a division into 
those of fact and those of reason, 
514 ; capable of a certain generality, 
514; of reason, 515 ; mixed, 515; how 
far general and certain, 515; cate- 
gorical and hypothetical, how re- 
lated, 515, 516; of two kinds: of 
fact, 537 ; of speculation, 537. 

Propensities, insensible perceptions of 
perfections and imperfections, 201. 

Proper names, originally appellatives, 
307. 

Property, term discussed, 433, 434. 

Prophecies, instances of pretended, 
604; their bad effects, 605; alleged, 
said to have had a good effect, 606. 

Proportion, the relation of, 258. 

Propriety, regard for, among men, 91. 

Prosc?-iptio, 222. 

Prosthaphseresis, in probability, 540; 
how employed by peasantry, 540. 

Protestants, non-opinionative, may be 



INDEX A 



saved, according to some Romish 

doctors, 591. 
Proverbs, 481. 
Psittacism, 191, 196. 
Public, opinion, its force, 262; spirit 

depends on morality and religion, 

536. 
" Public spirits," 536. 
Puccius, Franciscus, 593. 
Puffendorf, 435. 
Punishment, 260. 
Pyramid, conservation of measure by, 

150. 
Pyrenees, 308. 
Pythagoras, 100, 474. 

" Quaken," as a stem, 298. 

Quse uno spiritu continentur, 241. 

Quakers, 599. 

Qualities of things, defined, 131 ; pri- 
mary, what ? 131 ; secondary, what ? 
132 ; power, when regarded amoug 
the primary, 132; power, when re- 
garded among the secondary, 132; 
secondary, their relations to corre- 
sponding ideas, 133 ; even primary, 
do not appear uniformly, 134 ; clas- 
sified upon basis of most common 
conditions, 134; real, what? 134; 
what? 148; sensible, confused, 432 ; 
sensible connections known only 
through experience, 432 ; analysis 
employed in, 432 ; secondary (sensi- 
tive ideas), their relation to interior 
constitution of bodies, a confused re- 
sultant of the actions of bodies upon 
us, 458. 

Quarto modo, properties in, how appli- 
cable to infima species, 455. 

"Quek," 299. 

Questions, are themes between ideas 
and propositions, 398. 

Quia inter omnes homines, etc., 91. 

Quietists, " bad," 53; " idle," 526. 

Quinquina, 525. 

Quodlibets, 419. 

"E," employed to signify a violent 

movement and noise, 299. 
Rabbinage, 372. 
Ragosky impelled to attack Poland, 

604. 



Ramists, 398. 

Ramus, Peter, on the reduction of logi- 
cal figures, 408, 409. 

Rank, of man in scale of being, 439; 
carries with it requirements, 609, 
610. 

Rarefaction, of matter, 124; none, 
127. 

Raspe, publisher of " Nouveaux Es- 
sais," 10. 

"Rauschen," defined, 299. 

Realists seem to make nature prodigal, 
178, 356. 

Reality, what? 22, 148; of relations 
depends not merely on the minds of 
men but on that of God, 276, 277 ; of 
the nominal definition, 316; of our 
knowledge, 444. 

Reason, natural revelation, 32 ; essen- 
tial to all revelation, 32; its place 
in investigating an alleged revela- 
tion, 36 ; of men, 69 ; animals have, 
145 ; prefers to consecrate term 
to man, 146; to declaim against, 
foolish, 206; "a concatenation of 
truths," 206; consists in knowing 
the truth and following the good, 
206 ; depends on characters, 220 ; 
Leibnitz's definition of, 555 ; Locke's 
definition of, 555; a special defini- 
tion of, 555 ; its uses as defined, 555 ; 
a priori, 556 ; in truths corresponds 
to cause in things, 556; confined 
to man, 556; apparent in auimals, 
what? 556; its two parts, 556; its 
four degrees, 556 ; one of these not 
apparent, 556; contrary to, when? 
578 ; above, when ? 578, 579 ; things 
beyond our present faculties not 
above, 578, 579 ; not opposed to faith, 
580; defined, 583; used by all as 
long as it seems to aid them, 583; 
in theology agitated between Socin- 
ians and Catholics, 585 ; and custom, 
difficult to satisfy both, 609. 

Reasoning, an oddness in some people 
due to a non-natural connection of 
ideas, 282; what? 411; all, springs 
from things already known and 
agreed to, 413; is ex prsecognitis 
et prseconcessis, 413, 470 ; claims of, 
an infinite number of, 561. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Recalling absent ideas, an active 
power, 219. 

Receptivity, 174. 

Recollection, its two meanings, 165. 

Reduction, of figures in logic best ef- 
fected by principle of contradiction, 
407. 

Reflection, according to Locke, 4; " a 
regard for what is in us, and born 
in us," 11, 45; more than Locke 
makes it, reaches mind, 23, 24, 45, 
75, 82; where Locke approaches 
nearest Leibnitz, 111 ; senses furnish 
material for, 220. 

Regula, non ex, jus sumi, sed ex jure 
quod est regulam fieri, maxim of 
Paulus, 486. 

Reinesius, 372. 

Relata, 235. 

Relations, a complex idea according to 
Locke, 5 ; of comparison, 144 ; of con- 
currence, 144 ; subjects of, 235 ; have 
something of essence of reason, 235 ; 
have foundations in things, 235 ; come 
from supreme reason, 235 ; may 
change, without change of subject, 
235 ; ideas of, their clearness, 236 ; 
of proportion, 258 ; of imperfect 
magnitude, 258; of origin, 258; of 
the family, 258; of consanguinity, 
259; alliance, 259; affinity, 259; nat- 
ural and moral, 260 ; by institution, 
260; itself often clearer than its 
ground, 265 ; value of knowing 
ground of, 265 ; dependent on Divine 
Mind, 277 ; knowledge of, largest 
field of human investigation, 432. 

Relative terms, what ? 235,236; which 
are usually deemed positives, 237. 

Religion demands unambiguous words, 
379. 

Remembrance, what? (subvenire) , 77, 
165. 

Reminiscence, 15,20, 77, 107 ; of Plato, 
15, 46 ; of what we know sometimes 
difficult, 20; Plato's doctrine of, de- 
nied, 21, 79, 80; how distinguished 
from other forms of thinking, 105. 

Resemblances, possibilities in, 356. 

Resistance in matter, is it invinci- 
ble? 122; arises in different ways, 
122, 123; defined, 122; comes from 



inertia, 123 ; comes from impetuos- 
ity of body, 123 ; comes from adhe- 
sion, 123. 

Resolutions, should be made when 
a man is in the midst of good im- 
pulses, 192; should be kept when 
their sensible reasons are only surd 
thoughts, 196. 

Respondentes, 478, 479. 

Rest, its privative nature discussed, 
131 ; cause of, 131. 

Restraint, what? 182. 

Restitutio in integrum, 534. 

Retention, a faculty of mind in con- 
templation, 142; in memory, 142, 
143. 

Revelation, what? 32; must be sure 
concerning, 554; original, 584; tra- 
ditional, 584 ; cannot go against clear 
evidence of reason, 584; cannot be 
received against intuitive knowl- 
edge, 584 ; determines against prob- 
ability, 585; supernatural reason, 
596; had external signs, 597; God 
sometimes illumines mind in, 597 ; 
defined, 598; judged by reason and 
Scripture, 598. 

Reveries, 165, 166. 

Reversal of viscera, 352. 

Revolution, a general, said to be im- 
minent through the spread of loose 
opinions, 536 ; will be a punishment 
and yet an advantage, 536. 

Reward, 260. 

Rhetoric, not truthful or calm, 389; 
though fallacious, popular, 389 ; cer- 
tain ornaments of, wisely employed, 
390. 

Rhine, 308. 

Richard First of England, exonerated 
from charge of murder by Old Man 
of the Mountain, 197. 

River changes its waters, yet is same 
river, 240. 

Rivers, their names, 308. 

Roberval, at eighty publishes his geom- 
etry, 463 ; his work on Euclid's ele- 
ments, 107, 473. 

Rod and sugar illustration, 470. 

Rohaut on motion, 233. 

Romans ii. 15, quoted, 43 ; 14 : 4, quoted, 
447. 



INDEX A 



811 



Romans who built, 99 ; excelled Greeks 

in law and arms, 415. 
Romulus, doubts about, 545. 
" Rorarins," 66. 
Rotbwelsch, its nature, 292. 
Round, why distant things seem so, 

120. 
Ruentis Acervi, problem of, 328. 
Ruhr, 303. 
Rules, sure when established on reason, 

45; good, their division, 486; when 

universal, 487; of jurisprudence, 

their uses, 493. 

Sagacity, 411, 555. 

Sancho Panza, saw Dulcinea by hear- 
say, 321. 

Sarmatian, 297; salt pits, 696. 

Satires, as historical material, 542. 

Satisfaction influences will, 188. 

Saxons, ancient books of, 295. 

Scaliger, Joseph, writes against math- 
ematicians, 93; Julius, his semina 
setemitatis, 43 ; dream of, 106. 

Scancliano, Count of, 398. 

Scarlet, like sound of trumpet, 128, 
321. 

Sceptics, 66, 420, 422. 

Scheubelius, his edition of Euclid, 403. 

Schilter, 295, 304. 

Schoenberg, 106. 

Scholastics, 55, 62, 66, 428, 503, 511 ; the 
question of immortality among, 52 ; 
their attempts at definition ridiculed 
by Locke, 320; sometimes present 
discussions of value, 494; their de 
constantia suljjecti, 516 ; abandoned 
infant damnation, 594. 

Science, demonstrative, founded on 
innate knowledge, 79 ; its content, 
326 ; historical, its content, 326 ; each 
has its prsecognita, 517 ; divided into 
three kinds, 621 ; each division may 
be made to absorb the others, 622 ; 
Nominalists on, 623; one for each 
truth, 623; like ocean, arbitrarily 
divided, 623; truths may be placed 
in different divisions, 623 ; a twofold 
division proposed, 623; a synthetic 
and practical part of, 624; an ana- 
lytic and practical part of, 624 ; how 
the ancient triple division should be 



understood, 625; civil division of, 
626 ; a third division, an index, pro- 
posed, 625. 

Scipio Ferreus, 571. 

Scriptures, Holy, may the literal sense 
of, ever be abandoned ? 589. 

Scythians, 297. 

Sea, noises of, as an illustration of in- 
sensible perceptions, 15, 48. 

" Search after Truth, The," 176. 

Seckendorf, nature of his work, 543, 
544. 

Secondary matter, not of utmost 
subtlety, 231 ; unity in, from con- 
spirant movements, 231; doctrine of 
monads throws much light upon, 231. 

Secondary qualities, can any neces- 
sary coexistence or incompatibility 
between them be known with cer- 
tainty? 461. 

Sectarianism, its strange influence, 
618. 

Self, dwells in us, 246 ; basis of phys- 
ical identities, 247; to be distin- 
guished from phenomenon . of self 
and pure consciousness, 247 ; phe- 
nomenon of, basis of personal iden- 
tity, 247. 

Semicircle, a centre of magnitude of, 
cannot be, 354. 

Semina setemitatis, 43. 

Semi-identicals, 492. 

Semi-pains, 170. 

Semi-pleasures, 170. 

Sendomir, Council of, 612. 

Sennertus, 487-489. 

Sensations, what? according to Locke, 
4 ; reminder of innate truths rather 
than proofs, 38; carried by nerves 
to brain, 121 ; how received by nerves 
or membranes, 122; different, pro- 
duced by same object, 133; what? 
165 ; of light, its genesis, 171 ; of 
heat, its genesis, 171 ; action in, 
220 : and imagination, difference 
between, 419, 422 ; may be same 
species with imagination, 422 ; give 
certainty, 511 ; scepticism regard- 
ing, impossible, 511; are "percep- 
tions of sensible things," 511; arise 
from external cause, 511, 512 ; jus- 
tify mathematical demonstrations, 



LEIBNITZ'S CRITIQUE OF LOCKE 



512; of the different organs -bear 
witness to each other, 512 ; beyond 
these, no knowledge but probabil- 
ity, 512. 

Sense-qualities, capable of real defini- 
tion, 17 ; give occasion to perceive 
ideas and truths, 82; not of arbi- 
trary constitution, 171. 

Senses, some ideas not from, 70 ; give 
confused ideas and truths, 82 ; do 
not give truths absolutely certain, 
470; are liable to illusion, 470. 

Sensible, qualities, pleonasm of per- 
ception in regard to, 324; species, 
381. 

Sentiments and beautiful sentences of 
authors, their use, 492. 

Serenus, 465. 

Series, a continued, to what extent 
in corporeal and intelligent worlds, 
332-334; certain, not compossible in 
universe, 334. 

Series, infinite, 424 ; expressive of pro- 
portion of square and circle, 425; 
can it be expressed in a finite quan- 
tity, 425 ; a, of syllogisms, 564. 

Sextus Pomponius, 241. 

Shadows interpenetrate, yet are dis- 
tinct, 238. 

Shame, what? 173. 

" Shepherd, The Extravagant," 389, 

Siam, King of, and existence of ice, 
530, 582. 

Sibyl, Cumsean, 598. 

Sifrid, Petri, 54G. 

Sight, object of, may not be in ex- 
istence when seen, 137; educated, 
of physicians, 392; neither wholly 
necessary, nor wholly voluntary, 
528. 

Signs, 621 ; and indications, medical, 
539. 

Simple ideas, 4 ; simple in appear- 
ance, 120 ; apperception does not 
divide them, 120; analyzed by rea- 
son, 121 ; which come by one sense 
only, 121 ; arranged according to 
means by which we perceive them, 
121; cannot have nominal defini- 
tions, 319. 

Simple modes, 164. 

Sins and duties, 261. 



Size, knowledge of, how acquired, 160. 

Sleep, 165, 166 ; does not arrest percep- 
tion, 112; if soul exist in, without 
perception, why not thought exist 
without perception ? 113 ; secured by 
division of attention, 115; dream- 
less, has a feeble consciousness, 
115. 

Sleidan, his forgetfulness, 114 ; Charles 
Fifth's opinion of, 543 ; nature of his 
work, 543. 

Slusins, his "pearls," 387, 465. 

Society, founded in nature and con- 
venience, 285, 286; not founded, as 
according to Hobbes, in the wicked- 
ness of the species, 285, 286. 

Sociniaus, 586, 589. 

Socrates, 495; in " Meno," 78; on 
afnuity of pleasure and pain, 170; 
his demon, 598. 

Solem dicere falsum aiidet, 156. 

Solidity, 220; how caused, 122; im- 
penetrability, a synonyme, 122, 123 ; 
sensible, 124; essential, what? 124; 
what? 125; perfect, an experiment 
regarding, 126. 

Solomon, quoted, 158. 

Solon, on parricide, 325. 

Something, the Eternal, is it a being, 
501. 

Sondem, its meaning, 366. 

Sophia of Russia, 601. 

Sophists, their obscurity of teaching 
ridiculed by Lucian, 378. 

Sorbonne, Casaubon's bon-mot con- 
cerning, 478. 

Sorites, 559, 561. 

Sorrow, what ? 172. 

Soul, in it a multitude of impressions, 
inarticulate like noise of waves, 11 ; 
always thinks, 11 ; more independent 
than thought, 15, 24 ; its thoughts 
not always distinct enough for re- 
membrance, 24 ; if passive, is with- 
out life, 25 ; its immortality not de- 
pendent on gracious miracle, 25, 53, 
63; its alleged reunion with ocean 
of Divinity, 53 ; its ineffaceable con- 
nection with organic body, 53; its 
immortality proved, 62 ; can it be 
annihilated? 62; the importance of 
its immateriality to religion and 



INDEX A 



813 



morality, 62, 63; Locke's view of 
its immateriality, 63 ; our thoughts 
and acts come from its depths, 
70; is its failure to perceive only 
a failure to remember what was 
learned formerly? 79; can a thing- 
be in, and yet not known when 
the soul has the capacity of know- 
ing it? 79; may not nature have 
concealed therein some original 
knowledge? 79; its properties and 
affections cannot be all considered 
at once, 79 ; may have possessions of 
which we have made no use, 80 ; has 
more than naked faculty towards in- 
nate truths, 81 ; has dispositions, ap- 
titudes, propensities toward innate 
truths, 81 ; nothing in, which will 
not be expressed by understanding, 
87 ; what it comprises, 111 ; never 
without perception, 112; continuity 
of its perceptions not disproved by 
dreamless men, 115; of child, what 
ideas in, before or at moment of un- 
ion with body, 117 ; its thoughts indis- 
tinct when a multitude of movements 
in brain, 117 ; it always expresses a 
body which is always impressed in 
an infinite multitude of ways, 117 ; 
perception in, of which it is not con- 
scious, 117; does not require that 
impressions be of a certain form and 
size to be perceived, 117 ; movements 
within, correspondent to circulatory 
and digestive movements in the 
body, 117 ; how do we know it al- 
ways thinks, 117 ; what is perceiva- 
ble is composed of what is not so, 
118 ; is to say that it thinks without 
consciousness, to say that it thinks 
unintelligibly? 118; not merely the, 
always thinks, but the man, 118 ; 
passive only in perception of simple 
ideas, 119; active in forming com- 
plex ideas, 119 ; impossible for it to 
think expressly upon all its thoughts, 
119 ; if thinking on all its thoughts, 
it would never pass to a new thought, 
119 ; its connection with body, 138 ; 
vegetable, 141 ; a simple substance 
or monad, 147; while representing 
body, preserves its own perfections, 



181 ; dependent on body, 181 ; in 
voluntary acts body dependent met- 
aphysically on it, 182; a living 
mirror, 219 ; a " separate,' ' inconceiv- 
able, 220, 221 ; thinks and feels al- 
ways, 230 ; never leaves entirely and 
at once the body, 230; in animals 
and vegetables secures their iden- 
tity, 241 ; cannot wholly leave body, 
242 ; keeps even in death an organ- 
ized body part of preceding, 242; 
basis of identity, 242; no transmi- 
gration of, but transformation, 242; 
should doctrine of its immaterial- 
ity be received on faith ? 429 ; im- 
materiality of soul not the only 
basis of morality, 429; produces 
pleasure or pain in conformity to 
what takes place in matter, 431 ; is 
there, if it is not perceived? 490. 

Souls, always joined to a body, 52, 
113; of brutes, their conservation 
does not require metempsychosis, 
53; not perishable, 68, 166; not 
absurd to suppose that there are 
truths in, which may yet be devel- 
oped, 80; capable not merely of 
knowing innate truths, but of find- 
ing them, 80 ; all differ, but not spe- 
cifically, 110 ; never without organs, 
220 ; never without sensations, 220 ; 
a kind of movement attributable to, 
231 ; change nothing in the force of 
bodies nor in their direction, 233; 
as primitive entelechies are infinite, 
348. 

Soul and body, independent, yet mutu- 
ally obedient, 68 ; difficulty regard- 
ing union of, removed by doctrine 
of monads, 510, 511; harmony of, 
553. 

" Soul and machine," 348, 349. 

Sound, heard by teeth and vertex, 122. 

Space, views of Locke and Leibnitz 
regarding, 12; full of infinitely 
divisible matter, 54; without body, 
a fiction of philosophers, 114; " full 
of cubes?" 124; and solidity, are 
they two? 128; a kind of order, 128 ; 
defined, 153; indicates the possible 
as well as the actual, 158; has its 
reality from God, 159 ; infinite, no 



LEIBNITZ'S CRITIQUE OF LOCKE 



idea of, 163 ; a vacuum in, consid- 
ered, 16, 126, 481. 

Spain, castles in, 166. 

Species, immission of, a theory of self- 
perception, 20 ; intentional, 55, 381 ; 
names of, originally given to individ- 
uals, 308 ; receive names of genera, 
308 ; ascend from, to genera, 309 ; can 
be infinitely varied, 314; is the es- 
sence or idea of, factitious or existent 
in nature ? 314 ; are they dependent 
entirely on name, 315; its limits, 
usually fixed by nature, may be 
arbitrary, 328 ; logical, will never be 
found, 331, 332 ; cannot be founded 
on essence or interior constitution, 
332; is their foundation in nature 
or in naming ? 335 ; an ambiguity in 
connection with terms, 335, 336 ; 
what can after change be returned 
to its first form, has preserved its 
first, 336 ; in organized bodies, 336 ; 
determined by generation, 336 ; what 
constitutes human, 336; all, truth- 
fully distinguished, have founda- 
tions in nature, 337; in botany, 
337; assumptions involved in the 
supposition that, are dependent on 
model essences, 338 ; may there 
not he a common internal specific 
mark of? 339 ; if dependent on 
propagation, questions concerning, 
343, 344 ; which are not unum per 
se, 348 ; devised by the ignorant, but 
constantly under scientific correc- 
tion, 349, 350; if work of nature, 
why such differing conceptions of? 
350; may have real essences inde- 
pendent of our knowledge, 353 ; 
much alike, seldom occur together, 
353 ; in what cases passage between 
may be insensible, 353; to what 
extent we can combine ideas to 
produce, 353, 354 ; definition of, 
depends on ability and industry 
of definer, 354 ; conceptions of, may 
vary, 355 ; may be good and natural, 
though not best and most natural, 
355; men determine name but not, 
357; mathematical, 357; physical, 
357; accidental changes do not af- 
fect, 358 ; provisional mark of, 358 ; 



do the house dogs of England and 
those of Boulogne belong to different, 
358 ; infima, 358 ; dog and elephant, 
of different, 358 ; of time-pieces, how 
determined, 359 ; all men of one, 359 ; 
do not depend on opinion, 360 ; exist 
in nature, 360; purely logical, 360; 
purely physical, 360 ; founded on 
specific civil differences, 360 ; nomi- 
nal, 360; legal, 360; of artificial 
things, the hesitation to admit them 
into the Predicamental Tables, 361 ; 
a rule for determining, practically, 
361; sensible, 381; do we wrongly 
think that nature fixed limits to 
each by specific essence, and that 
this follows some specific name ? 386 ; 
a dictionary of simple ideas observed 
in each individual of, desiderated, 
394; description of, is natural his- 
tory, 395 ; is being completed by 
degrees, 395 ; why retarded, 395 ; 
will be defined provisionally only 
by definitions of genera, 457 ; medi- 
ate, why kept from our observation, 
552 ; connection of, 552. 

Speculative discussion usually affords 
two sides, 378. 

Speech, the instrument and bond of 
society, 285 ; monkeys said to have 
organs of, 286; might consist of 
musical tones, 287 ; by words more 
suited to man's original simplicity, 
287 ; organs of, not in birds who use 
words, 287; man alone can employ 
organs of, 287. 

Spendthrift, his undue estimate of 
"advantage of the present," 209. 

Spider's voracity, 91. 

Spinoza, " the subtle Jew," cautiously 
quoted, 526 ; life of, exemplary, 535. 

Spinozists, Leibnitz's relation to, 69; 
their views of God, 69 ; their views 
of final causes, 69. 

Spirit, existence of, more certain than 
that of sensible objects, 229 ; not " in 
loco seel in aliquo ubi," the expres- 
sion challenged, 230 ; their " ubiety " 
detailed, 230 ; cannot be stripped of 
perceptions of past existence, 249; 
has presentiments which can he de- 
veloped, 249 ; an illustration of a 



INDEX A 



word passing from a sensible origin 
ta a signification more abstruse, 
289. 

Spirits, united to some organic body, 
159; related to otber bodies, 159; 
related to space, 159; can perbaps 
assume suitable organs of sensation, 
228 ; can operate only where they 
are, 229 ; active power perbaps, the 
proper attribute of, 233; created, 
not totally separate from passive 
matter, 234; in the future state, 
possess very perfect organs, 393 ; 
influence matter, 440; form a kind 
of State under God, 441. 

Spring, a mineral, 240. 

" Square is not a circle " : is the idea 
innate ? 83, 84. 

Squaremay be known by child, though 
its incommensurability with its diag- 
onal unknown, 100. 

" Square equal to circle," how nearly 
done, 424. 

Stabbing, English opinion of, 326. 

" State of Vision " of theologians, 429. 

Stegmann, Christopher, a Socinian, 
585. [585. 

Stegmann, Joshua, an anti-Socinian, 

Stoics, their prolepses, 43; their views 
of the passions, 172; their "wise 
man alone free," 179; on future life 
and virtue, 208. 

Srop777, 91. 

Strabo, 345. 

Strauchius, 365. 

Street-porter surpasses a statesman in 
determining the weight of a burden, 
273. 

Strigil, curry-comb, 394. 

Study, 165, 166; reasons for aversion 
to, 609. 

Stupidity, 146. 

Suarez, 494. 

Sub-exceptions, 480. 

Subscription to symbols, 619. 

Substance, its existence dependent on 
activity, 11 ; 'a, whose knowledge 
and power are infinite should be 
honoured,' au innate principle, 23; 
how perceived, 24; Locke's view of, 
57, 58 ; activity belongs to its es- 
sence, 60 ; immaterial, necessary to 



thought, 62 ; unities of, 66 ; Locke 
denies we have idea of, 105 ; reflec- 
tion discovers idea of, 105; once in 
action always so, 111 ; has a degree 
of liquidity, 111 ; activity of, implies 
activity of soul, 112 ; Locke's defini- 
tion, 148; idea of, not obscure, 148; 
division of, 148 ; may God, finite 
spirits, and matter be modifications 
of a common ? 153 ; do accidents 
subsist in ? 154 ; divergency of 
opinion between Locke and Leib- 
nitz upon, 154; that which is active, 
218; one created, cannot influence 
another, 218; is idea of, due to in- 
advertence ? 225 ; is assumption of 
substratum in, unreasonable ? 225 ; 
whence our ignorance of substance ? 
227 ; Locke's opinion of, 234 ; if one 
add a quality to the idea of a, does 
he change essence of substance, or 
perfect bis idea of it? 385; an 
allegation that ideas of, being fan- 
cies, prevent advance in knowl- 
edge, 389; the visible in, gives first 
ideas, 392 ; knowledge of internal 
constitution of, necessary to ulterior 
knowledge both of qualities and of 
accidents, 457, 458; can it be multi- 
plied when the individual essence 
does not exist ? 589 ; in theology, 612. 

Substances, according to Locke, 5; 
simple, created, always joined to a 
body, 52 ; never naturally separated 
from matter, 63; universally differ- 
ent, 110 ; internal vortices of, cannot 
be stopped, 112; 'these machines 
are,' 280; their definition, 317; gen- 
era and species, ouly sorts of, 330; 
ideas of individual names usually 
confined to ideas of, 361 ; perfect, to 
be distinguished from {aggregata) 
assemblages of substances, 361 ; di- 
recting or characteristic qualities in, 
392 ; names of, say more than defini- 
tion, 393, 394; definitions of, arrived 
at by study of natural history, 394 ; 
do not have their qualities inde- 
pendent of other substances, 461. 

Substratum, 5. 

Subvenire, 77. 

Succedaneum, 417. 



LEIBNITZ'S CRITIQUE OF LOCKE 



" Summa Theologize " of Fabri, 586. 

Summa rerum, 215, 610. 

2ij/j,Trvoia navTa, phrase of Hippo- 
crates, 48. 

Sun, birds iu the, intelligent, 244. 

Suppressions, internal, 77. 

Surd thoughts, 191, 193, 196, 198, 210, 
265, 270, 287. 

Suspension of desire, 202. 

Sweden, theological authority in, 611. 

Swedish youth, a prodigy in numbers, 
78, 393. 

Sweetness different from bitterness, a 
fact of primitive experience, 23. 

Swiss Confession, 612. 

Syllogism, when terms equivocal, 484; 
does it present only a single exam- 
ple? 557, 562; does it help mind? 
557, 558; used on authority, 557; 
if we can reason without it, what 
then ? 557, 563 ; its forms, 557 ; when 
to be used, 557, 562, 563; cannot 
show connection of mediate ideas, 
558 ; its use confined to the schools, 
558 ; a possible use for, 558 ; its in- 
utility, 558 ; serves as spectacles, 559 ; 
Leibnitz's view of, 559 ; the scholas- 
tic, not often employed, 559; almost 
important and beautiful discovery, 
559; a universal mathematics, 559; 
contains an infallible art, 559 ; cate- 
gorical (simple and complex), 560; 
hypothetical, 560; disjunctive, 560; 
like counting on the fingers, 561, 
562 ; it may be trifling, 562 ; useful 
in probabilities, 564, 565 ; its use in 
invention questioned, 565 ; its scope 
as "formal argumentation," 565 ; 
Locke's visible mistake about, 567 ; 
does not require a universal proposi- 
tion for its validity, 567 ; a transpo- 
sition of premises proposed, 568; 
begins with universal proposition as 
more didactic, 568 ; its doctrine de- 
pends on " de continente et. con- 
tent*)," 569; single, people of a, 
608. 

Symbolic books, the propriety of 
swearing to adhere to, 619. 

Sympathy, 391. 

Symptom, 113. 

Syncategorematic, 161. 



Syncretists, 537. 

Synthesis, often leads to beautiful 

truths, 412. 
Syrus, Publilius, 492. 

Tabula rasa, is the mind originally 
a? 4, 10, 15, 42, 65, 105 ; of Aristotle, 
38 ; a fiction based on imperfect no- 
tions of philosophers, 109, 110; if 
soul a, then when ideas taken away 
there is nothing, 110 ; notion of, rests 
really on corporality of soul, 111. 

Tacitus, 91. 

Taking words for things, 484. 

Tartar, 297. 

Taste, felt by nose, 122. 

Tastes, confused perceptions, 208; how 
to be treated, 208 ; both of palate 
and of soul can be changed, 216. 

Teaching, employs general proposi- 
tions, 475. 

Tendency, 174; included in power, 
224. 

Tenderness, what? 223. 

Tentamen, 38. 

Terence, quoted, 459, 492. 

Terms, peculiar to each language, 222 ; 
dependent on change of custom, 222 ; 
general, their place in language, 288 ; 
did language originate in, 288 ; how 
arrived at, 309, 310; abstract and 
concrete, 368 ; abstract, distinct, 
368 ; can they be affirmed of each 
other? 368, 369; abstract, logical, 
368, 369; real, 368, 369; are they 
confined to schools, 369 ; a chaos of, 
much time lost over, 442. 

Tertullian, his prsescriptiones, 531 ; 
"the impossible must be believed," 
582. 

Testimony, may secure moral certi- 
tude, 247 ; and opinion compared, 
530 ; its force diminished as it is re- 
moved from the original statement, 
541 ; the value of contemporary, 
541 ; subjects about which it cannot 
be obtained, 548. 

Tetragonism, 75. 

Teutonic language and antiquities 
enter into European history, 304. 

Thales of Miletus, 463. 

" Theatrum Vitas Humanse," 548. 



817 



Theme, incomplex, 39S ; complex, 398. 

Themes, which are between ideas and 
propositions, 398. 

Theogony, 361. 

Theology, Christian, ridiculed by one 
who persisted in explaining its terms 
according to their original force, 
290 ; based upon revelation, 474 ; 
unites with it ' natural ' theology, 
474; natural, "the axioms of ex- 
ternal reason," 474; founded on 
" the veracity and attributes of 
God," 474; natural, theoretical or 
metaphysics, practical or ethics, 
496 ; reason in, 585 ; logical necessity 
accepted in, 588 ; physical necessity 
not sufficient to refute a miracle, 
588; a conclusion in, is it to be 
judged by its terms or means of 
proof? 588; as an indicial term, 627. 

Theophilus, why assumed, 69. 

The'otisque, 294. 

' Therefore,' its use, 564. 

Theresa, St., 600. 

Theseus, ship of, 240. 

Thieving, why praised by Spartans, 
263. 

Things, not perceived, should not 
therefore be denied, 24 ; of which 
we are not conscious are neither in 
soul nor body, 51; " themselves," 59; 
cannot be and not be at same time, 
are there some to whom this axiom 
is not known ? 72, 83 ; uniform ab- 
stractions, 110; substantial, have 
each characteristic relations to each 
other? 110 ; of the same kind, yet 
not perfectly alike, 238; "identical 
with a third thing are identical with 
one another," denied by some in 
theology, 586. 

"Think, I, therefore I am," 410, 469. 

Thinking, art of, in time of need, 214 ; 
its elements not yet found, 214; 
not mnemonics, 214 ; -being, can it 
come from non-thinking? 505; not 
from the spiritualization of matter 
by minute division, 505 ; not by its 
configuration, 506 ; not by its organ- 
ization, 506. 

"Thirteen," 283. 

Thomasius, Jacob, 606. 
3g 



Thorn, Council of, 613. 

Thought, immediate objects of, 109; 
mediate objects of, 109; external 
immediate object of, God, 109; in- 
ternal immediate object of, soul, 
109; is what? 135,178; past persists 
or memory could not preserve it, 
143; an essential act of soul, 166; 
what animals have no, 178; trains 
of, 182 ; pertains to mind, 218; only 
a passive power, 219; should not 
think of, apart from things senses 
furnish, 220. 

Thoughts, and acts, all from depths 
of soul, 70; external senses in part 
causes of, 70 ; are acts, 84 ; distin- 
guished from ideas, 119 ; we are 
never without, 119; correspond to 
sensation, 119; in general, 119; re- 
markable, 119; involuntary, 182; 
partly from external objects, 182; 
from remaining impressions, 182. 

"Three, is as much as two and one," 
a definition, 410 ; conceals an intui- 
tive conviction that the ideas are 
possible, 410. 

Time, " a kind of order," 128 ; is num- 
ber not measure of motion, 157 ; the 
vacuum in, what it shows, 157 ; has 
its reality from God, 159; a vacuum 
in, concealed, 159; distinguished, 
238. 

Tobacco-smoking, its spread illustra- 
tive of spread of tradition, 72 ; illus- 
trative of habit, 216. 

Topics (argumenta) , 398 ; explain, 398 ; 
prove, 398 ; of Aristotle, 498, 541. 

Torricelli, tube of, 127. 

Touch, qualities of, are modifications 
of resistance or solidity, 122. 

Traction, in bodies which do not touch, 
125, 127. 

Trades, how best taught, 628. 

Tranquil times of progress looked for- 
ward to, 437. 

Transmigration, Van Helmont's idea 
of, 242; held by Rabbins, 242; 
distinguishable from transforma- 
tion, 242; in what sense may be 
held, 242; in what sense possible, 
243; not conformed to order of 
things, 243; of human soul into a 



818 



LEIBNITZ'S CRITIQUE OF LOCKE 



hog, does it make a man? 243; in- 
volves no apparent absurdity, 249; 
of immaterial substance without 
same consciousness does not con- 
vey same personality, 249. 

Transparency, artificial, produced by 
rapid rotation of a cog-wheel, illus- 
trative of confused sensitive percep- 
tions, 459. 

Travel, books of, their uses, 548. 

Trebeta and Treves, 546. 

Trent, Council of, 612. 

Trimalchio, 204. 

Trithemius, 546. 

Tropical use of language, 271. 

True and false, belong to propositions, 
281; how applicable to ideas, 281. 

True, the, may be drawn from the 
false, 565. 

Truth, necessary, alone capable of 
proof, 3; what? 4; not founded on 
experience, 11 ; seeker of, described, 
31 ; he who does not seek it sin- 
cerely himself dictates to others, 
31; unknown to brutes, 44; imme- 
diate to understanding and always 
present, 45 ; not established by long- 
past experience, 45 ; from under- 
standing alone, 81; mind source of, 
81 ; cannot be innate unless its ideas 
are innate, 84; a, may be known 
without knowing all about it, 100; 
though natural, not known from 
cradle, 100 ; nothing stronger to 
influence men than, 198 ; of sensible 
thiugs only in connection of phe- 
nomena, 421; how distinguished 
from dreams, 421 ; not a supreme 
attraction to man, 437 ; what is 
it? 449; is it in agreement or disa- 
greement of signs ? 449, 450 ; does it 
lie in words ? 450, 451 ; Hobbes' view 
of, 450 ; as to its division into men- 
tal or nominal, 451 ; why not have 
literal too ? 451 ; its definition as 
lying between objects of ideas, 
451 ; common to us with God and 
angels, 451 ; its provisional indica- 
tion, 451 ; moral, what ? 452 ; meta- 
physical, what? 452; lies in the 
correspondence of propositions in 
the mind with the things in ques- 



tion, 452; certainty of, 454; is there 
theological, opposed to philosophi- 
cal, each being true ? 581 ; how 
judged of, 611. 

Truths, speculative and practical, the 
same, 23 ; do all depend on experi- 
ence ? 43 ; necessary, of mathematics 
do not depend on examples, 43 ; yet 
such truths may be evolved by the 
senses, 44; necessary, how discov- 
ered, 44 ; necessary, 68 ; of fact, 
69 ; origin of, 71 ; necessary, their 
origin, 71; particular, sooner per- 
ceived, 74 ; their proof dependent on 
more general, 74 ; of arithmetic and 
geometry innate, 76 ; imprinted on 
the soul, yet not always perceived, 
77 ; of fact, 78 ; necessary, 78 ; are 
innate which can be drawn from 
primitive innate truths, 79; are 
innate when their proof lies in what 
is within and not in what is given by 
experience, 80; either necessary, or 
stores of experience, 81 ; universal, 
we cannot be assured of by induc- 
tion, 81 ; have their necessity in 
reason, 81 ; necessary, their source 
in intellectual ideas, 82 ; are they 
subsequent to ideas? 82; express 
knowledge of, how subsequent to 
express knowledge of ideas, 82 ; that 
are within us are habitudes or dis- 
positions, not thoughts, 84 ; of rea- 
son not so evident as immediate or 
identical truths, 86 ; opinions taken 
as, which are only effects of custom 
and credulity, 98, 99. 

Truths, individual, only given by 
senses, 11 ; knowledge of, not in- 
nate, 21; actual consideration of, 
not innate, 21 ; contingent, how 
they come to us, 22; of fact, how 
they come to us, 22; necessary 
derivative, what they depend on, 
22 ; primitive, their source, 22 ; 
dependent on divine mind, 277 ; 
negative, 289; primitive, known by 
intuition, 404; divided into those 
of reason and those of fact, 404 ; of 
reason, identical, 404; affirmative 
and negative, 404, 405; identical, 
negative, which belong to principle 



INDEX A 



819 



of contradiction, 405 ; primitive, of 
fact, are immediate internal experi- 
ences of an immediateness of feel- 
ing, 410 ; not to be confounded with 
their expressions, 451 ; general, their 
establishment more important than 
resolution of particular cases, 467; 
their natural and historical order, 
470 ; why many pass as self-evident, 
yet are capable of farther reduction, 
473; of experience and truths of 
pure reason compared, 493 ; eternal, 
at bottom conditional, 515; neces- 
sary, are determining reasons and 
regulating principles of existence, 
516; anterior to existence of con- 
tingent beings, 516; grounded in 
necessary substance, 517 ; in mind 
originally not as propositions but 
as sources of judgment, 517. 

Tulpius on man-like ape, 244. 

Tunica, cloak, 394. 

" Two and two are four," its demon- 
stration, 472. 

" Two homogeneous magnitudes are 
equal when one is neither greater 
nor smaller than the other " : an ax- 
iom of Euclid and Archimedes, 473. 

Ubiety, circumscriptive, 230; defini- 
tive, 230 ; repletive, 230. 

Unconscious pain, 195. 

Understand, not to, a thing, no ground 
for denial of its existence, 60; to, 
what? 177. 

Understanding, "to be in," according 
to Locke, and according to Leibnitz, 
81 ; a resemblance to, 147 ; adds re- 
lations, 148 ; the origin of all things, 
148 ; what ? 177 ; animals have none, 
178; corresponds to intellectus, 178; 
its action intellection, 178; guardedly 
called a faculty of soul, 178; with- 
out freedom of no use, 216. 

Uneasiness, 49, 171, 172 ; as a stimu- 
lus, 168; expressed by " inquie- 
tude," rather than "chagrin," 169; 
its influence on will, 18S; may be 
an insensible perception, 188; not 
always a displeasure, 188; arises 
from nature's efforts to put herself 
more at ease, 194 ; determines in 



cases apparently indifferent, 194; 
the field of a series of little suc- 
cesses which afford pleasure, 194; 
not incompatible with happiness, 
194; consists in feeling without 
knowing it, 194 ; more pressing not 
always prevalent with will, 200. 

Unhappiness, the result of false judg- 
ments, 209. 

Unities of substance, 66. 

Unity of languages can only be at- 
tributed to migration of peoples, 
297. 

Unity, perfect, not secured by homo- 
geneity, reserved to animated bodies, 
362. 

Universality, never proved by experi- 
ence, 22 ; in what it consists, 567. 

Universals, are they real? 313; com- 
prise (in form) particulars, 567. 

Unpremeditated actions, result of 
minute perceptions, 116. 

Unruhe, term applied to pendulum, 
171. 

Unum ex primis cognitis inter ter- 
minos complexos, 469. 

Urim and Thummim, early teachings 
a sort of, 611. 

"Utilitate Credendi, De," of Augus- 
tine, 616. 

" Utriusque," 227. 

Vacuum, 65 ; Locke and Leibnitz upon, 
16; is it necessary to motion? 53; 
excluded, 68 ; perfect cannot be 
proved by experiment, 127 ; would 
opposite sides touch in ? 155 ; in 
time and space, 159; abhorrence of, 
can be soundly understood, 381 ; 
denied by Descartes and Leibnitz, 
483 ; in forms or species, 552. 

Valla, Laurentius on the Jurists, 415. 

Van Helmont on transmigration, 242. 

Vandal king, 99. 

Vayer, La Mothe le, 593. 

Vedelius, his " Rationale Theologi- 
cmn," 587, 588, 595. 

Vega, Garcilasso de la, 89. 

Vegetative souls, not to be lightly dis- 
carded, 380, 381. 

Velleity, 168, 169. 

Velleiie, what? 188. 



820 



LEIBNITZ'S CRITIQUE OF LOCKE 



Venus Urania and the bastard Venus, 
390. 

Vergil, 200, 415, 598; on the praise of 
virtue, 263; quoted by the Priscil- 
lianists, 345; quoted by Coperni- 
cans, 614. 

Versura, 326. 

Vice, by what standard adjudged a, 
261, 263; its relation to sin, 262. 

Vieta, extended algebra, 468, 573. 

Vincent de Lerins, his " Commonito- 
rium," 617. 

" Vindication of Doctrine of Trinity," 
by Stillingfleet, 56 ; Locke's opin- 
ions examined in, 56; ensuing con- 
troversy, 57. 

Viottus, 520. 

Vires centripetse, 132. 

Virgil of Salzburgh, 443. 

"Virtually," defined, 78. 

Virtue, its meanings, 95 ; the philo- 
sophic notions of, 96 ; Aristotle's 
definition of, 96 ; a pleasure of mind, 
167 ; its success if fashionable for a 
day, 198 ; is useful, 261 ; not depen- 
dent on opinion, 262; and vice, are 
they founded on tacit consent ? 262 ; 
what is generally praised is usually 
worthy of praise in some respects, 
263; the term, and that of praise 
often applied to same quality, 263, 
264; praise attributed to, in Vergil 
and Cicero, 263, 264 ; is it that which 
is praised, or that which is worthy 
of praise ? 264 ; called ' honesty ' by 
ancients, 264. 

Visions, what ? 166 ; divine, 166 ; state 
of, 429. 

Vivacity of mind, what? 143. 

Vives, Ludovicus, 591. 

Vladislas, king of Poland, 612. 

Volition, what? 177; a result of con- 
flict of perceptions and inclinations, 
199 ; has at bottom perceptions only 
perceptible in mass, 199 ; most press- 
ing uneasiness not always prevalent 
to secure, 200 ; obeys sometimes a 
'compound direction,' 200; finally 
determined by result of tendencies, 
200; mind can employ the dichoto- 
mies to vary influence, 200. 

Voluntary, defined, 177 ; and free, 187 ; 



aud involuntary not distinguishable, 
553. 
Vulcan's buckler, 479. 

Water, its apparent compression due 
to air, 126: changed into wine on 
Christmas Eve, 470. 

Waterfall, why unconscious of its 
noise? 47. 

Water-mill, 117. 

Weigel, his moral diagrams, 435. 

"Whatever is, is" not universally 
known, 72. 

"White is not red," 83. 

Whiteness, what ? 163. 

"Whole, the, is equal to its parts," 
not expressly used by Euclid, 471 ; 
its limitations, 471. 

Wilkins, Bishop, his artificial lan- 
guage, 292. 

Will, not exclusively influenced by 
assurance of greater good, 26 ; influ- 
enced by present unrest accompa- 
nied by desire, 26; what? 177; and 
power united, action follows, 177 ; 
" is free," phrase discussed, 185, 186 ; 
and understanding, relation of, 185 ; 
may suspend its exercise, 186; acts 
in advance of, may influence, 187; 
action of, determined by what 
pleases, 188; what determines the, 
188; and desire distinct, 188; what 
determines, not greater good, 188; 
some actual uneasiness, 188 ; great- 
est good fails to influence, because 
not strongly sensible to us, 192 ; re- 
moval of present pain determines 
it, 194; why so little swayed by 
thoughts of future life, 196 ; and 
desire, why confounded, 198; its 
intelligent determination desirable, 
204 ; its indifference an imperfection, 
204 ; absolute indifference never pos- 
sible, 204; in cases of seeming indif- 
ference it is yet determined by a 
concurrence of internal dispositions 
and external insensible impressions, 
204; determination of, useful, 205; 
secures effective choice, 205 ; deter- 
mination of, if it exists in anything 
but final choice, not free, 205 ; com- 
plete in superior beings, yet they not 



INDEX A 



less free, 205 ; in God secured by 
what is best, 206; in God not fixed 
by necessity, 206; secured by incli- 
nation, 206; to the best, is freedom, 
206; should be determined by hap- 
piness in general, 206; should be 
determined by particular goods only 
when found agreeing with our true 
happiness, 206; and taste under one 
control, 207 ; acts by present percep- 
tions, 211 ; acts by present image of 
the future, 211 ; acts by discomfort 
of opposition to a resolution or 
habit, 212. 

Wisdom, the science of happiness, 
377. 

Witt, Pensionary De, 426; on Annu- 
ities, 540. 

Wittemberg, 611. 

Witty sayings not to be too rigorously 
treated, 144. 

Worcester, Bishop of, Locke's reply 
to second letter of, quoted, 54, 55; 
on immortality of soul, 58. 

Words, the twofold abuse of, 270 ; re- 
present and explain ideas, 285 ; trans- 
ferred from origin in simple ideas 
to more abstruse significations, 289; 
their tropical signification depends 
on analogy between the sensible and 
non-sensible, 290 ; are the meanings 
of, arbitrary? 292; the use of, im- 
plies that speaker has ideas, 305 ; 
may sometimes be those of another 
than speaker, 305; hollow use of, 
305 ; speaker of, means something 
general, 305; men often think more 
of, than things, 305 ; connect them- 
selves with ideas and things, 305, 
306 ; often secure attention to exclu- 
sion of things, 305 ; are supposed to 
have a secret relation to another's 
ideas, and to things, 305; form 
of, what? 305; are often parrot's 
sounds, 305 ; as applied to simple 
ideas and modes, 306; as applied to 
substances, 306; spoken of some- 
times in a material way, 306 ; largest 
number of, are general terms, 307 ; 
originally general terms, 308; how 
they become general, 309 ; genus and 
difference employed in defining, 312 ; 



dichotomous definitions of, best, 312 ; 
their use, 356, 357 ; their analysis 
shows best the workings of the 
understanding, 368; their imperfec- 
tions, 369; double use of, 369, 370; 
civil use of, 370 ; philosophic use of, 
370 ; are ?iotse for us and others, 370 ; 
cases in which it is difficult to learn 
and to retain ideas of, 370; how 
their defects may be remedied, 373; 
have a double relation to things 
signified, 374; those which indicate 
simple ideas not wholly unequivo- 
cal, 375 ; those which indicate simple 
modes least doubtful, 375 ; act as a 
medium between understanding and 
thing, 375 ; removal of imperfections 
of, would lessen disputes, 375; re- 
form in use of, suggested, 375; 
uncertainty in regard of, should pro- 
duce modesty in controversy, 376; 
have changed much in Latin and 
other languages, 376 ; have changed 
little in Greek authors, 376 ; Italian, 
have not changed so much as French, 
376; imperfections of, arising from 
intention and negligence, 376; are 
abused, when we attach no clear 
ideas to, 376 ; there are, which never 
had a definite idea, 377 ; there are, 
which have lost their first idea, 377 ; 
insignificant, not many, 377 ; abused, 
because we learn them before their 
ideas, 377; bad use of, leads to mis- 
construction, 378 ; abuse of, from in- 
constancy of use, 378; inconstancy 
of use in, dependent on inadvertence, 
378; abuse of, through affected ob- 
scurity, 378 ; abused, when we take 
them for things, 379; pardonable 
and praiseworthy obscurities of, 379 ; 
not so much taken for things as be- 
lieved to be what they are not, 380 ; 
are abused, when used for things 
they cannot signify, 384; are they 
abused when applied to complex 
ideas as if these had a real essence 
on which the properties depend? 
384 ; abused when we attach certain 
ideas to them, and then suppose 
that everybody accepts our mean- 
ings, 387; their uses. 388; corre- 



822 



LEIBNITZ'S CRITIQUE OE LOCKE 



sponding defects, 388; abuse of, in 
figurative terms and allusions, 389 ; 
remedies for tlie philosophic abuse 
of, 390 ; always use, with ideas, 391 ; 
ideas of, applied to modes should be 
more determined and those of sub- 
stance carefully conformed to what 
exists, 391 ; usage should be re- 
garded in, 391; when new are used, 
or old ones in a new sense, the 
sense in which taken should be 
declared, 391 ; for simple ideas are 
explained by synonyms or by show- 
ing the thing, 391 ; conveying mixed 
modes are explained by definition, 
391 ; diagrams remedy uncertainty 
of, 435 ; put in place of things, 451. 



World, ideal, 326; existing, 326. 
Wormwoods, Bauhins on, 308. 
Worsley, 259. 
Writing, characters in, what ? 512. 

Ximenes, Cardinal, his cure by Moor- 
ish woman, 623. 

Yellowness not sweetness, 83. 

fyrovfiivri, Aristotle's, 495. 

Zopyra, 43. 

Zwinger, " Theatrum Vitse Humanse," 

548. 
Zwingli, on salvation of heathen, 

595. 
Zwinarlians, 589. 



INDEX B 

TO THE APPENDIX 



Act, to, a mark of substance, 671. 

Acta Eruditorum Lipsiensium, 699, 
705. 

Action, moving {actio inotrix, V action 
motrice), 661, 703; moving, general 
rule of, 661 ; and reaction, law of, 
689; composed of body, time, and 
force, 702. 

"Agreement, natural," as a theory 
explanatory of relation of body and 
soul, 709. 

Agrippa, his angelic obstetrician, 646. 

Anaxagoras, his sophism concerning 
black snow, 639. 

Angle, the right, the determinate of 
all angles, 694. 

Antitypy, avriTvirla., 637,645, 647, 648. 

Ape and the infant Christian of Den- 
mark, 697. 

Airopa, 657. 

Apparent phenomena, what ? 719. 

Archjeus (hylarchic principle) of 
Henry More, 679. 

Ariosto, his hippogryphs, 718. 

Aristotle, his ^vctikt] 'A/cp<Wts, " Phys. 
Auditus," 634, 641 ; his teachings 
compatible with Reformed Philoso- 
phy, 634, 635, 636, 645; "the irrec- 
oncilable," 634; his view of "vac- 
uum," 634, 699; his "Ethics," 635 ; 
his "Logic," 635; his "Metaphys- 
ics," 635, 642; his " Physics," 635; 
his meaning perverted by the scho- 
lastics especially in physics, 635, 636; 
incorrectly represented to say that 
geometry was not a science, 642; 
his "Analytics," 642; places origin 
of motion in mind, 643, 651 ; how he 
regards form as a cause of motion, 



643 ; does not employ the " substan- 
tial forms" of the Scholastics, 643; 
ascends to the First Mover, 643 ; his 
definition of time, 645; his "pri- 
mary matter," 651; his " vortices," 
651; adds intelligence only to prin- 
cipal rings of his vortices, 651, 680; 
his geocentricism, 651; his errors 
extenuated, 651 ; his entelechies, 
ivreXexetai, 671, 699, 701, 712. 

Atheism, its prevalence in Leibnitz's 
time, 648; a philosophy which af- 
forded a unique plank by which 
men could save themselves in the 
shipwreck of impending, 648. 

Atoms, there are no, 652; defined, 
653 ; of any figure, 653 ; it is impos- 
sible for all bodies to consist of, 
demonstrated, 653; scholium to 
demonstration against, 654; appen- 
dix to demonstration against, 656; 
do not exist, since their existence 
would make change of motion take 
place by leaps, 669, 686; do not ex- 
ist, since curvilinear motion is com- 
posed of rectilinear motions, 690; 
theory of, opposed to subtlety of na- 
ture, 712. 

Averroists, on " interminate " quan- 
tity of matter, 637. 

Bagheminus, as a writer, 632. 

Basnage deBeauval, his " Histoire des 
Ouvrages des Savants," 706. 

Bayle, Leibnitz's explanation of the 
difficulties presented by, to the the- 
ory of pre-established harmony, 706. 

Being, A Unique, 692; how He rules 
the world, 692 ; is ultimate reason of 



8JJ3 



824 



LEIBNITZ'S CRITIQUE OF LOCKE 



things, 692 ; His existence not to be 
escaped by assuming eternity of the 
world, 692, 693 ; He exists of meta- 
physical necessity, 693; is free yet 
determined, 695; in Him essences 
and eternal truths exist, 695; the 
connection of all things with each 
other proves Him their one source, 
696 ; that the most perfect, exists, 
714 ; what ? 717. 

Beings, all natural, form only one 
chain, 713. 

Bodin, his dangerously atheistical 
"Arcana Sublimium," 648. 

Body, denned, 647 ; enquiry after con- 
stitutive quality of, 647, 700 ; infinite 
creatures are in any given, 652, 702; 
coheres with its fellows, 652 ; never 
wholly quiescent, 652, 657, 699, 703 ; 
errors arising from false notions of, 
684 ; Leibnitz's view of, 684 ; differ- 
ence between the views of Leibnitz 
and Descartes concerning, 699 ; what 
the nature whose diffusion consti- 
tutes? 700; a "machine," 701, 702; 
cannot be destroyed nor absolutely 
produced, 702 ; has a degree of prim- 
itive activity, 702; conspectus of 
systems presented as explanations 
of union of, with soul, 709. 

Bodies, all that is in, explicable by 
magnitude, figure, and motion, 634, 
648 ; are something during, nothing 
between, instants of motion, 648; 
particular, arise from conflicting 
motions, 652 ; are all elastic, 668, 687, 
703 ; their action against each other 
the same, if they approach with 
same velocity, 685; no elements of, 
687 ; distance between, never the 
same, 690 ; their phenomena can be 
explained mechanically, 699; can- 
not demonstrate existence of, 719. 

Boeder, 650. 

Burgoldensis, probable author of 
" Itinerarium Politicum," 650 ; com- 
mentator on " Iustrumentum Pacis," 
650. 

Campanella, his "De Sensu Rerum et 

Magia," 646. 
Cartesians, have added little to dis- 



coveries of Descartes, 632 ; Leibnitz 
refuses to be classed among, 634 ; re- 
lations to the ancient philosophers, 
645; "subtile matter" of, 651; on 
communication of motion by im- 
pact, 685, 688, 704; admit no vac- 
uum, 699 ; essence of body, according 
to, 699; acknowledge inertia, 701; 
reject action in bodies and find it in 
God, 703 ; modifications of views on 
force, 704 ; suppose a body in mo- 
tion proceeds per saltum, 704; the 
disciples among, not so careful in 
statements as their master, 705 ; as- 
sume redundantly the "Deus ex 
Machina," 709 ; posit "primary 
elements" instead of veritable 
unities, 712; their reasoning con- 
cerning the existence of the most 
perfect being, 715. 

Cause, The, through which minds 
have intercourse, 720. 

Causes, final, agents in research, 680 ; 
both final and efficient, pertain to, 
and help in physical discussion, 704. 

Centaur, the species of, exists in mind, 
718. 

Change, spontaneous, admitted by 
philosophers in simple being, 711. 

Changes, enumerated, 638 ; reduced to 
forces, 706. 

Cicero politely laughs at Epicurus, 
643; his " De NaturaDeorum," 643. 

Classes of beings, linked together in 
one chain, 713; their limits cannot 
be precisely given, 713. 

Coins, how two of different metals 
may be distinguished, 653. 

Collegium Philadelphicum, 650. 

Colors, arise from motion, 639. 

Column, how extracted from the rough 
block, 638. 

Conatus, 671, 673, 675, 678, 695, 701, 
702, 706. 

Concurrent bodies, same relative ve- 
locity preserved between, 658; 
"total progress" preserved be- 
tween, 658; absolute force con- 
served in, 659, 660; why they can 
stop each other, though unequal in 
"living force," 660; augmentation 
of "living force" in, would lead to 



INDEX B 



825 



perpetual mechanical motion, 661 : 
diminution of "living force" in, 
would lead to destruction of force, 
661 ; conservation of " moving ac- 
tion " in, general rule as to, 661 ; 
conservation of "moving action" 
in, general demonstration of, 663; 
conservation of "moving action" 
in, proved by an example in num- 
bers, 663; conservation of " moving 
action " in, proved by rules of per- 
cussion, 666; lineal equation which 
expresses conservation of cause of 
impact in, 667; plane equation 
which expresses conservation of 
total progress in, 667 ; solid equation 
which expresses conservation of 
total absolute force in, or of "mov- 
ing action" in, 667; the interde- 
pendence of the three equations con- 
cerning, 668 ; are to be regarded as 
"hard-elastic," 668; influence of 
degree of elasticity in, 670 ; both act 
equally in concourse, 688 ; compres- 
sion from impact equal in each of 
them, 689. 

Conditions amid space, 645. 

Congruity of phenomena, 718. 

Connection between all parts of uni- 
verse, 713. 

Conring, Hermann, 636 ; on forms, 638. 

Continua, how defined by Aristotle, 
637; of two kinds, 700; successive, 
700 ; simultaneous, 700. 

Continuity, law of, 668 ; excludes 
change per saltum, 687 ; applied to 
zoology and botany, 713. 

Continuum, 687. 

Corporeal things, more involved in 
their explanation than geometry 
and logic, 679. 

Corpuscle, each, awaits an occasion 
of exercising its power, 705. 

Corpuscular philosophy, its abuse, 672. 

Corruption and its correlative genera- 
tion result from motion, 639. 

Creation, continuous, in motion, 648, 
650, 679; a Divine Mathematics or 
Metaphysical Mechanics in, 694. 

Dance, tight-rope, why pleasing? 697; 
sword-, why pleasing ? 697. 



Death, if we awaken in, what then? 
719. 

Democritus, his atoms freed from con- 
tempt, 671 ; regarded body as inert 
mass, 677; holds a vacuum, 699; 
regarded rarefactions as only ap- 
parent, 699; thought there was 
something passive in body, 699; 
taught that the phenomena of bod- 
ies can be explained mechanically, 
699, 712. 

Descartes, Clauberg clearer than, 632 ; 
disciples of, 633 ; argument of his 
method the only distinctive doctrine 
of, held by Leibnitz, 634; his " Me- 
ditationes," 634; opposes vacuum, 
634, 699 ; contends for plenum, 634 ; 
" subtile matter " of, 651 ; his "uni- 
versal rings," 651; distinguished 
velocity from direction, 675; re- 
garded motion quoad phenomena as 
mere relation, 685; his inaccurate 
statement about concourse of a 
larger and smaller body, 685 ; de- 
nies that all reflection arises from 
elasticity, 687 ; a testing application 
of his co-ordinates to conditions of 
motion in concurrent bodies, 688 ; 
saw only extension in body, 699; 
believed that phenomena of body 
could be explained mechanically, 
699; acknowledged natural inertia, 
701 ; believed force to be a compo- 
site system of mass and velocity, 
704 ; found no reason for assuming 
forms and forces in bodies, 705 ; 
his assumption that the notion 
of a perfect being exists criticised, 
715. 

Deunculi, substantial forms virtually, 
646. 

Deusing, 632. 

Development in perfect order, the law 
of all things, 712. 

Digby, Kenelm, 632; his "Peripatetic 
Institutions," 641. 

Discontinuity, how induced in primary 
matter, 637. 

Dreams, how related to body, 708; 
well-ordered, are equivalent to truth, 
719. 

Duration, defined, 700. 



826 



LEIBNITZ'S CRITIQUE OF LOCKE 



Effect, violent, what? 659, 662. 

Effort, an illustration of, 674 : is two- 
fold, 674. 

Elasticity, whence ? 668 ; everywhere 
present, 669, 687 ; often insufficient, 
669; all reflection comes from, 677, 
687 ; necessary to laws of motion, 
703; necessary to "law of continu- 
ity," 704; necessary to "law of 
equivalence," 705 ; assists in uniting 
" necessity of matter with beauty of 
form," 705; shows the presence of 
internal motion and infinite primi- 
tive force, 705. 

Ellipse passing into parabola used as 
an illustration, 687; may represent 
a circle optice, 717. 

Energy, primitive, 703. 

Entelechies, evreX^xeiat, 671, 672, 679, 
680, 699, 701, 703, 705, 712. 

Entities, the only given, 645. 

Epicurus, 643, 644; bestows per se 
downward motion on his atoms, 643 ; 
laughed at by Cicero, 643; denies 
motion from without, 644; admitted 
progress into infinite, 644. 

Equilibrium, what? 659; relation of 
heights and weights in, 659. 

Essence, or possibility itself, 693, 695 ; 
of matter, 637; of body, 647, 671, 
678, 684, 699, 700. 

Eternity, of world, does not set aside 
an extramundane reason for its 
existence, 693 ; of existence does not 
explain existence, 719, 720. 

Existence, its sufficient reason not in 
a succession of states, 692 ; not in 
things, 692; essence per se tends to, 
693; quantity of, greatest possible 
under conditions, 694 ; in the num- 
ber of the perfections, 715; how 
proved? 717. 

Express, to, what? 716. 

Extension, what? 647, 671, 699, 700; 
how we conceive, 711. 

Feelings of soul, a consequence of that 

which is in it, 707. 
Figure, what? 637, 643, 703; arises 

from motion, 642. 
Flowing, free curvilineity, 640. 
Force, and quantity of motion, not 



the same, 659 ; absolute, to be meas- 
ured by violent effect, 659; dead, 
the equivalent of equilibrium, 659; 
when living, developed, 660; how 
dead, estimated? 660; how living, 
estimated, 660; is twofold, 674; 
dead, or elementary, 674; living, is 
twofold, 675; total living, 675; par- 
tial living, 675 ; partial respective, 
675 ; partial directive, 675 ; total ab- 
solute, how composed, 675 ; — prim- 
itive active, 701 ; is the ivreX^xeia 
J; Trpibrri of Aristotle, 701 ; is form of 
substance, 701 ; how affected by im- 
pact, 703; — derivative, what? 702, 
703; its amount maintained, 702; 
differs from action, 702; — active, 
placed in bodies, 702 ; originally in 
God, 702 ; internal, turns itself with- 
out, 703. 

Forces, how they exist, 704. 

Form, what? 637; substantial, con- 
sists in the indivisible, 640; what, 
according to Scholastics, 643. 

Forms, from active power of Efficient 
One, 632; how they originate, 638; 
substantial, endowed with intelli- 
gence, 646; appetite assigned to, 
646; axioms connected with, 646; 
— how the doctrine of, must not be 
employed, 672. 

Full, all things are, 652. 

Galileo, his expression "the infinite 
force of percussion," 674 ; his inves- 
tigations concerning living force, 
675. 

Gassendi, 632 ; not strictly a Cartesian, 
633; contends for a vacuum, 634, 
699; places body in inert matter, 
677; his remarkable experiments, 
691. 

Generation, how ex2Dlained by motion, 
638. 

Geometry, demonstrates from causes, 
642; Aristotle's view of, 642; is a 
science, 642; defined, 700; its rela- 
tion to arithmetic, 700. 

Glauvill, Joseph, his History of the 
growth of science since Aristotle, 
631. 

God, the primary matter of things, 



INDEX B 



827 



632; forms produced from his ac- 
tive power, 632 ; produces creatures 
from his active power, 632; must 
not be introduced in explanation to 
the exclusion of acting in things, 
679 ; free, yet does all things deter- 
minately, 695; in him not only ex- 
istences but possibilities have reality, 
695 ; progress to be recognized in his 
works, 698 ; how beings exist in the 
ideas of, 712; world in a measure 
represents, 717 ; not a deceiver, 719 ; 
is Cause of intercourse between 
minds, 720 ; is a Cause, but has no 
cause, 720. 

Goezius, publishes the " Collegium 
Philadelphicum," 650. 

Greatest expressed in smallest, 712. 

Gyri, 651. 

Heat, a form of motion, 639. 

Hermetics, 712. 

History, how confirmed, 720. 

Hobbes, 632; not strictly a Cartesian, 
633; asserts possibility of both ple- 
num and vacuum, 634; his vortices, 
651. 

Hooke, his "Micrographia," 639; his 
" Sylvula " of rust, 639. 

Huygens, his "method of a boat," 
666; adorns the age with splendid 
discoveries, 676. 

Hypotheses, rule for choosing among, 
637. 

Hypothesis, the, of modern philosophy, 
637; a defect in, 646. 

Idea, something in mind, 716 ; not im- 
pression on brain, 716 ; not every- 
thing in mind is an, 716; is a power 
in mind, 716; may exist without 
thinking, 716 ; a power near at hand 
of thinking about a thing, 716 ; must 
not. only tend to the thing, but ex- 
press it, 716 ; need not resemble its 
thing, but it presents truths which 
would be confirmed in the thing, 717. 

Ideas for which the age was not pre- 
pared, 714. 

Impetus, what? 673. 

Impulse, made from infinite degrees, 
674. 



Incompatibility, only demonstrated by 
resolution of terms compared, 714. 

Increment, the momentary, in a force 
striving for change is real, 671. 

Indifference of will, arises from igno- 
rance, 695. 

Infinite, should be recognized in every 
thing, 712. 

" Influence, the system of," the Scho- 
lastic method of explaining connec- 
tion of body and soul, 709. 

Intelligences, of Aristotle, 651, 711 ; 
discarded, 680; — used by God not 
as machines but subjects, 698, 702. 

Intercourse, and by consequence ex- 
istence, of minds, its cause in God, 
720. 

" Journal des Savants," 707. 
" Journaux," 699. 
Joy, the law of, 697. 
Justice, the law of, 697. 

Kabbalist, 712. 
Kepler, 701. 

Laws, mechanical, from higher reas- 
ons, 680; of God imply means of 
accomplishment, 709. 

" Leap," no change by, 669, 686. 

Leibnitz, how far a Cartesian, 634; 
his juvenile production, "Hypothe- 
sis Physica," 677 ; his maturer judg- 
ment of "Hypothesis," 695. 

Light from motion, 639. 

Living force, see Force. 

Malebranche, his " Search after Truth," 
657 ; his rules of motion, 688. 

Marci, Marcus, his "De Ideis Opera- 
tricibus," 646. 

Mariotte, on rules of motion, 677; 
points out that a body bends before 
it is propelled, 687. 

Matter, defined, 645; subtile, of Des- 
cartes, 651 ; tends to rest or anni- 
hilation, 652 ; infinitely divided, 652 ; 
more than extension, 700. 

Matter, primary, what? 637, 672; dis- 
continuity in, how effected, 637; 
how all things produced from, 637 ; 
of Aristotle, 651; and space the 



828 



LEIBNITZ'S CRITIQUE OF LOCKE 



same, 652 ; if at rest is nothing, 652 ; 
obscurely hinted at by Scholastics, 
652; if moving in parallel lines is 
nothing, 652. 

Mechanics, ancient, dealt with dead 
force, 675. 

Mechanism, a physical, illustrative of 
metaphysical problems, 695. 

Mercury, the basis of all metals, 640. 

Metals, whence they arise, 640. 

Metaphysical laws prevail over geo- 
metrical, 695. 

Mind, source of motion, 643; liberty 
and spontaneity alone in, 643; de- 
fined, 645. 

Mobile, 673. 

Molyiieux, his " Dioptrics," 680. 

Moral perfection is physical, 696. 

More, Henry, his Archseus, 679. 

Motion, originates in mind, 643; de- 
fined, 645, 673; not given in bodies, 
648 ; a continual creation, 648 ; source 
of all particulars, 651; is circular, 
652; and body, 652; in what case 
not external, 652 ; same quantity of, 
not preserved in concurrent bodies, 
657; quantity of, what? 657, 673; 
never exists, 671 ; term applied to 
instantaneous element of motion, 
673; systematic rules of, 678, 679; 
why real, 685 ; a relation, 685 ; Des- 
cartes' mistakes in relation to, 685; 
proper, separated from common, 689 ; 
as a tendency rectilinear, 689 ; why 
curvilinear, 690; its true nature, 
690, 691 ; when common in many 
bodies, does not change their action 
among themselves, 691. 

Motions, their compositions and resolu- 
tions, 691, 692. 

Motive force, in bodies intrinsically, 
699. 

Natural history, discoveries expected 
in, by employment of Law of Con- 
tinuity, 713. 

Nature, Two Laws of, which Leibnitz 
first made known, 668 ; Aristotle's 
definition of, approved, 699. 

Naudseus, 648. 

Necessity metaphysical, 693 ; physical, 
693 ; hypothetical, 693. 



" Nouvelles de la Republique des Let- 

tres," 687. 
Number denned, 645. 

Order, a general principle of, 687 ; its 
foundation, 687; its enunciation, 
687; its illustration, 687. 

Origin of things, on the radical, 692. 

Paradise, why the world is not yet a, 
698. 

Parts not neglected for sake of total- 
ity, 697. 

Passion of bodies, spontaneous yet 
occasioned, 688; proper, arises from 
percussion, 688. 

Perfection is quantity of essence, 693 ; 
is degree of essence, 695 ; that through 
which greatest number of things are 
compossible, 695; a source of ex- 
istence, 695. 

Peripatetics, their forms referred to 
intelligible notions, 671. 

Phantasmata, how certified that things 
are not, 647. 

Philosophic temperament, the, which 
suits piety and science, 680. 

Philosophies, none of them worthy of 
contempt, 671. 

Philosophy, the Reformed, its com- 
mon rule, 634 ; its reconciliation with 
Aristotle, 636 ; its relations with 
Aristotle, 645. 

Physics, why misunderstood by Schol- 
astics, 636. 

Plato, his Ideas, 671 ; his entelechies, 
699. 

Platonists, 712. 

Plenum, 634. 

Position, defined, 645. 

Possibility, is essence, 693, 695. 

Power, active, is force or form, 701; 
a tendency to action, 701 ; not a 
faculty, 701 ; is primitive or sub- 
stantial, 701 ; is derivative or acci- 
dental, 701. 

Power, passive, is matter, 701; is im- 
penetrability or antitypy, 701; is 
resistance or inertia, 701 ; is every- 
where the same, 701. 

Power in body, twofold, 701. 

Progress, quantity of, what, 658; of 



INDEX B 



829 



universe never 

698. 
Projectiles, 691, 702. 
Putrefaction, 638. 

Quadratices, 711. 

Qualities, changed through motion, 
639; depend on organs, 640; with 
exception of forms reduce to forces, 
706. 

Roeus, on Aristotle, 641. 

Reality, both of essences and exist- 
ences, their ultimate reason, 695. 

Red Cross, Society of, 650. 

Reiser, Anton, 649. 

Repetition, discrete or continuous, 700. 

Rest, evanescent motion, 687 ; " ex- 
cludes leap from change," 687 ; ad- 
vantage of regarding it as a case of 
motion, 687, 688; not cause of sta- 
bility, 690; true, does not exist, 
690. 

Rings in primary matter, 651. 

Rust, 639. 

Salts, their nature, 640 ; the causes of 
fixity, 640. 

Sarmatian salt-pits, 696. 

Scaliger, harmonized Aristotle and 
moderns, 641 ; his dvvafjus wXacrTiKri, 
646. 

Scholastics, their queries concerning 
primary matter, 637 ; their relation 
to mathematics, 642. 

Schurzneisch, 650. 

Sciences, " a certain harmonizing of 
the," 642. 

Snow, what ? 639. 

Solicitation, an infinitely small mo- 
tion, 659, 674. 

Solidity from motion, 651. 

Souls and entelechies, we give no place 
to, 680; why so much conferred on? 
698; concentrate universe in them- 
selves, 698 ; always connected with 
organic bodies, 701. 

Space, defined, 645 ; why real, 684, 685 ; 
no vacant, 690 ; in what sense said 
to be extended, 700. 

Spener, 649. 



Sphericity, tendency of bodies in flu- 
idity to assume, 694. 

Spizel, his "Confessio naturae contra 
Atheistas," 649. 

Stability, true notion of, 689; abso- 
lute, does not exist, 689 ; defined, 
690 ; not derived from rest, 690 ; not 
explained by pressure, 690. 

Stoics, tranquillity of, 671. 

Substance, changed by motion, 639; 
what happens in, happens in an or- 
derly manner, 686 ; apart from soul, 
au aggregate, 701. 

Sufferings of good men result in greater 
good, 698 ; short roads to perfection, 



Theologians and philosophers discuss 
the same questions, 644. 

Thing, a, how distinguished from other 
things, 652. 

Things, corporeal, possess tendency 
or effort, 671; something has been 
placed in them by God, 679 ; are part 
of the Kingdom of Power or of the 
Kingdom of Wisdom, 680 ; existing, 
in what sense necessary, 693; their 
original formation, 693, 694 ; reasons 
of, not found in their series, but in 
metaphysical truth, 695 ; depend not 
on material necessities, but formal 
reasons, 695. 

Thomas Anglus, on immortality of 
soul, 641. 

Thomasius, Jacob, Leibnitz's letter to, 
631. 

Time denned, 645, 711 ; Aristotle's defi- 
nition of, 645 ; never exists, 671 ; real, 
684. 

Trew, Abdias, 641. 

Truths, contingent, originate in meta- 
physical, 693 ; — eternal, exist in a 
metaphysical subject, God, 695 ; reg- 
ulate things, 695; are reasons of 
existence rather than non-existence, 
695 ; are reasons of the so-existing 
rather than the otherwise-existing 
world, 695 ; prevail over geometrical 
laws, 695. 

" Uniformly," how applied to action of 
beings, 710. 



830 



LEIBNITZ'S CRITIQUE OF LOCKE 



"Unities, veritable," to be posited at 
foundation of things rather than 
"primary elements," 712. 

"Unthinking, the," nothing, 652; no 
variety in, 652. 

Vacuum, 634, 635, 638, 699, 708, 712. 

Vaninus, 648. 

Velocity, relative, between concurrent 
bodies, preserved, 658; how esti- 
mated, 662; defined, 673; with di- 
rection called conatus, 673; distin- 
guishable from direction, 675. 

" Vividness," of phenomena, 718. 

Vossius, his criticism on Descartes, 
634. 

Wallis, 677, 692. 
Water, elastic, 703. 

Weights in motion exhibit the greatest 
possible descent of heavy bodies, 694. 
Weigel, 641. 
White, the color, 639. 
Whole never exists, 671. 



Wisdom determines to the most per- 
fect, 695. 

World, the four things necessary to 
explain its phenomena, 646 ; in 
it is realized the greatest produc- 
tion of possibilities, 694 ; physically, 
not metaphysically, necessary, 694 ; 
— this, not the best, apparently 
shown by exj>erience, 696; a priori 
argument against, 696 ; a supposi- 
tion founded on partial knowledge, 
696 ; the most perfect possible, 
696; the most perfect physically, 
696 ; the most perfect morally, 696 ; 
an admirable mechanism and the 
best Republic of Souls, 696 ; its evils 
but as purposed discords in a musi- 
cal composition, 697 ; represents God, 
717. 

Wren, 677. 

Zeno, Leibnitz claims accord with, 711. 
Zoophytes, not monstrous, but orderly 
productions, 713. 



INDEX C 

TO THE NOTES, ADDITIONS, AND CORRECTIONS 



A posteriori knowledge, Leibnitz's 
view of, 109, 227, 758 ; Kant's view 
of, 109, 227, 758. 

A priori knowledge, Leibnitz's view 
of, 109, 227, 758 ; Kant's view of, 109, 
227, 758. 

Ab universali ad particulare , is it ap- 
plicable always? 569; the principle, 
De continente et contento, 569. 

Abel, Niels Henrik, demonstrates the 
impossibility of reducing by radi- 
cals general equations higher than 
the fourth degree, 571. 

Absinthium, 765. 

Absolute, belongs to reason, 158 ; how 
we become acquainted with it, 158. 

Abstraction, to what extent a depart- 
ure from reality, 728. 

Academic, des Inscriptions et Belles- 
Lettres, 547 ; Francaise, 550 ; des 
Sciences de Paris, 550. 

Academy, Old, 518. 

Accidentia, 455. 

" Accidents and abstracts," their con- 
sideration develops the differences 
between the theories of Locke and 
Leibnitz, 749. 

" Acroamatic," the epithet explained, 
42, 272, 724. 

" Acta Concil. Reg.," 581. 

"Acta Eruditorum," 6, 14, 101, 174, 
227, 425, 434, 484, 502, 511, 670. 

Acts 17 : 28, 153. 

Adam as a symbol in Boehme's philos- 
ophy, 298. 

Adams, F., "The Genuine Works of 
Hippocrates," 476. 

Adamson, on Gassendi, 421. 



Adelung, J. C, " Gesch. d. mensch, 
Narrheit," 600, 601, 604, 605. 

Aerial vehicles of spirits, 380. 

jEschylus, " Prometheus Vinctus," 389. 

Agnosticism, 195. 

Agreement or disagreement, Leibnitz 
reduces Locke's enumeration of the 
kinds of, 401. 

Aimant, 1', Leibnitz writes upon, 740. 

Air, scholastic conception of, 740. 

Aix, its derivation, 301. 

Albertus Magnus, 278, 381; unjustly 
suspected of magical practices, 278. 

Albinus Flaccus, instructor of Charle- 
magne, 546; " Opera," 546. 

Alcuin, see Albinus Flaccus. 

Aldrich, Henry, " Artis Logicse Rudi- 
menta," 456, 766, 769. 

Alexander of Aphrodisias, 581. 

Alexander the Great, 536. 

Alexandrists, 581. 

Allbeseeltheit, 732. 

Alliot, Jean Baptiste, his "Traite du 
cancer," 352; — Pierre, his "Theses 
medicse de motu sanguinis circu- 
lato," 352 ; his " Epistola de cancro 
apparente," 352; his " Nuntius pro- 
fligati sine ferro et igne carcino- 
matis," 352. 

Allnian, G. J., " Greek Geometry from 
Thales to Euclid," 108, 463, 475, 527 ; 
" Pythagorean Geometry," 475. 

Alsted, J. H., 311, 398 ; his " Encyclo- 
paedia," 311, 363 ; and " Systema 
logica? harmonicum," 398. 

Amadis de Gaula, 399. 

Amare (diligere) denned, 750. 

Amor non mercenarius, 750. 



831 



83 



LEIBNITZ'S CRITIQUE OE LOCKE 



" Anabaptisticum et enthusiasticum 
Pantheon," 601. 

Anabaptists, 602. 

Analogy, the class of phenomena in 
which it affords probable conclu- 
sions, 549; its conclusions are only 
rational hypotheses since not founded 
on complete inductions or mathe- 
matical data, 550 ; the rationality of 
a conclusion drawn from, on what 
it depends, 550. 

Analysis, how explained by Pappus, 
521. 

Anaxagoras, 65, 519. 

Anaximenes, 519. 

Andrada, Diego Payva d', theologian, 
592 ; on salvability of heathen, 592 ; 
his " Orthodoxarum explicationum 
de religionis Christians capitibus 
libri X.," 592; his "Defensio Tri- 
dentinae fidei," etc., 592; maintains 
a controversy with Chemnitz, 592. 

Andrews, E. B., " Institutes of General 
History," 453; on quartus modus, 
455. 

Andrise, Tobias, 633. 

'Ai^/cSora, Ta, of Procopius, 542. 

Anima mundi, 382. 

Animalcula within animalcula, 722. 

" Animant," its meaning, 125 ; its per- 
haps preferable variant, 125, 740. 

Anselm, founder of Christian Scholas- 
ticism, 502; his " Mouologium," 502 ; 
his " Cur Deus Homo," 502, 503; his 
" Proslogium," 502, 503 ; his " Liber 
apologeticus," 503; his ontological 
argument for existence of God, 503 ; 
several of his tractates which have 
been translated, 503. 

Antimony, 324. 

Autipodes, 444. 

Anti-Ramists, 408. 

Antisthenes, 518; taught that virtue 
only is good, 518 ; a list of his writ- 
ings, 519. 

Antitypy, avTirvwia, 721, 722. 

Antoninus, Marcus Aurelius, 495 ; his 
" Meditations," or " Thoughts," 495. 

Apagogical demonstration, 491. 

Apes have organs of speech, 286. 

Apodeictic syllogism, 565. 

'A7r65ei.£ts, 564. 



Apollonius of Perga, 108 ; his "Treatise 
on Conies," 108, 465. 

Apostolici Regiminis, the papal decree 
of, 581. 

Appuleius, 455. 

Apuleius, 243 ; his " Metamorphoses " 
summarized, 243. 

Aquaviva, Claudius, 619; his "Ratio 
Studiorum," 619. 

Aquinas, Thomas, 230, 503; his 
"Summa Theologiaj, 230, 496, 503, 
729 ; on species, 381 ; a realist, 382 ; 
criticises ontological argument for 
existence of God, 503; his "Contra 
Gentiles," 503 ; censured by Spinoza, 
504; on "ignis infernus," 730; op- 
posed by Lessius, 749; his use of 
"phantasm," 769. 

Arbor Porphyriana, 322 ; prmdlca- 
mentalis, 322 ; prsedicabilis, 322. 

Archseus, 67, 382, 733. 

Archilaus, a physicist, 519. 

Archimedes, 93, 108; gi-eatest Greek 
mathematician, 414 ; the first mathe- 
matical engineer, 414; best edition 
of his works, 414. 

Argenteus, Codex, 295. 

Argot, 293. 

"Argument," as applied to middle 
term, 4S1. 

Argument, topical, 564. 

Argumentum, simplex, 398 ; com- 
plexum, 398. 

Ariosto, his " Orlando Furioso," 399. 

Aristippus, 518; made pleasure end of 
life, 518 ; his definition of pleasure, 
518; his writings enumerated, 518; 
his philosophy discussed, 518. 

Aristotle, 66; his " Nicomachean 
Ethics," 96, 180, 285, 321, 752, 753; 
his "Physics" (<$>v<tikt] 'Aicpdacris), 
156, 157, 174, 272, 320, 321, 750, 751 ; 
his " Metaphysica," 156, 174, 311, 
320, 495, 498, 751; his definition of 
probability, 214; his "Rhetoric," 
214; his "AnalyticaPriora,"214,636; 
his "Meteorologica," 277; on Milky 
Way, 277 ; his " De Anima," 281, 321, 
724, 760, 763 ; his " De Interpreta- 
tione," 281, 291, 452, 763 ; on man as 
a social being, 285; his "Politeia," 
285, 286, 482; his "Categories," 



INDEX C 



833 



311; on genus and difference, 312; 
Leibnitz's defence of, from Locke's 
strictures, 312: his "Topica," 312, 
418, 564, 565, 636; on motion, 320, 
321 ; on light, 321 ; ov<rla, how used 
by, 349 ; his vovs Trader ikos, 381 ; his 
vovs itolt]tlkos, 381 ; on knowledge 
as dependent on things previously- 
known, 413; his "Analytica Posteri- 
ora," 413, 636 ; Leibnitz's opinion of, 
416; on evdo^a, 418; his use of i'diov, 
455 ; his limit to scientific considera- 
tion, 488; his Ka 66\ov irpQrov, 488; 
his irepl ^,o<Phttikwi> 'EXeyx^v, 519 ; 
i n a pupil's prior and provisional 
faith in his teacher, 519; his defini- 
tion of " topical argument," 564; is 
" unsaved," 593 ; on mind as an 
unwritten tablet, 726; his "Magna 
Moralia," 752, 753; his " Eudemean 
Ethics," 753; on will and freedom, 
753 ; on soul as not indifferent to 
every kind of matter, 760 ; on mid- 
dle term, 770. 

Arminians, the later, 733. 

Arminius, James, 72. 

Arnauld, Antoine, 463, 530; Leibnitz's 
letter to, 101 ; on Descartes' funda- 
mental dictum, 410; "GEuvres," 
463 ; " La Logique ou L'Art Penser," 
464; his controversy with Holden, 
617 ; — Simon, Marquis de Pomponne, 
605. 

Arnold, Gottfried, " Kirchen und 
Ketzerhistorie," 600, 602. 

Arrian, reporter of Epictetus' talk, 
496. 

Art schools, Leibnitz favors their 
founding, 628. 

Artes liberates, 628. 

Askath Eochel, 242. 

Assassins, the, 197. 

Association, Law of, its germ in Leib- 
nitz's teaching, 764. 

" Assurance Magazine," 540. 

Atomism, Leibnitz early defends, 723. 

Atoms, an additional argument against, 
656 ; non-existent, 722 ; why rejected 
by Leibnitz, 727. 

Aubery, see Maurier. 

Augustinus, Aurelius, anticipated Des- 
fundamental dictum, 410 ; 



his " Soliloquium," 410, 516; ground 
of his philosophy, 516 ; his "De 
Beata Vita," 516; "De Trinitate," 
516,589; "De Vera Religione," 516; 
literature illustrative of philosophy 
of, 516 ; " De Ideis," 516, 594 ; on con- 
sciousness involving in itself the 
idea of God, 575 ; "De peccatorum 
meritis et remissione et de Bap- 
tismo parvulorum," 594; "De pec- 
cato originali," 594 ; " Encheiridion 
ad Laurent.," 594 ; " De nuptiis et 
concupiscentia," 594; "Contra Juli- 
anum Pelagianum," 594 ; "Contra 
duas epistolas Pelagii," 594; teaches 
that babes dying unbaptized are in 
some sort damned, 594; his "De 
Civitate Dei," 594, 729 ; his "Opera," 
616 ; on a future material fire, 729. 

Augustus I., alchemist, 339. 

Authority, Leibnitz opposes blind sub- 
mission to, 579. 

Aventinus, Johann Thurmayr, his 
" Annales Boiorum," 546. 

Averroes, 581. 

Averroists, 581, 590, 732 ; related to 
Mystics and Quietists, 728. 

Axioms, their demonstration, 463; 
should they be lessened ? 770. 



Baader, von, his relation to Boehme, 
298. 

Bachet de Merzeriac, his edition of 
" Diophantus," 571. 

Bacon, Francis, 591 ; on Idola Fori, 
306; his "Novum Organum," 306; 
his "DeAugmentis,"306; Leibnitz's 
estimate of, 306; editions of his 
works, 306, 307; Spinoza's refer- 
ence to, 526; his " Spiritus," 684; 
- Roger, 278. 

Bagheminus, 632. 

Baitar, Ibn al, 371; greatest of Ara- 
bian botanists, 371 ; his alphabetical 
list of simples, 371; his "Materia 
Medica," 371; sources of informa- 
tion concerning, 371. 

Balaam, Leibnitz's essay on, 767. 

Bancroft, "History of United States 
of America," 599, 773. 

Barantola, 737. 

Barbeyrac, Jean, 286; translator of 



LEIBNITZ'S CRITIQUE OF LOCKE 



the "De Jure" of Grotius, 286; 
translator of Pufendorf, 436. 

Barclay, Robert, 599 ; his "Apology for 
the True Christian Divinity," 599. 

Bardeen, C. W., editor of Comenius, 
466. 

Barner, Jacob, 487 ; his " Prodrornus 
Sennerti novi," 487. 

Basilius, Valentinus, his " Schluss-Re- 
den," 324; his "Chymische Schrif- 
ten," 324. 

Basnage de Beauval, his " Histoire 
des Ouvrages des Savants," 50, 
507; his "Histoire critique de la 
Republique des Lettres," 50B. 

Baudoin, Jean, his " L'homme dans 
la Lune," 342. 

Bauhin, Jean, a founder of modern 
botany, his "De Plantis Absinthii 
nomen habentibus," 308; his " His- 
toria universalis Plantarum," 309; 
— Gaspard, 308. 

Baumgarten, H., " Ueber Sleidanus 
Leben und Briefwechsel," 114. 

Baumgarten, Martin, his " Travels 
through Egypt, Arabia, and Pales- 
tine," 89, 735. 

Bayle, Pierre, 507, 727 ; his " Nouvelles 
de la Republique des Lettres," 50 ; 
his " Dictionnaire historique et cri- 
tique," 278, 444, 507, 531, 601, 604, 727 ; 
his "Dictionary" article " Rora- 
rius," 66,507, 508. 

Baynes, Thomas Spencer, translates 
the "La Logique ou L'Art de Pen- 
ser," or the Port Royal Logic, 14, 464. 

Bears, child of the, 344. 

Becan, John (Van Gorp), 303; his 
" Origiues Antwerpianse," 303; on 
the original language, 303; on the 
site of Paradise, 303. 

Bede, the Venerable, his "Ecclesias- 
tical History," 295. 

Begriff, 330. 

Begriffliche Wesen, 311. 

Beings, notional or conceptional, 311. 

Bellarmin, his "De Purgatorio," 730. 

Bellay, Cardinal du, 114. 

Benn, Alfred William, his " Greek 
Philosophers," 108, 156, 421, 576, 724. 

Bergerac, Cyrano de, 228, 399; his 
"Histoire comique des e'tats et em- 



pires du soleil," 228, and also " de la 
lune," 228. 

Berkeley, 772 ; his " Essay towards a 
new Theory of Vision," 747. 

Berkum, H. van, his " De Labadie et 
de Labadisten," 602. 

Bernays, his "Die Dialoge des Aris- 
toteles," 272; " Der Chronik des 
Sulpicius Severus," 345. 

Bernhardt, E., his " Vulfila oder die 
gotische Bibel," 296. 

Bernier, Francois, " Abrege de la Phi- 
losophic de Gassendi," 64, 730. 

Bernouilli, James, 213. 

Beverwyck, Jan van, physician, 624; 
simplifies prescriptions, 624 ; his 
" Idea medicinse veterum," 624. 

Beyerlinck, Laurent, his "Theatrum 
vita? hunianaj," 622. 

Bibliotheca, Maxima Veterum Patrum, 
444 ; Sacra, 503. 

Bibliotheque Universelle, see Leclerc. 

Biel, 382. 

Bigg, his "Christian Platonists of 
Alexandria," 729. 

Blackie, John Stuart, his " Four 
Phases of Morals," 598. 

Blackburue, Francis, his "Historical 
View of Controversy concerning an 
Intermediate State," 775. 

Blasius, Gerard, 351. 

Bochart, Samuel, 302; on the connec- 
tion of languages, 302. 

Bodin, Jean, the earliest systematizer 
of Political Economy, 648. 

Boeder, Johann Heinrich, 650. 

Body, in Cartesian sense, 348 ; invisi- 
ble, why believed in, 721 ; what? 
721,722; mere phenomena, 756; its 
action phenomenal, 756. 

Boehme, Jacob, 298, 732 ; a Protestant 
theosophist, 298 ; the first charac- 
teristically German philosopher, 298 ; 
forerunner of Leibnitz's metaphysic, 
298; his "Das dreyfache Leben," 
298 ; his " Sammtliche Werke," 298 ; 
Leibnitz's estimate of, 298, 765; in- 
fluences Quirin Kuhlmann, 601. 

Boethius, 455, 724. 

Bohl, Samuel, his researches into the 
Massoretic system of Hebrew mark- 
ings, 366. 



INDEX C 



835 



Boiardo, Matteo Maria, Count of 
Scandiano, his " Orlando Innamo- 
rato," 398. 

Boileau-Despreaux, Nicolas, his " Sat- 
ires," 97, 736. 

Bolsec, Jerome Hermes, advocates 
Pelagian views in Geneva, 545 ; cen- 
sured by Calvin, 545 ; imprisoned by 
Senate, 515 ; pursued by Calvin's 
hostility to Bern, 545 ; conceives 
hatred to his persecutors, 545 ; writes 
his "Histoire de la Vie, Mceurs, 
Actes, Doctrines et Mort de Jean 
Calvin," 545, ibid, new ed., 773; and 
his " Histoire de la Vie, Mceurs, Doc- 
trines et Deportement de Theodore 
de Beze," 545. 

Boniface, apostle to the Germans, 443 ; 
his "Opera quae extant," 443; his 
controversy with Virgil, 444; Pope 
Zachary's letter to, 444. 

Bonino, G. G., "Biografia medica 
piemontese," 521. 

Bonitz,his " Index Aristotelicus," 383. 

Bonosus, described by Vopiscus, 761. 

Borelli, Giovanni Alfonso, 676. 

Borgia, Francisco, 754. 

Boscovich, 772. 

Bosses, Des, Leibnitz's correspondence 
with, in which is contained clearest 
exposition of the Monadology, 101. 

Bossuet, Jacques Benigne, his corre- 
spondence with Leibnitz, 531. 

Bouhours, Dominique, his " Maniere 
de bien penser dans les ouvrages 
d'esprit," 144; Leibnitz's estimate 
of, 748. 

Bouillier, his "Histoire de la Philo- 
sophic Cartesienne," 421; his 
"Eloges de Fontenelle," 550. 

Boulliau, Ismael, his " Ad astronomos 
monita duo," 573; his "De lineis 
spiralibus," 573; his theory concern- 
ing variable stars, 573. 

Bouquet, his " Rerum Gall, et Franc, 
scriptores," 99; his " Rec. Hist. 
Gaules," 737. 

Bourignon, Antoinette, 599, 728; her 
"Traite' de l'aveuglement des 
hommes," 599; her " La lumiere du 
monde," 599; her "De la lumiere 
nee en tenebres," 599; Kuhlmann 



relations with, 601 ; Labadie's rela- 
tions with, 602; Lacoste's revulsion 
of feeling towards, 604; Leibnitz re- 
fers to, 728. 

Boutan (Bhutan), 736. 

Bowne, Borden P., his " Metaphysics," 
470. 

Boyle, Robert, 324; discovers law of 
compressibility of gases, 324; a 
founder of the Royal Society, 
England, 324; his "Of Absolute 
Rest in Bodies," 324; his works, 
324, 726. 

Brachet, his " Historical Grammar of 
the French," 294. 

Bradley, F. H., his "Principles of 
Logic," 214, 764. 

Brambach, W., his " G. W. Leibniz, 
Verfasser der Histoire de Bileam," 
767. 

Braunfels, his "Kritischer Versuch 
fiber Amaclis," 399. 

Brautigam, L., his "Leibniz und 
Herbart iiber die Freiheit d. menschl. 
Willens," 752. 

Bre'mont d'Ars corrects a mistake of 
Moreri's, 539. 

Britannica, Encyclopaedia, 67, 68, 244, 
294, 311, 399, 421, 425, 475, 542, 552, 
573, 598. 

Brocardica, 486. 

Brooke, Stopford A., his "History of 
Early English Literature," 295. 

Brucker, "Historia Philos.," 278, 606. 

Bruno, Giordano, his use of term 
"monad," 101; his "Delia Causa," 
732. 

Bryce, James, his article " Procopius," 
in "Encyclop. Britannica," 542. 

Bucer, Martin, 114. 

Buddeus, Johann Franz, 713. 

Bulletin des Sciences Mathematiques, 
768. 

Buratini, his flying machine, 749. 

Burckhard, his "Historia Bibliothecas 
Augusts," 242. 

" Burgoldensis," an anagram, 650. 

Buridan, John, his " Questiones Ethi- 
corum Aristotelis," 116 ; his view of 
liberty, 116 : the illustration of the 
fatally indifferent ass not of his 
authorship, 116. 



LEIBNITZ'S CEITIQUE OF LOCKE 



Burnet, Thomas, his correspondence 
with Leibnitz, 6, 478. 

Burridge of Dublin, the Latin trans- 
lator of the " Nouveaux Essais," 37. 

Butler, Nicholas Murray, his "Great 
Educators," 619. 

Cffidmon, his Anglo-Saxon Paraphrase 

of Scripture, 295. 
Caird, E., his article " Cartesianism," 

in "Encyclop. Britannica," 421; his 

" Philosophy of Kant," 319, 332, 503 ; 

his "Critical Philosophy of Kant," 

503. 
Caird, John, his "Introduction to the 

Philosophy of Religion," 274. 
Calculus of Infinitesimals, controversy 

regarding its discoverer, 573; of 

Probabilities, 213. 
Calendar, Gregorian, 424. 
Calixtus, George, 587. 
Campanella, Tommaso, 67, 646, 732. 
Camper, Peter, his " Natuurkuudige 

Verhandelingen," 286; on the lan- 
guage of apes, 286. 
Capella, Marcianus, 455. 
Capes, his " Stoicism," 496. 
Cardano, Girolamo, 67, 106, 566, 572; 

his "De Subtilitate," 106; on the 

spiritusfamiliaris, 730. 
Carlowitz, peace of, 259. 
Carrington, his "History of the Life 

and Death of Oliver Cromwell," 543. 
Casati and Christiana of Sweden, 751. 
Casaubon, Isaac, 478. 
Casimir, John, 344. 
Casuistry to be supplanted by logic of 

probabilities, 213. 
Categories of Kant, arise from Leib- 
nitz's doctrine, 741. 
Cats, Jacob, Dutch poet, 624. 
Cause, primal, its signification, 757 ; 

Hume upon, 757. 
Causes, efficient, depend upon final, 

721. 
Cebes of Thebes, 436; his reputed 

Hival; " spurious," 436. 
Century Dictionary, 67. 
" Certain author, a," 738. 
Certainty, its kinds, metaphysical, 

462 ; moral or physical, 462. 
Cervantes, "Don Quixote," 321. 



Ceulen, Ludolph van, his " Van de 
Circkel," 734 ; his " De arithmetische 
en geometrischefondamenten," 734; 
his " Zetemata," 734 ; computes ratio 
of diameter of circle to its circum- 
ference to thirty-five places of deci- 
mals, 734. 

Chabree of Geneva, his " Sciagraphia," 
309. 

Changeling, 447 ; " Chaungelings,"770. 

"Characteristic, a General," 292, 375, 
437. 

Chastel, P. L., edits Bolsec's Vie de 
Calvin, 773. 

Chauvin, Stephen, his " Lexicon Philo- 
sophicum," 363. 

Chemnitz, Martin, greatest of imme- 
diately post-Lutheran theologians, 
592 ; his " Examen Concilii Triden- 
tini," 592; his "Loci Theologici," 
592. 

Cherler, collaborator with the Bauhins, 
309. 

Cher uel, his " Dictionnaire des Insti- 
tutions Francaises," 757. 

" Chevauchier," 757. 

" Chimerisme," Leibnitz defines, 762. 

Chinese, their dictionaries, 394. 

Xwpur/j.6s, the Aristotelian, 756. 

Christianity consists in its ethical con- 
tent, 607. 

Chrocus, the Vandal, 99. 

Chronicles, II., 6: 18, 158. 

Chrysostom, John, on Greek culture, 
591 ; his hopeful views of humanity, 
591. 

Cicero, his " De officiis," 192, 261, 765 ; 
"De Finibus," 192, 272, 765; "De 
Oratore," 214, 765; "Qusestiones 
Tusculanse," 264; "Ad Atticum," 
327 ; " De Legibus," 500 ; " Topica," 
766. 

Circle-quadrature, historical sketch of, 
425 ; Leibnitz's relation to the prob- 
lem of, 425. 

Cisner, Nicolas, 546. 

Clarke, John, his translation of 
"Jacobi Rohaulti Physica," 233; 
— Samuel, his notes on "Rohaulti 
Physica," 233. 

Class, G., his " Der Leibnizsche Deter- 
minismus," 752. 



INDEX C 



Clauberg, Jean, 303, 304; Leibnitz's 
opinion of, 304; his " De Conjunc- 
tions animae et corporis kumani 
scriptum," 303 ; his " Ontosophia, de 
cognitione Dei et nostri," 303. 

Clavius, Christopher, the Euclid of 
the sixteenth century, 424; assists 
in correcting the calendar, 424 ; his 
"Euclidis elementa," 424; his 
"Sinus lineae tangentis," 424; his 
"Romani Calendarii explicatio," 
424 ; edits " Photismi " of Maurolico, 
442. 

"Clelie, Histoire Roraaine," 223. 

Clement of Alexandria, 575 ; his " Stro- 
mata," 591; on "light of nature," 
591 ; on purgatorial fire, 729. 

Clerc, Jean le, his " Bibliotheque uni- 
versale et historique," 723; his " Bi- 
bliotheque choisie," 723 ; his " Biblio- 
theque ancienne et moderne," 723; 
his abstract of Locke's essay, 728. 

Clericus, J., 733. 

Clerke, Gilbert, 634. 

Clerselier, Claude, his " Les Lettresde 
Descartes," 033. 

Clichtoveus, " Elucidatorium Eccle- 
siasticum," 603. 

Cloelia, the Roman maiden, 223. 

Co-divisions, 337. 

Cock, made into Platonic man, 385. 

Codex Justinian, see Corpus Juris; 
— Argenteus, 295. 

Collateral distributions, 337. 

Collectio Librorum Juris Antejusti- 
niani, edited by Krueger, Mommsen, 
and Studemund, 766, 769, 771, 773. 

Collio, Francesco, 593; his views on 
salvability of pagans, 593 ; held Aris- 
totle " unsaved," 593 ; his " De ani- 
mabus paganorum," 593. 

Comenius, John Amos, a writer on 
pedagogy, 466; his "Opera didac- 
tica," 466; publishes his "Physicse 
ad lumen Divinum ref ormatse synop- 
sis," 466; estimates and biographies 
of, 466. 

Compressibility explained by Leibnitz, 
723. 

" Comptes Rendus," 425. 

Conarion, why the suggested seat of 
soul? 758. 



Concepts, the hypostatizing of, a large 
source of error, 306. 

Conceptio, conceptus, 330. 

"Conclusion, that the, cannot contain 
more than the premises," variously 
expressed, 515. 

Connaway (Conway) , Countess of, 732 ; 
her "Opuseula philosophica," 732. 

Connotations, intrinsic, 738. 

Conring, Hermann, -his vast erudition, 
520; his "Opera omnia," 520; his 
voluminous correspondence with 
Leibnitz, 520 ; taught Oldenbur- 
gerus, 650. 

Consciousness, E. G. Robinson on, 741. 

" Consequent, greatness of the," Janet 
explains the phrase, 756. 

" Contemporary Review," 542. 

Continens et contention, 569. 

Continuity, Law of, 334, 509, 712. 

Contradictory ideas, their combina- 
tion under one notion how detected, 
354. 

Copernicus, Nicolas, 419 ; his " De 
orbium coelestium revolutionibus," 
419. 

Corban, 12~V T , 327. 

Corinthians', L, 2: 9, 200, 583. 

Corneille, Thomas, 536. 

" Corpus Juris Civilis," Mommsen and 
Paris editions, 241, 329, 434, 486, 487, 
492, 497, 534, 735, 759, 766, 769, 770, 
771, 773. 

Corruptio optimi pessima , 482. 

Coste, Pierre, 169; " Essai philoso- 
phique concernant l'Entendement 
humain — par M. Locke," xiv, 4, 
7; as translator of Locke, 101, 727; 
is sometimes clearer than Locke, 
103. 

Cousin, his " GEuvres de Descartes," 
731, 748, 749, 758, 759, 770, 773, 774. 

Creation, Leibnitz's view of, 224 ; 
Locke's view of, 771. 

"Credibility, motives of," defined by 
Leibnitz, 774. 

Cremer, his ' ' Biblico-Theological Lexi- 
con of New Testament Greek," 
289. 

Cromwell, 543. 

Crown, laurel, in surgery, 520. 

"Crusca, La," 18. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Cudworth, Ralph, 05; his "True In- 
tellectual System of the Universe," 
65, 730 ; editions of his works, 65. 

Cynic School, 518. 

Cyrenaic School, 518. 

Dahn, F., his " Prokopius von Case- 
rea," 542. 

Daial-Kirhal, 197. 

Dais, 197. 

Dalgarno, George, 292; his "Ars Sig- 
norum," 292; inventor of manual 
alphabet, 292. 

Damnatio levissima omnium, the fate 
of infants dying unbaptized, 594. 

Dangicourt, a correspondent of Leib- 
nitz, 101. 

Darapti may become Darii, 568. 

Darwin, C, his "Origin of Species," 
345. 

Dasypodius, Conrad, 404; his "Ana- 
lysis Geometries," 404. 

D'Aumont, Louis Marie-Victor, numis- 
matist, 547. 

Debidour, M., his " Thesis " in defence 
of Empress Theodora, 542. 

Decahedron, a nominal definition, 317. 

Definition, according to Aristotle, 312 ; 
Leibnitz's vindication of Aristotle's 
rule concerning, 312 ; on the use of 
loose, 313; Leibnitz's definition of 
nominal, 317, 398 ; of real, 317 ; of ge- 
netic, 317; of causal, 317; Leibnitz 
defines analytically, 318. 

Delecluse,590. 

Delbriiek, B., his " Einleitung in das 
Sprachstudium," 292. 

Delphin classics, 605. 

Democritus, 64 ; on Milky Way, 277. 

Demoivre, his "Doctrine of chances, 
or method of calculating the proba- 
bilities of events at play," 213. 

"Demons or goblins," 730. 

Demonstration, philosophical, reduced 
to syllogism and prosyllogism, 404; 
none according to Leibnitz in Aris- 
totle and Plato, 416; proposal to ex- 
tend its bounds, 437 ; direct, 491 ; 
what it appeals to, 766. 

Denores, Jason, 636. 

Desargues, Gaspard, geometer and 
engineer, 137. 



Descartes, Rene', 64, 348; friend of 
Digby, 83 ; denies vacuum, 127 ; his 
"Principia Philosophise," 127, 128, 
148, 230, 483, 484, 502, 552, 602, 613, 
727. 734, 741, 748, 749 ; his letter to 
Samuel Clarke, 127; hisletter to Mer- 
senne, 137,759; his " Meditatioues 

. de Prima Philosophia," 229, 502, 731 ; 
his " Dioptrica," 230 ; his " Passiones 
Animse," 230 ; his theory concerning 
the Pineal Gland, 230, 758; friend 
of Froidmont, 234; his "Epistles," 
348 ; his remarks on the programme 
of Regius, 348; explodes "inten- 
tional species," 382; his opinion of 
Fre'nicle, 393 ; his preliminary dictum 
anticipated, 410; corresponds with 
Hardy and Fermat, 466; on the 
argument for the existence of God, 
502; " Discours sur la methode pour 
bien conduire sa raison, etc.," 502, 
534; his theory of vortices, 552, 613 ; 
his theory of matter of the first and 
second elements, 613; avoids his 
" rock of velocity," 659 ; Reponses to 
" Objectiones quintse" of Gassendi, 
731; his "Regulse ad directionem 
ingenii," 734; his Platonic Aris- 
totelian dualism, 757 ; letter to 
Meissonier, 758. 

Deschales, Claude Francois Milliet,676. 

Deusing, Anton, his "De vero system- 
ate mundi," 632. 

De Vise', 438. 

Dewey, John, his "Leibniz's New 
Essays, a Critical Exposition," xv., 
17, 128, 129, 131, 317, 319, 336, 363. 

Dialectic syllogism, 564. 

Dieckhoff, his "Leibniz Stellung zur 
Offenbarung," 770. 

Dietz, his " Analecta Medica," 371. 

Diez, Friedrich Christian, founder of 
Romance philology, 294; his " Altro- 
manische Sprachdenkmaler," 294. 

Difference, actual, in what it consists, 
761. 

Digby, Sir Kenelm, his "Treatise on 
the Nature of Bodies, 83; " Demon- 
stratio immortalitatis aninise ratio- 
nalis," 735; on " vacuum," 774. 

Digesta, see Corpus Juris Givilis. 

Dillmann, Edward, his "Eine neue 



INDEX C 



Darstellung der Leibnizischen Mon- 
adlehre auf Grund der Quellen," 102, 
180, 225, 349. 

Diogenes of Apollonia, 519. 

Diogenes the Cynic, and " the man of 
Plato," 385. 

Diogenes Laertius, his "Lives of the 
Philosophers," 379, 385, 518, 519. 

Diophantns, 571 ; his "Arithmeticorum 
libri sex," 571. 

Dioscorides, 371. 

Direct demonstration, 491. 

Disamis, how it may be derived from 
Barbara, 407. 

'Distinguished sufficiently," 727. 

Divini, Eustachio, 613; his alleged 
controversy with Huygens, in " Sys- 
tema Saturnium," 613, 614. 

Doctor juris utriu&que, 758. 

Dods, M., translator of Augustine, 516, 
729. 

Dominis, M. Ant. de, 442; his " De 
Republica ecclesiastica," 443; his 
"De radiis visus et lucis in vitris 
perspectivis et iride," 443. 

' Don Juan ou le Festin de Pierre " of 
Moliere, 536. 

Don Quixote, 321, 766. 

'Donation," the so-called, "of Con- 
stantine," exposed by Valla, 415. 

Dorner, I. A., his " System der Christ- 
lichen Glaubenslehre," 249, 503. 

' Double truth," the doctrine of, 581. 

Drabitius, Nicolas, an enthusiast, 604 ; 
stirs George of Transylvania to an 
unsuccessful movement against Po- 
land, 605 ; burned at the stake, 605. 

Draud, George, 626; his " Bibliotheca 
Classica," 626. 

Dreier, Christian (Peter), 635. 

Drobisch, Moritz Wilhelm, 337; on 
"collateral distributions," 337. 

Du Hamel, Jean Baptiste, 634. 

Duchesne, Andrew, 546; his "Hist. 
Franc. Script.," 737. 

Duncan, G. W., his translation, "The 
Philosophical Works of Leibnitz," 
xiii, 3, 14, 15, 18, 68, 101, 127, 128, 
131, 136, 154, 167, 174, 239, 317, 332, 
346, 363, 381, 383, 420, 421, 470, 502, 
504, 511, 553, 722, 723, 737, 748, 749, 
750, 751, 775. 



Duns Scotus, see Scotus. 

Dupin, Louis Ellies ; his " Bibliotheque 
Universelle des Auteurs ecclesias- 
tiques," 418, 593, 617. 

Durandus, 382. 

Durrius, Johann Conrad, 636. 

Dutens, his " Leibnitii Opera Omnia," 
101, 290, 292, 294, 295, 298, 302, 304, 
306, 311, 317, 318, 324, 333, 337, 344, 
345, 346, 381, 382, 383, 394, 415, 417, 
420, 425, 434, 435, 436, 438, 443, 450, 
451, 465, 466, 478, 484, 486, 495, 496, 
502, 504, 508, 511, 520, 532, 539, 544, 
546, 550, 551, 552, 553, 554, 561, 573, 
579, 590, 591, 592, 595, 600, 606, 626, 
631, 638, 649, 683, 700, 733, 737, 748, 
750, 761, 766, 767, 768, 774. 

Dynamic Idealism, that of Leibnitz, 
723. 

Dyoor, 341. 

Eccard, 304. 

ElSos, 349. 

Egnazio, Giovanni Battista, 610 ; his 

" De Romanis principibus," 610. 
Elaterium, 655. 
Eleatic School, 93. 
Elementargeister, 730. 
Elements, the, according to Empedo- 

cles, Plato, and Aristotle, 362. 
Elimination, a method of, 413. 
Eloges of the French Academicians, 

550. 
Elwes, R. H. M., translator of Spinoza, 

192. 
Emotion and passion, not distinguished 

by Leibnitz and Locke, 751. 
Empedocles, 362; his four elements, 

362. 
" End organs " of nerves, 739. 
Ende, Francis Van der, 345. 
Endoxa, in Aristotle, 418. 
Enthymeme, 481. 
Entia rationis, 311, 759. 
'Eirixeipyna, what? 565. 
Epictetus, 496; his Aiarpipai, 496. 
Epicurus, 126, 421 ; literature of his 

life and philosophy, 421. 
Epigram, its nature, 481. 
Episcopius, Simon, 179,733; his "De 

libero arbitrio," 179. 
Equations: "ordinary" or algebraic, 



840 



LEIBNITZ'S CRITIQUE OF LOCKE 



425; "extraordinary" or transcen- 
dental, 425; reduction of, 571. 

Erasmus, 591, 592. 

Eratosthenes, 93. 

Erdmann, J. E., his " Leihnitii Opera 
Philosophica," xii, 3, 13, 14, 15, 16, 
19, 42, 46, 47, 49, 50, 52, 53, 56, 58, 
62, 63, 73, 80, 87, 89, 90, 91, 97, 101, 
118, 119, 120, 121, 123, 125, 127, 128, 
131, 136, 147, 150, 154, 155, 159, 167, 
174. 180, 185, 203, 204, 205, 210, 211, 
213, 218, 219, 220, 225, 227, 229, 239, 
240, 245, 246, 249, 251, 254, 257, 259, 
261. 263, 267, 270, 272, 273, 274, 275, 
282, 283, 284, 290, 293, 300, 301, 306, 
310, 314, 316, 317, 318, 319, 321, 323, 
326, 332, 333, 334, 341, 346, 349, 363, 
376, 379, 381, 382, 383, 386, 405, 412, 
414, 419, 420, 421, 434, 436, 437, 450, 
451, 460, 466, 476, 496, 497, 502, 504, 
50ii, 508, 511, 513, 537, 539, 548, 
551, 553, 561, 580, 588, 631, 632, 635, 
638. 644, 677, 687, 692, 693, 698, 705, 
706, 717, 721, 727, 731, 735, 749, 750, 
751, 752, 753, 766; " Gruudriss d. 
Gesch. d. Philos.," 67, 68, 129, 131, 
278, 303, 590. 

Erkenntnisslehre, 319, 633. 

Erinerins, F. Z., his " Hippocratis et 
aliorum uiedicorum reliquae," 476. 

Erpenius, 287. 

Esoteric teachings, 272. 

"Esprit," 28. " [768. 

"Ethereal vehicles" for spirits, 380, 

Ethics, its truths founded in natural 
theology, 496. 

Eucharist, Lutheran view of, 611. 

Eucken, Rudolph, his "Fundamental 
Concepts of Modern Philosophical 
Thought," 227, 239 ; his " Gesch. und 
Kritik der Grundbegriffe der Gegen- 
wart," 758; his "Die Grundbegriffe 
der Gegenwart historisch und kri- 
tisch entwickelt," 758. 

Euclid of Alexandria, 93 ; his response 
to Ptolemy, 93 ; commentators upon, 
108; his Elements reduced to syllo- 
gisms, 769 ; — of Megara, 93. 

Euler, Leonard, 393. 

Eutocius of Ascalonita, 465. 

Evolution, theory of, hinted at by 
Leibnitz, 347. 



"Exprofesso," 739. 

"Exception, some," 728. 

Exclusion, a method of, 413. 

Existence, what? 401. 

Existence of God, Descartes on, 502; 
Spinoza on, 502; Leibnitz on, 502; 
Anselmic argument for, 503. 

Exoteric teachings, 272. 

Experience, its incompetency, 725. 

"Experientia," its use among Scho- 
lastics, 724. 

Eye, "accommodation" of the, 228; 
men with only one, 389; Maurolico 
upon the, 442. 

Fabri, Honore, 586; disputes with Sen- 
nert upon the immateriality of the 
souls of animals, 488; his " Synopsis 
Geometrica," 586 ; his " Physica seu 
scientia rerum corporearuin," 586; 
his " Summula Theologian," 586; as- 
sists Divini in the controversy with 
Huygens, 614. 

Fabricius, John Lewis, 102; saves the 
Heidelberg archives, 102 ; his " Apo- 
logias generis humani contra calum- 
niam Atheismi," 102; letter to Spi- 
noza, 723. 

"Factum, in," 486. 

QavTaala, <pdvTa<T/j.a, 769. 

Farrar, F. W., his "Seekers after 
God," 496. 

Fedais, the devoted ones, 197. 

Feder, " Commercii epistolici Leibni- 
tiani," 728. 

Feeling, defined, 736 ; and ideas, their 
relations, 754. 

Felden, Johannes, 636. 

Feller, his " Otiuni Hanoveranum," 
595; edits "Miscellanea Leibniti- 
ana," 443. 

Felwinger, 635. 

Fergil, St., 443. 

Fermat, Pierre de, 213, 393, 465, 466, 
571 ; his " De Maximis et Minimis," 
465 ; " Opera Mathematica," 571. 

Ferrari, Luigi, 572 ; resolves equations 
of third and fourth degrees, 572. 

Ferri, L., his "La Psicologia di P. 
Pomponazzi," 581. 

Ferro, Scipione del, 571 ; solves cubic 
equations, 571. 



INDEX C 



841 



Feyerabend, 626. 

Fi'gmenta mentis, 623. 

Figure, syllogistic, the invention of 
the Fourth, 408. 

QCKocrbifyritxa, what? 565. 

Fiore, Antonio del, 571. 

Fire, as <pp6vi./xov, 729. 

Fischer, Kuno, his " Gesch. d. neuern 
Philos.," 218, 239, 363, 394, 421, 554, 
579, 584, 629, 752 ; his "Descartes 
and his School," 634. 

Florentines, 735. 

Fludd, Robert, his "Philosophia Mo- 
saica," 63, 730; his " Utrumque 
Cosmi," 730. 

Foerster und Koschwitz, their " Alt- 
frauzosisches Uebungsbuch," 294. 

Foutenelle, Bernard le Bovier de, his 
" Entretiens sur la pluralite des 
mondes," 550; his " Eloge de Leib- 
niz," 550; his "Dialogues des 
Morts,"551 ; " Doutes sur le systeme 
physique des causes occasionelles," 
551. 

Fontanier-Pellisson, Paul, 591 ; corre- 
sponds with Leibnitz, 591 ; his " His- 
toria l'Academie Francaise," 591 ; 
his "Traite de l'Eucharistie," 591; 
his "Reflexions sur les differends en 
matiere de religion," 591. 

*opd, 321. 

Force, primitive and derivative, 721. 

" Formalities," 569. 

Forms, substantial, their origin, 349; 
Locke's view of, 349 ; Leibnitz's view 
of, 349. 

Foucher de Careil, his "Lettres et 
opuscules ine'dits de Leibniz," xii, 
677, 748, 757; " Nouvelles lettres et 
opuscules inedits de Leibniz," xii, 
101, 420, 496, 728, 748, 750, 752, 775 ; 
his "CEuvres de Leibniz," xii, 532, 
544, 591, 592, 629, 737, 740, 757, 765 ; 
his " Leibniz et Pierre le Grand," 
629. 

Foucher, Simon, 420 ; " the restorer 
of the philosophy of the Academy," 
420; his "Critique de la Recherche 
de la Verite," 420 ; Malebranche crit- 
icises, 420 ; his objections to doctrine 
of Pre-established Harmony, 420 ; his 
correspondence with Leibnitz, 420. 



Fraser, Alexander Campbell, his 
"Locke," 56, 747; his edition of 
" Locke's Essay concerning Human 
Understanding," 549, 728, 730, 735, 
736, 737, 738, 747, 750, 755, 756, 760, 
762, 763, 765, 766, 767, 768, 769, 770, 
771, 772, 773 ; edits Berkeley, 747. 

Free-will, Leibnitz's definition of, 752. 

Freedom, ethical, distinguished from 
free-will, 752. 

Freigius, J., 311. 

French version of Locke's Essay, 728. 

Frenicle de Bessy, Bernard, a rapid 
calculator, 393 ; his method, 393; his 
"Traite des triangles et rectangles 
in nombres," 393. 

Frenicle, Nicolas, poet, 393. 

Friedlein, G., edits works of Proclus, 
108, 463. 

Fries, G. F., his "Neue Kritik der 
Vernunft," 764. 

Frisch, Ch., edits Kepler's works, 123. 

Froben, edits "Alcuini Opera," 546. 

Froidmont (Fromont) Libert, 234 ; his 
"Labyrinthus sive de compositione 
contiuui," 234. 

Fuchs, a botanist, 308. 

Gabelentz and Loebe, their " Ulfilas," 
296. 

Gaius, his "Elements of Roman Law," 
329, 434. 

Galenas Claudius, 407; his "De usu 
partium corporis hmnani," 407 ; his 
" Opera omnia," 408 ; invents fourth 
syllogistic figure, 408. 

Galileo, paves the way to formulation 
of law of gravitation, 440. 

Ganzarini, Tito Giovanni, il Scandi- 
anese, 399. 

Garner, R. L., on language of mon- 
keys, 764; his " Speech of Monkeys," 
764. 

Gass, W., his " Gesch. d. protestant- 
ischen Dogmatik ihrem Zusammen- 
hauge mit der Theologie," 589, 595. 

Gassendi, Pierre, 64, 65, 730; attacks 
doctrine of intentional species, 382 ; 
on Epicurus, 421; his "Syntagma 
Philosophicum," 421; " Gassendy," 
his Cinquieme Objections," 731; on 
vacuum, 774. 



842 



LEIBNITZ'S CRITIQUE OF LOCKE 



" Gaunersprache," its composition, 
292. 

Gaunilo, 502; his "Liber pro Insipi- 
enti," 503. 

Gauss, Carl Friedrich, his " Theo- 
ria motus corporum coelestium," 
152. 

Gautier, L., his "GEuvres Poetiques 
d'Adam de St.-Victor," 603. 

Gayard, his "Fragments relatifs a la 
doctrine des Ismaelis," 197. 

Genera and species, the philosophies 
of Locke and Leibnitz most sharply 
divergent on, 310. 

" Generation, spontaneous," 346. 

Genii, 52, 313. 

Gergo, 293. 

Gerhard, J., 587. 

Gerhardt, Carl Immanuel, "Die phi- 
losophischen Schril'ten von G. W. 
Leibniz," xii, 3, 10, 14, 15, 16, 26, 28, 
41, 49, 50, 53, 55, 56, 57, 65, 66, 72, 73, 
80, 87, 89, 90, 91, 97, 101, 105, 118, 
119, 120, 121, 123, 125, 128, 131, 136, 
147, 150, 154, 155, 159, 174, 180, 184, 
185, 199, 203, 204, 205, 210, 211, 213, 
218, 219, 220, 225, 227, 229, 239, 245, 
246, 249, 251, 254, 259, 263, 270, 272, 
273, 274, 282, 283, 284, 292, 300, 301, 
306, 310, 311, 314, 316, 317, 319, 321, 
323, 324, 330, 332, 333, 334, 341, 344, 
346, 348, 349, 362, 363, 376, 379, 3S1, 
382, 383, 386, 393, 394, 412, 420, 421, 
425, 434, 436, 437, 450, 451, 458, 460, 
463, 466, 478, 496, 497, 502, 504, 506, 
508, 511, 513, 520, 521, 522, 532, 537, 
548, 552, 553, 561, 576, 580, 586, 588, 
606, 623, 631, 633, 635, 638, 643, 644, 
651, 652, 653, 654, 655, 676, 677, 687, 
692, 693, 697, 698, 699, 705, 706, 714, 
715, 716, 717, 727, 728, 730, 731, 733, 
741, 748, 749, 750, 751, 752, 753, 754, 
755, 762, 766, 771 ; his " Einleitung," 
463 ; his " Sammlung des Pappus 
siebentes und achtes Buch," 521 ; 
"Leibniz, math. Schrift.," 573, 586, 
634, 657, 659, 670, 671, 676, 677, 683, 
684, 699, 733, 734, 767. 

Gerland, E., his " Leibuizens und Huy- 
gens Briefwechseln," 343. 

Gesner, Conrad, "the German Pliny," 
626; makes the first attempt at 



a literary encyclopedia, 626 ; his 
"Bibliotheca Universalis," 626. 

Gibbon, Edward, his "Decline and 
Fall of the Roman Empire," 197, 
345. 

Gilbert, William, earliest methodical 
experimentalist, 774; his "De mag- 
nete magneticisque corporihus," 774. 

Glanvill, Joseph, 631. 

Glass, Pliny on flexible, 316. 

Gobien, Charles A., 104; his " Histoire 
des Isles Mariannes," 104. 

Goclen, R., 311 ; his " Lexicon philoso- 
phicum," 311 ; his " Isagoge in Orga- 
num Aristotelis," 311 ; his regressive 
sorites, 311 ; mediates between Aris- 
totle and Ramus, 408. 

God, as place of things, 153; as actus 
purus, 159 ; omnipresence of, dyna- 
mic, 159; his veracity, its place in 
Cartesian system, 319; his existence 
required by doctrine of monads, 363 ; 
the scholastic distinction of will and 
understanding in, 462 ; object of 
man's highest moral aspiration and 
effort, 496; source of all truth and 
of all beings, 517. 

Godwin, Francis, his " Man in the 
Moon," 342, 551. 

Goebel, 602. 

Gobi, Jacob, 287, 468; his "Lexicon 
Arabico-Latinum," 287. 

Gottling, 379. 

Gombault, Antoine, 539. 

Gonzales, Domingo, his "Voyage chi- 
merique au monde de la lune," 342. 

Gonzalez, Tirso, opposed probahilism, 
418; his " Fundamentum Theologiae 
moralis, tractatus de recto usu opi- 
nionum probabilium," 418. 

Goodwin, W. W., his "Plutarch's 
Morals," 476. 

Goppert, his " Ueber einheitliche, 
zusammengesetzte und Gesammt- 
sachen nach rom. Recht," 759. 

Gorgias, 518. 

Goropius, see Becan. 

Gow, his ' ' Short History of Greek 
Mathematics," 527. [295. 

Graff, E. Th., his " Gospel of Otfrid," 

Grammatical confusion in the text ex- 
plained, 768. 



INDEX C 



843 



Grant, Alex., his "Ethics of Aris- 
totle," 321, 752, 753. 

Greaves, John, his " Pyramidogra- 
phia," 150. 

Green, when the product of blue and 
yellow, 320. 

Gregory, IX., 444; XIII., reforms the 
Calendar, 424. 

Grein, C. W. M., his " Bibliothek der 
Angel-Sachsischen Poesie," 295. 

Gretser, Jacob, 618; his response to 
magistrates of Marckdorf, 618. 

Grimaldi, Charles Philip, 394. 

Grimm, Jacob, his " Kleinere Schrif- 
ten," 294; his " Deutsches Worter- 
buch," 294. 

Groot, see Grotius. 

Grotefend, C. L., his " Briefwechsel z. 
Leibniz, Arnauld und Landgrafin 
Ernst, etc.," 463. 

Grotius, Hugo, 636; founder of phi- 
losophy of law, 494; on man as a 
social animal, 285; his " De Jure 
Belli et Pacis," 285; his "Epistolaj 
ad Gallos," 494. 

Ground-truths, theoretical, how con- 
scious of, 735; practical, how con- 
scious of, 735. 

Guericke, Otto von, 774; experiments 
on vacuums, 127 ; his air-machine, 
127; "Experimenta nova ut vocant 
Magdeburgica," 127. 

Guerre, Martin, the story of his per- 
sonation, 310. 

Guerrier, 629. 

Guhrauer, Dr. G. E., his " G. W. Frei- 
herr v. Leibnitz. Eine Biographie," 
xii, 213, 239, 334, 365, 394, 415, 434, 
435, 436, 532, 573, 591, 712, 715, 765 ; 
edits "Leibnitz's De principio Indi- 
vidui," 239, 606, 623; edits "Leib- 
nitz's deutsche Schriften," 7, 379, 
435, 602, 626, 736, 757, 764; his 
"J. Jung und sein Zeitalter," 636; 
edits Bodin's " Colloquium Hepta- 
plomeres," 648. 

Guyou, Mine., 728. 

Haaxman, biographer of Leeuwen- 

hoek, 346. 
Hadley, " Introduction to Roman 

Law," 329. 



Hagenbach, his " History of Doc- 
trines," 594, 729, 

Hakluyt Society, the, 89. 

Hamilton, Sir William, "Lectures on 
Logic," 14, 311, 317, 408, 515, 568; 
his "Reid," 50, 116, 136, 382, 463, 
576, 764; Note A, 43, 576; on the 
Infinite, 274; "Lectures on Meta- 
physics," 382, 734, 764. 

Hamm, Ludwig, 346. 

Hammer, Von, his " Gesch. d. Assassi- 
nen," 197. 

Hardy, Claude, his "Data Euclidis," 
465, 466. 

Harlay, Archbishop of Paris, 348. 

Harmony, Pre-established, 147, 319, 
363, 420, 759. 

Harris, W. T., "Journal of Specula- 
tive Philosophy," 8. 

Harrison-Verrall, his " Mythology and 
Monuments of Ancient Athens," 390. 

Harteustein, his "Locke's Lehre von 
der menschlichen Erkenntniss in 
Vergleichung mit Leibniz's Kritik 
derselben," 5,311 ; his " Hist. Philos. 
Abhandlungen," 311, 349 ; his edition 
of "Kant," 332. 

Harvey, William, 346. 

Harzer, P., his " Leibniz's dynamische 
Ausschauungen," etc., 775. 

Hashishin, 197. 

Hasse, his ' ' Anselm von Canterbury," 
503. 

Haureau, Barthelmy, his "Histoire de 
la Philosophic Scholastique," 349, 
382, 503, 588 ; his " De la philosophie 
scholastique," 767. 

Haurisius, his " Scriptores Historian 
Romanse Latini veteres qui extant 
omnes," 610. 

Heath, James, his "Flagellum; or 
Life and Death, Birth and Burial of 
Oliver Cromwell," 543. 

Hebrew in Gaunersprache, 292. 

Hedge, F. H., in " Journal of Specula- 
tive Philosophy," 101, 154, 332. 

Heereboord, Adrian, 633. 

Hegel, his "Gesch. d. Philos.," 108, 
156; on Boehme, 298; his "Vorles- 
ungen iiber Beweise von Dasein 
Gottes," 503; emphasizes like Leib- 
nitz the concrete, 749; agrees with 



844 



LEIBNITZ'S CRITIQUE OF LOCKE 



Leibnitz's view of absolute, 750; in- 
terprets Leibnitz's Principle of Indi- 
viduation, 766. 

Heidegger, J. H., edits works of Fab- 
ricius, 102. 

Helmont, Francois, Mercure van, 67, 
101, 242; his " Opuscula philoso- 
phical' 242; his relations with Leib- 
nitz, 242 ; Leibnitz writes his epitaph, 
242; physician of the Countess of 
Connaway, 732 ; — John Baptiste 
van, 645. 

Hendriks, Frederic, his " Contributions 
to the History of Insurance," 540. 

Henke, E. L. Th., his " Georg Calixtus 
unci seine Zeit," 5S2. 

Heppe, his " Gesch. d. Pietismus," 602. 

Heraclitus, 729. 

Herbart, J. F., on "working over of 
notions," 463. 

Herbell, J. F. M., translator of 
Camper, 286. 

Herbert of Cherbury, Lord Edward, 
587; his " De Veritate," 95. 

Herlinus, Christian, collaborator with 
Dasypodius upon the " Analyses 
Geometricae," 404 ; Hamilton's opin- 
ion of, 769; where examples of the 
Analysis of, may be found, 769. 

Hermathena, of Trinity College, Dub- 
lin, 108. 

Herodotus, 389, 547. 

Herostratns, the incendiary, 536. 

Hertz, Wilhelm, 67. 

Herzog, his " Realencyclopadie," 296, 
587, 592, 595. 

Higginson translates Epictetus, 496. 

Hippocrates, of Chios, 527 ; determines 
area of lune, 527 ; — of Cos, 476, 527 ; 
"Father of Medicine," 476; based 
practice of physic on observation, 
476; enforced dietetics, 476; his 
Aphorisms, 476 ; his abjx-wvoia iravra, 
conspirantia omnia, 476. 

Hispanus, Petrus, 322. [50, 68. 

" Histoire des Ouvrages des Savants," 

Hobbes, Thomas, 93, 285, 450 ; his " De 
Corpore," 93 ; his ' ' Six Lessons to the 
Professors of Mathematics," 93 ; his 
" De Cive," 285; his "Leviathan," 
285, 450 ; his doctrine of Society, 
285 ; on truth, 450 ; a Nominalist, 



450; literature upon the teachings 
of, 450; his "Leviathan" censured 
by Parliament, 775. 

Holden, Henry, his " Divinae Fidei 
Analysis," 617 ; his controversy with 
Arnauld, 617. 

Holtzendorff and Virchow, their 
" Sammlung wissenschaftlicher Vor- 
trage," 425. 

Hommeite, "mau-ness," 369. 

Honestum and utile, 261. 

Honorius, his " gallus pugnax," 610. 

Hooghelande, Cornelius Van, 633. 

Hooke, Robert, his " Micrographia," 
639. 

Hooker, Richard, his " Laws of Eccle- 
siastical Polity," 566. 

Hoole, Samuel, translator of Leeuwen- 
hoek," 346. 

Horace, "Epistles," 87, 328, 566; 
"Satires," 335. 

Hottentots, language of, 290. 

Hughes, his " Loyola, and the Educa- 
tional System of the Jesuits," 619, 

Hugony, 9. 

Hultsch, F., his " Pappi Alexandrini 
Collectiones quae supersunt," 521. 

Humanities, 628. 

Hume, accords with Leibnitz on basis 
of morals, 735 ; " Inquiry concerning 
the Principles of Morals," 735; his 
"Treatise of Human Nature," 736; 
on Causes, 757. 

Hunt, T. W., his " Caedmon's Exodus 
and Daniel," 295. 

Huygens, Christian, 150, 213, 539, 676, 
723 ; his " Traite' de la Lumiere, " 150 ; 
discovers double refraction, 150; 
places the wave theory of light on a 
sure foundation, 150; applies the 
pendulum to the clock, 150 ; his " De- 
scription de l'horloge a pendule," 
150 ; experiments on the isochronous 
pendulum, 150; his " De Ratiociniis 
aleae ludo " 539; his " Cosmo theo- 
ros," 550; his speculations concern- 
ing planets, 550 ; controversy with 
Divini, 614 ; his " De motu corporum 
ex percussione," 676; his " OEuvres 
completes," 723. 

" Hypothesis physica nova," its struct- 
ure, 677. 



INDEX C 



Ibn-al-Baitar, see Baitar. 

Idatius, Chronicle of, 99. 

Idea, 330. 

Ideas, their natural order, 289; pure 
truths of reason, 325 ; their content, 
325 ; their realization, 325 ; in what 
sense " true " or "false," 452; in 
Divine Mind as rationes rerum sta- 
biles et incommutabiles, 516; in- 
nate, their criterion, 733; simple, 
mind active in reference to, 763. 

Idee, 330. 

Identitatis, principium, 569 ; indis- 
cernibilium, principium, 332. 

"\Slov, 455. 

Idola Fori, omnium molestissima, 306. 

Illyricus, Matthias Flacius, 294. 

Image and Idea, 274. 

Immams, 197. 

Immediate Revelation of God to Soul, 
Locke's statement concerning, 474. 

In factum, an action at law, 486. 

Incessabilite, 245. 

Indefinite-infinite, 162. 

Independents, 600. 

Indirect demonstration, 406, 491. 

Indiscernibles, principle of, 332. 

Individual, the, its existence alone 
allowed by Locke, 567. 

Individualism, nominalistic, 623. 

Individuation, principle of, 239. 

Inductive conclusions founded on 
" truths of fact," 493. 

Infants, concerning their salvation, 
594. 

Infinite, the syncategorematic and cat- 
egorematic, 161, 162; whence the 
errors and difficulties in discussion 
of, 274; cannot form an image of, 
274 ; knowledge of the, denied, 274 ; 
" trois sens du mot," 750. 

Infinite series, 424. 

Infinitesimal calculus, its application 
in Newton's "Principia," 440; dis- 
covery of, 573. 

Infinitivum, indefinitum, 162. 

" Inner Light " defined, 599, 773. 

Inspiration, Divine, gives " lumen 
Gratiae," 576; regarded as associ- 
ated with mental derangement, 598. 

"Instinct," how used by Leibnitz, 
735. 



Insurance, John de Witt, its first sci- 
entific propounder, 540. 

Intelligence, The Supreme, His rela- 
tion to ideas, 763. 

Intuition, immediate, of Plato, 575. 

"Inward Light" of William Penn, 
602. 

Ionic School of Philosophy, 519. 

Jackson, H., on the SaL/xoviov of Soc- 
rates, 598. 

Jacoby, D., his "De Leibnitii studiis 
Aristotelis," 753. 

Jacques, Amedee, his " GEuvres de 
Leibniz," xii, 42, 46, 47, 49, 50, 53, 
56, 58, 62, 63, 73, 80, 87, 89, 90, 91, 
97, 101, 118, 119, 120, 121, 123, 125, 
147, 150, 154, 184, 185, 203, 204, 205, 
210, 211, 213, 218, 219, 240, 245, 246, 
249, 251, 254, 257, 259, 263, 267, 270, 
273, 274, 275, 282, 283, 284, 290, 298, 
300, 301, 310, 314, 316, 321, 323, 326, 
332, 333, 334, 346, 349, 352, 363, 381, 
382, 383, 386, 405, 412, 414, 460, 466, 
476, 496, 497, 504, 506, 50S, 511, 522, 
537, 548, 550, 551, 553, 580, 588, 705, 
727, 750, 751, 754, 766, 768. 

" Jalkut Chadasch," 242. 

James, W., his "Psychology," 760. 

Jancourt, his " Historia vitse Leib- 
nitii," 573. 

Janet, " G5uvres philosophiques de 
Leibniz," 73, 451, 463, 705, 727, 734, 
735, 738, 739, 740, 741, 749, 750, 751, 
754, 756, 760, 761, 762, 763, 764, 765, 
766, 768, 769 ; his " La Morale," 418. 

Janney, his "Life of William Penn," 
602. 

Jansen, H. C., translator of Camper, 
286. 

Je ne say quoi, applied to ultimate 
essence of things, 128. 

Jebal, Sheik-al, 197. 

Jenichen, J. A., 626. 

Jerome, his "Ad Ctesiphontem," 345. 

Jerome de la Lande, 551. 

Jesuits, 418. 

Jevons, W. S., his "Principles of Sci- 
ence," 214 ; " Lessons in Logic," 322 ; 
his " Substitution of Similars," 569. 

Jocher, his " Allgemeines Gelehrten- 
Lexicon," 403, 585, 586. 



84G 



LEIBNITZ'S CRITIQUE OF LOCKE 



"Journal," "des Savants," 15, 101, 
420, 507; "of Speculative Philoso- 
phy," 8, 101, 332 ; " for Math.," 
Crelle, 571 ; " of Philology," 598. 

Jowett, translator of " Politics of Aris- 
totle," 285,482; translator of "Dia- 
logues of Plato," 291, 292, 298, 390. 

Julius, Duke, his decision in the case 
of Martin of Helmstadt, 582. 

Jung, Joachim, G36. 

Jurists, the Roman, Leihnitz's opinion 
of, 415. 

Jus accrescendi, 434. 

Jus non ex regula sumatur, sed ex 
jure, 487. 

Justin Martyr, his " Apologies," 591 ; 
his " Spermatic Logos," 591. 

Justinian, his "Institutes," 434, 487, 
492, 591; his "Codex," 497. 

" Kabbala " on pre-existence of souls, 
250; "Denudata," 732. 

Kadlubek, Vincent, his "Historia 
Polonica," 546. 

~Ka()6\ov TTp&rov, 488. 

Kalbkopf , see Moscherosch. 

Kant, his " Kritik d. prakt. Ver- 
nunft," 184; his "Die Religion in- 
nerhalb der grenzen der blossen 
Vernuuft," 248; his "Kritik d. rein. 
Vernunft," 128, 332, 503, 733; " Di- 
lucidatio nova," 332 ; his a priori 
(necessary and universal) and a 
posteriori (contingent and actual) 
thought, 725 ; his Kategories or 
original notions of the understand- 
ing, 726, 737, 741 ; on truths of 
reason, 733 ; refers to Copernicus, 
733; his reason practical, 754; his 
definition of "virtue," 754; his 
ground of faith in immortality, 755. 

Keckermann, Barth., 311 ; his proof of 
Trinity, 589 ; his " Systema ss. Theo- 
logize," 589; his "Opera omnia," 
589. 

Kelle, J., his " Gospel of Otfrid," 295. 

Kepler, John, 123 ; his " Somnium seu 
de Astronomia lunari," 551. 

Kerkkrinck, Theodore, his " Anthro- 
pogenise Ichnographia," 345. 

Kessler, Andreas, his " Physicas Pho- 
tiniame Examen," 586 ; his "Meta- 



physical Photinianae Examen," 586; 

his "Logicse Photiniana; Examen," 

5S6. 
Kestner, his " Medicinisches Gelehrten- 

Lexicon," 521. 
King, his " Life and Correspondence 

of Locke," 728. 
Kings, L, 8:27, 158. 
Kirchmann, J. H. von, his " Philos. 

Biblioth.," 125, 227, 239, 286, 349, 504, 

540, 552, 555, 613, 732, 739, 748, 754; 

his "Die klein. philos. wichtig. 

Schrift. v. G. W. Leibniz," 218, 227, 

239, 722, 723; " Erlauterungen zu 

J. Locke's Versuch. ii. d. menschl. 

Verstand," 555 ; his " Erlauterungen 

zur The'odicee," 751, 758. 
Kirchner, his " Leibniz's Psychologie," 

752. 
Kleutgen, his " Philosophie d. Vor- 

zeit," 382. 
Klopp, O., his "Die Werke v. Leib- 
niz," 239. 
Knowledge, mediate and immediate, 

109; its relation to Kant's division 

of, 109 ; of senses, how classified, 317. 
Konig's " Appel," 713. 
Kortholt, Christian, his " Leihnitii 
• Epist. ad diversos," 415, 486, 606, 

631, 632, 748 ; — Sebastian, Leibnitz's 

letter to, 436. 
Koschny, Erick, 218. 
Kotter, C, 604. 
Krafft, his " Kirchengesch. d. deutsch. 

Volker," 296. 
Krauth-Fleming, their " Vocabulary 

of Philosophical Sciences," 125, 136, 

330, 363. 
Kuhlmann, Quirin, his hallucination 

and fate, 601. 
Kummer, his " Festrede am Leibniz- 

tage," 425. 

Labadie, Jean de, 602. 

Labadists, 602. 

Labbe, Philippe, 293; his "Concordia 

chronologica, technica et historica," 

293; his " Eruditse pronuntiationis 

catholici indices," 293. 
Lacoste, Bertrand- de, his "Scheda de 

inventa quadratura circuli," 604. 
Lactantius, 327. 



INDEX C 



Laertius, Diogenes, his " De vitis, dog- 
matibus, et apophthegmatis claro- 
rum philosophorum libri decern," 
385, 518, 519. 

Lagrange, Jos. Louis, 393. 

Lallemant, Ave, his "Das deutsche 
Gaunerthum," 292. 

Lambert of Auxerre, his " Summa 
Logic se," 322. 

La Mothe le Vayer, Francois de, 593 ; 
his " De la vertu des pa'iens," 593. 

Lang, Andrew, his " Myth, Ritual and 
Religion," 85. 

Lange, his " Gesch d. Materialismus," 
363, 421, 592, 727, 730, 774 ; his article 
" Vives," in "Encykl.d. ges.Erzieh. 
-u. Unterrichtswesen," 592. 

Langley, Alfred G., his article, "Reve- 
lation, Inspiration and Authority," 
in " Andover Review," 32, 195. 

Language, an aid to society, 286; of 
apes, 286; Leibnitz's mistake as to 
its origin, 288; involves advance to 
abstract ideas, 290; early discus- 
sions upon, 291 ; Leibnitz upon for- 
mation of, 292; modern discussions 
upon, 292 ; philosophical, 292, 375. 

Languages, Leibnitz's presentiment of 
their connection, 297; the compara- 
tive study of, recommended, 298. 

Laplace, his "Theorie analytique des 
probabilites," 213. 

Larousse, P., his " Dictionnaire uni- 
versel du XIXe siecle," 310, 443, 494, 
527, 539. 

Lasiks, 197. 

Lasswitz, his " Gesch. d. Atomistik," 
632, 633, 635, 636, 639, 645, 646, 648, 
676, 684, 723, 727, 730, 732, 735, 740, 
751, 752, 771, 774. 

Lateran Council, the fifth, 581. 

"Latio," (popd, 321. 

Laurie, S. S., his " Comenius," 466. 

Leclerc, his " Bibliotheque universelle 
et historique," 26. 

Leeuwenhoek, Anton van, discovers 
spermatozoa and capillary circula- 
tion, 346; opposes "spontaneous 
generation," 346. 

Leibnitz, Gottfried Wilhelm; his 
" Meditationes de Cognitione, Veri- 
tate et Ideis," 3, 14, 17, 227, 266, 



317, 363, 404, 502 ; his correspondence 
with Bierling, 3, 101, 131, 436, 542, 
721, 748 ; his correspondence with 
Burnet, 6, 7, 382, 458, 478, 599, 728; 
anonymous letters of, 8, 712; cor- 
respondence with Coste, 9; cor- 
respondence with Remond, 9, 101, 
131, 731; correspondence with Lady 
Masham, 9, 65 ; titles given by him- 
self to his review of Locke's Essay, 
9, 10, 65; his use of parentheses in 
"Nouveaux Essais," xiv, 10; his 
" Eclaircissement des difficultes que 
M. Bayle a trouvees dans le systeme 
nouveau de l'union de l'ame et du 
corps," 50; his remarks on "Rora- 
rius," 66, 507; his " Considerations 
sur la Principe de Vie et sur les 
Natures plastiques," 67, 68, 363, 731 ; 
his relation to Spinoza, 69 ; his " Sys- 
teme nouveau de la nature," 101, 
147, 154, 346, 349, 363, 733 ; his " Res- 
ponse sur reflexions contenues clans 
la seconde edition de Dictionnaire 
critique de M. Bayle," 101, 333, 508, 
539; his correspondence with R. 
Ch. Wagner, 101, 131, 379, 550, 559; 
his correspondence with Fardella, 
101 ; his correspondence with Dan- 
gicourt, 101 ; his correspondence 
with Arnauld, 101, 334, 426, 463, 553, 
739; his " De ipsa natura," 101, 154, 
21S, 332, 349, 383, 705; correspon- 
dence with Des Bosses, 101, 128, 131, 
155, 229, 341, 740; correspondence 
with De Voider, 101 ; correspondence 
with Bourguet, 101, 213, 436, 561 ; 
correspondence with von Hessen- 
Rheinfels, 101; his " Un petit dis- 
cours de Metaphysique," 101, 261, 319, 
330, 349, 496, 553, 554 ; his " Specimen 
dynamicum pro admirandis naturse 
legibus," 101, 174, 383, 670, 733, 751; 
his "Principe de la Nature," 101; 
his " La Monadologie," 101, 225, 332, 
502, 511, 733; his correspondence 
with Clarke, 128, 332, 381, 383, 553, 
749, 750 ; correspondence with Tolo- 
mei, 131 ; his " De anima brutorum," 
131; his "Principes de la nature et 
de la grace fondes en raison," 136, 346, 
363, 502; his "Codex juris gentium 



848 



LEIBNITZ'S CRITIQUE OF LOCKE 



diplomaticus," 167, 495, 496, 750; his 
"De notionibus juris et justitiae," 
167; his " De primse philosophiae 
emendatione," 154, 174; his corre- 
spondence with Fabri, 174, 586, 676, 
699, 751 ; his " Essais de Theodicee," 
180, 227, 239, 310, 333, 334, 349, 382, 
383, 415, 450, 496, 508, 511, 551, 553, 
576, 581, 582, 585, 586, 587, 589, 590, 
592, 594, 595, 602, 606, 635, 752; 
on logic of probabilities, 213; ac- 
quainted with Pascal's investigations 
on probabilities, 213; on creation, 
225 ; his correspondence with Bayle, 
225, 261, 334 ; his " Disputatio Meta- 
physica de principio individui," 239, 
606, 623 ; correspondence with Sophie 
Charlotte, 239, 748; his "Miscel- 
lanea," 242, 4:;r>, 443, 539, 590; his 
"De stilo philos. Nizolii," 272, 450, 
588, 623; his correspondence with 
Geheirnrath von Ilgen, 293 ; his corre- 
spondence with Fr. S. Loeffler, 298; 
was an idealistic realist, 319; his 
"Animadversiones in partem gener- 
alem principiorum Cartesianorum," 
334, 363, 504 ; his views of substan- 
tial forms, 349; "Leibniz gegen 
Descartes und den Cartesianismus," 
363 ; on Pythagoras, 379 ; his opinion 
of formal Logic, 379, 559 ; his corre- 
spondence with G. Wagner, 379, 559 ; 
correspondence with Placcius, 382, 
435, 520 ; correspondence with editor 
of " Journal des Savans," 383; cor- 
respondence with Alberti, 383; cor- 
respondence with Thomasius, 383, 
606, 631, 769; correspondence with 
Hobbes, 387, 450; correspondence 
with Kestner, 415, 417, 436, 486; 
his "Epist. ad diversos," eel. Kor- 
tholt, 417, 486, 748 ; correspondence 
with S. Kortholt, 436, 438, 649, 748 ; 
correspondence with Foucher, 420, 
677; correspondence with Male- 
branche, 421 ; his infinite series, 424 ; 
his infinitesimal calculus, 424, 573 ; 
correspondence with Coining, 425, 
504, 520, 521, 769, 771; his " De vera 
proportione circuli ad quadratum 
circumscriptum in numeris ration- 
alibus," 425; his "Thesis de con- 



ditionibus," 434; his " Specimina 
Juris," 434; his " De Arte Com- 
binatoria," 434, 561; on Weigel, 
435 ; his criticism of Puf endorf , 436 ; 
his "Monita quaedam ad S. Puffen- 
dorfii principia," 436 ; his " Pre- 
cept es pour avancer les sciences," 
437 ; a philosophical fragment, 437 ; 
his "Reflexions sur 1'ouvrage que 
M. Hobbes a publie de la liberte, 
de la necessite et du hazard," 450, 
451; on Revelation, 474; his "Uni- 
cum opticas catoptricae et dioptricae 
principium," 484; his "Nova me- 
thodus discendae doeendaaque juris- 
prudentioe," 486 ; his " Nouvelles 
lettres et opuscules inedits," by 
Foucher de Careil, 496 ; on rela- 
tion of Natural Theology to Meta- 
physics, 496 ; his letter to Electress 
Sophie, 496 ; source of ethical truth 
according to, 496; his " Definitiones 
ethicae," 496; on ontological argu- 
ment for existence of God, 502 ; 
his doctrine of Monads requires ex- 
istence of God, 502 ; his " De la de- 
monstration Cartesienne," 502, 504; 
his " Confessio Naturae contra Athe- 
istas," 502 ; his correspondence with 
Jacquelot, 504; his correspondence 
with Eckhard, 504; his " Probatio 
existientiae Dei ex ejus essentia," 
504 ; correspondence with Basnage de 
Beauval, 507, 727; his "Observatio 
ad rescensionem libri de fidei et rati- 
onis consensu a Domino Jacqueloto 
editi," 511; his "De modo distin- 
guendi phenomena realia ab imagi- 
nariis," 513 ; regarded idea of God as 
constitutive, 517 ; regarded idea of 
God as principle of all thought, 517 ; 
regarded actuality of God as consti- 
tutive principle of all things, 517 ; 
his correspondence with Bossuet, 
544; his " Introductio in collec- 
tionem Scriptorum Historiae Bruns- 
vicensi inservientium," 546 ; his 
correspondence with Tentzel, 553; 
his " Response aux objections contre 
le systeme de l'harmonie preetablie 
qui se trouvent dans le livre de la 
connoissance de soy-memes," 553; 



INDEX C 



849 



his "Systema Theologicum," 554; 
his correspondence with Hartsocker, 
554,740; his "AnnotatiunculaB subi- 
tanese ad Tolandi librum," 554, 579 ; 
his views of miracles, 554 ; his " Di fa- 
cilitates qusedam logicse," 561; his 
controversy with Newton, 573 ; his 
"Historia et origo calculi differen- 
tialis," 573 ; his correspondence with 
Countess Kielmannsegge, 573; his 
"Hypothesis physica nova," 586; 
his "Theoria motus abstracti," 586, 
634; his views of the Trinity, 590; 
his "Defensio Trinitatis," 590; his 
" Duse Epistolse ad Loeflerum," 590; 
his "Remarques sur le livre d'un 
Antitrinitaire Anglois," 590; letter 
to M. B., 590; his correspondence 
with Pellisson, 591, 592 ; his corre- 
spondence with Magliabechius, 592 ; 
his correspondence with Fabricius, 
592 ; his " Sur l'esprit sectaire," 600 ; 
his correspondence with Spizel, 602 ; 
his correspondence with Wolf, 606; 
on Nominalism, 623 ; his " Idea Leib- 
nitiana Bibliothecpe Publicse," 626; 
his " Representation au Due de 
Wolfenbuttel pour l'encourager a 
l'entretien de sa Bibliotheque,'"' 626; 
his relations with Peter the Great, 
629, 740; his "Theoria motus con- 
creti," 634, 733 ; correspondence 
with Spener, 649 ; correspondence 
with Huygens, 676, 767 ; corre- 
spondence with Wallis, 677 ; his 
comparison of himself to Plato, and 
of Locke to Aristotle investigated, 
723, 724; his "Remarques sur le 
Sentiment de M. de Worcester et 
de M. Locke," 728; is "inclined 
towards ethics," 731 ; eclectic in 
thought, 731 ; his "Animadversiones 
circa Assertiones aliquas Theorise 
Medicae vera? Clar. Stahlii," 733; 
his " Vermischte Bemerkungen und 
Urtheile," 736 ; correspondence with 
Leuwenhoek, 740 ; his " Observa- 
tions iiber die Magnet-Nad el," 740; 
correspondence with Guericke, 741 ; 
his "De Libertate," 752; on Made- 
moiselle de Scudery, 757 ;' his " Ob- 
servations de Principio Juris," 



761 ; his " Bedenken welchergestalt 
den Mangeln des Justiz-Wesens in 
theoria abzuhelfen," 764 ; letter 
from Burckhardt to, 766; corre- 
spondence with Gackenholtzius, 766; 
his " Critical Essay on the Story of 
Balaam," 767. 

Lemnius, Levinus,448; his " De rnira- 
culis occultis naturae," 449. 

Lessing, his " Theolog. Streitschrif- 
ten," 194; his statement regarding 
search after truth vindicated, 194, 
195; his " Erziehung des Menschen- 
geschlechtes," 248; his " Dass mehr 
als fiinf Sinne fur den Menschen 
sein konnen," 584. 

Lessius, quoted by Pascal, 749; "De 
justitia et jure," 749; his theological 
works, especially on Freedom of 
Will, 749. 

Library, Leibnitz on its classification 
and catalogue, 626. 

Libri, his " Histoire des Sciences ma- 
thematiques en Italie," 572. 

Liceti, Fortunio, on monsters, 351; 
Guiseppe, on monsters, 351. 

Light, Aristotle's definition of, 321; 
the inner, 591 , 599. 

Lignum nephriticum, 769. 

Limborch, 733. 

Lincoln, J. L., his "Marcus Aurelius 
Antoninus," 771. 

Lindemann, demonstrates non-alge- 
braic character of w, 425. 

Linden, J. A. van der, his " De scriptis 
medicis," 521. 

Linea prseclicamentalis, 322. 

Lipenius, Martin, his various " Biblio- 
thecae reales," 626 ; his use of realis, 
626. 

Littre, his " Dictionnaire de la langue 
francaise," 191, 757; his " OSuvres 
completes d'Hippocrate," 476. 

Lobeira, Vasco de, his "Amadis de 
Gaul," 399. 

Locke, John, his "Essay" translated 
and summarized in "Bibliotheque 
Universelle," 4; editions of his 
"Essay," 4; his"Essay" translated 
by Coste, 4 ; his " Thoughts on Edu- 
cation, 5 ; " Some Familiar Letters " 
of, 5, 6 ; correspondence with Moly- 



850 



LEIBNITZ'S CRITIQUE OF LOCKE 



neux, 6, 747; his philosophy con- 
trasted with that of Leibnitz, 310, 
723; his view of substantial forms, 
349 ; on truth, 452 ; on religion, 
474; his view of reason, 555; his 
sensistic realism, 567 ; his "Exami- 
nation of Malebranche," 578 ; on rea- 
son and faith, 579; his controversy 
with Stillingfleet, 728; his idea of 
creation of matter, 772. 

Logic, formal, the views of Locke and 
Leibnitz regarding, 555, 559, 561 ; its 
function, 555. 

A670S, its part in formation of society, 
286 ; defined, 555. 

Long, George, his translations of the 
" Thoughts of Aurelius Antoninus," 
and of the "Discourses, Encheiri- 
dion and Fragments of Epictetus," 
496. 

Loubere, La, Simon, 60. 

Lucan, " Pharsalia," 144. 

Lucian, his "Lucius or Ass," 243; his 
" True Histories," 399. 

Ludolph, see Ceulen. 

Ludolphe, John Job, his " Tetragono- 
metria Tahularia," 75. 

Ludolphische Zahl, 734. 

Lully, Raymond, his "Tabula Logica," 
322; inventor of the "Great Art," 
590; his "Articuli Fidei Sacro- 
sanctas," 590. 

Lumen, naturale, 576 ; gratis,, 576. 

Lunafixa, 324. 

Lune, first curvilinear space whose 
area was determined, 527. 

Luz, nS, the incorruptible bone of the 
Rabbis, 242. 

" Lyra Germauica," 586. 

Lycosthenes (Wolffhart), 548. 

Maass, Johann G. E., 764. 

Machine (i.e. body), a term among 

Cartesians, 348. 
Madvig, his edition of Cicero's "De 

Finibus," 272. 
Magnet, Leibnitz on. 740. 
Magnitude, Imperfect, what? 761. 
Magot, 342. 

Mahcr, his " Psychology," 382. 
Mahaffy, J. P. his " Descartes," 

727. 



Maimbourg, his " Histoire du Luthera- 
nisme," 544. 

Majority of professors, argument 
from, 531. 

Malebranche, Nicolas, his "De la Re- 
cherche de la Ve'rite'," 64, 176,421; 
on " seeing things in God," 153; his 
"Traite de la communication du 
mouvement," 176 ; opposed by 
Regis, 348; his change of view, 752. 

Malpighi, 346. 

Man, a selfish or a social animal ? 285. 

Mancini, his monograph on Valla, 415. 

Man-ness, as a translation of hom- 
meity, 369. 

Mansel on the Infinite, 274 ; on limita- 
tion of axioms, 770. 

Marci von Kronland, Johannes Mar- 
cus, 676. 

Marinus, Neo-Platonist, and commen- 
tator on Euclid, 465. 

Mariotte, Edme, 121; discovers blind 
spot in retina, 121. 

Mark 7: 11-13, 327. 

Markham, Clements R., translator of 
Garcilasso de la Vega, 89. 

Martineau, James, his " Types of 

• Ethical Theory," 153, 421 ; his 
"Study of Spinoza," 633; a mis- 
take of his, 633. 

Masham, Lady, 65, 730. 

Mass, what? 722. 

Massa perditionis, infants naturally 
a part of, according to Augustine, 
594. 

Massmann, H. F., his "Die kleinen 
Sprachdenkmale des VIII bis XII 
Jahrhundert," 294; his "Ulphilas,'' 
296. 

Materia prima, 110. 

Mathematics as science of magnitude 
applicable only to sensible things, 
756. 

Matthew 5 : 5, 6, 327. 

Matter, primary and secondary, 131 ; 
can it think? 427; what? 722; sub- 
tile to infinity, 722. 

Maupertuis, his charge against Konig, 
713. 

Maurier, Louis Aubery du, his Dutch 
" Memoires," 542. 

Maurolico, Francesco, his "Treatise 



INDEX C 



851 



on Conies," 442; his " Problemata 
ad perspectivam et iridem perti- 
nentia," 442; his "Theodosii sphaB- 
ricorum," 442; his " Photismi (or 
Theoremata) de lumine et umbra," 
etc., 442. 

Maywald, M., his "Die Lehre v. d. 
zweifachen Wahrheit," 581. 

Mechanism, its source, 721. 

M'.dius terminus, 481. 

Megarian School of Philosophy, 93. 

Meier, Gerhard, 304, 7G5. 

Melancthon, 592. 

Membranes, what Leibnitz meant by? 
740. 

" Memoires de Trevoux," 444, 502. 

Menage, Gilles, his " Dictionnaire 
etymologique de la langue fran- 
caise," 344. 

"Menagiana," 350. 

"Mentor, the," a magazine published 
by the blind, 747. 

" Mercure galant," 438. 

Mere, Chevalier de, 213; his "Agre- 
mens," 539. 

Merkelius, editor of Ovid, 211. 

Mersenne, 410; his " Synopsis," 465. 

Merz, J. T., his " Leibniz," 307, 629. 

Merzeriac, Bachet de, 571. 

Metempsychosis, Aristotle opposes, 
760. 

Meyer, H. A. W., "Kommentar," 327. 

Michaud, his "Biographie Univer- 
selle," 404, 418, 520, 546, 551; his 
" Histoire des Croisades ," 197. 

Microcosm, 109. 

Middle term, 770. 

Migne, his " Theologiae Cursus com- 
pletus," 749; his " Patrologise Cur- 
sus completus," 345, 443, 502, 516, 
546, 618, 737. 

Milky Way, the successful conjecture 
of Democritus concerning, 277, 763. 

Mill, J. S., his " Logic," 213, 769. 

"Mind," 69. 

Mind, what we know in, 721. 

Minute perceptions, the value of 
Leibnitz's teachings on, 727. 

Miracles, Leibnitz's attitude towards, 
606, 607. 

Mnemonics, their alleged invention, 
214. 



"Modes," Descartes on, 748; mixed, 
their formation according to Locke, 
757, 768. 

"Mola,"344. 

Moliere, his "Don Juan ou le Festin 
de Pierre," 536. 

Molyneux, William, founded Dublin 
Philosophical Society, 138; his "Di- 
optrica Nova," 138, 484; his corre- 
spondence and relations with Locke, 
747. 

Mommsen, Theodore, his edition of 
the "Digests." See Corpus Juris 
Civilis. 

Monad, the term whence borrowed, 
101 ; where first mentioned, 101 ; the 
writings of Leibnitz in which men- 
tioned, 101; the primitive, 722; the 
derivative, 722; how divided, 722; 
inextinguishable, 722; the created, 
endowed with an organic body, 722 ; 
contains the entelechy, 722; like 
mirror, 738. 

Monadology not pantheistic, 732. 

Monatliche Auszug, 26. 

"Monist, the," 425. 

Monists, Leibnitz, Spinoza, and Locke 
were in different ways, 757. 

Montagne, Vieux de la, 197. 

Montferrat, Conrad of, 197. 

Montalvo, Garcia Ordonez de, 309. 

Montucla, his "Histoire des Mathe- 
matiques," 572, 573. 

" Monumenta Germanise Psedago- 
gica," 619. 

Moon daemons, 551. 

Moral Law, Leibnitz's view of, 262; 
E. G. Robinson's view, 262. 

Moral Philosophy, Pythagorean prin- 
ciple applied to, 435. 

Morality, according to Hume, "de- 
pends on some internal sense or feel- 
ing," 735, 736. 

More, Henry, his theory of pre-exist- 
ence of souls, 250 ; on aerial vehicles, 
380 ; his principium liylarchicum or 
Spiritus naturse, 382 ; his friendship 
with the Viscountess Conway, 732. 

Moreri, his mistake, 539. 

Morhof, his " Polyhistoria," 636, 650. 

Morley, Henry, his "English Writers," 
295. 



852 



LEIBNITZ'S CRITIQUE OF LOCKE 



Moscherosch, John Mich., his " Ge- 

sichte Philanders von Sittenwald," 

293. 
Motion, Aristotle on, 320; the source 

of laws of, 721. 
Mouton, Gabriel, invents " Method of 

Differences," 150; his "Observa- 

tiones diametrorum solis et lunse 

apparentium," 150. 
Muler, Nicolas, his "Astrononiia In- 

staurata," 419. 
Mulford, his "Republic of God," 503. 
Mullach, his "Fragnit. Philos. Grsec," 

379, 519. 
Miillenhoff und Scherer, their " Denk- 

maler deutsche Poesie und Prosa aus 

VIII-XII Jahrh.," 294. 
Miiller, Julius, "Die Christ. Lehre von 

der Siinde," 248 ; — Max, " Lectures 

on the Science of Language," 764, 765. 
Mundy, the blind sculptor, 747. 
Musfeus, Johannes, his "De Luminis 

Naturse," 587 ; his " De usu principi- 

orum rationis et philosophise in con- 

troversiis theologicis," 587, 590. 
Musaaus, his "poem of love and 

death," 211. 
Mystics, mediaeval, 576, 728. 

" Nation, the," 764. 

" Naturals, " 341. 

Nature, copies after, what ? 353 ; an 
aggregate of monads, 722 ; conserves 
"the same force," 731; conserves 
" the same total direction," 731. 

Naude, Gabriel, his " Apologie des 
Grands Hommes Soupconnes de 
Magie," 278; founder of " Biblio- 
theque Magazine," 580; Naudeana, 
580. 

Neander, his " History of the Christian 
Religion and Church," 345, 443, 444, 
590. 

Neff, L., his " G. W. Leibniz als Sprach- 
forscher und Etymologe," 304, 376. 

Nerves, " end organs "of, 739 ; specific 
energy of, 739. 

Newton, Sir Isaac, 233; his "Prin- 
cipia," 440; first to apply infinitesi- 
mal calculus to physics, 440; his 
" Optics," 443 ; almost a Berkeleyan, 
773. 



Niam-niam, the, 341. 

Niceron, J. P., his " Memoires d 'hom- 
mes," 587. 

Nichol, John, his " Bacon," 306. 

Nicole, Pierre, 418, 530; his "L'Art 
de Penser," 531 ; his "Essais de 
Morale," 531 ; his " Unite de l'egiise 
ou refutation du nouveau Systeme 
de Jurieu," 531. 

Nihus, Bartholomew, his controversy 
with Vedel, 587. 

Nithard, his " Historia de dissidio fili- 
orum Ludovici Pii," 294. 

Nolen, his "Leibniz, LaMonadologie," 
511 ; his " Quid Leibnizius Aristoteli 
debuerit," 753. 

Nominalism, 623. 

Nominalists, 382. 

Nourisson, M., his " La Philosophie de 
Leibniz," 752, 775. 

Nous of Plato, 555, 723; of Aristotle, 
555. 

" Nouvelles de la Republique des 
Lettres," 50, 334. 

Obreption, 276; Leibnitz's definition 

of, 762. 
Occam, William of, 450; develops 

Nominalism in form of Terminism, 

382, 588. 
Olicelwcns, 286. 

Oldenburgerus, Philippus Andrea, 650. 
Oleum Martis et Veneris, 324. 
Olle-Laprune, his "La Philos. de 

Malebranche," 421. 
Onesimus, " adhuc in vino pruden- 

tior," 762. 
" Ontosopbia," 303. 
Order, the historical, 470 ; the natural 

or logical, 470. 
Ordo prxdicamentalis, 322. 
Ordonez, Garcia, 399. 
Origen, a believer in pre-existence, 248 ; 

on " Visio Beatifica," 575. 
" Orlando, Furioso," 399; " Innamo- 

rato," 398. 
Orphica, 153. 
Ostensives, 491. 

Otfrid, his "Life of Christ," 294; in- 
troduces rhyme, 295. 
Oixria, in Aristotle, 349. 
Ovid, his "Tristia," 56, 729; his 



INDEX C 



853 



"Metamorphoses," 68, 190,733; his 
"Heroides," 211; his "Fasti," 598. 

Pajon, Claude, his view of conversion, 
595. 

Palfyn, Jean, 351. 

Panretius, 261. 

Pandects, see Corpus Juris Civilis. 

Pappus of Alexandria, 521 ; his " Lem- 
mata," 465; his " Synagoge," 521; 
his explanation of analysis and syn- 
thesis, 521. 

Paracelsus, Theophrastus, 645; his 
" Philosophise Sagax," 730; " De 
Nymphis, Sylphis, Pygmseis et Sala- 
mandris," 730. 

Pardies, Ignace Gaston, 676. 

Uapprjcria (parrhesia) , 223. 

Pascal, founder of Calculus of Proba- 
bilities, 213; on equitable division 
of stakes in games of chance, 213; 
his " Lettres Provinciales," 418, 749. 

Pasch, G., on "De novis inventis," 
521. 

Passion in spirit, what? 756; its rela- 
tion to pain, 756 ; in bodies, 756. 

Paul, Hermann, 292; his " Principien 
der Sprachgeschichte," 292 ; his 
"Grundriss d. germ. Philologie," 
295, 296. 

Paulus, on source of rules, 487; his 
" Sententiarum," 534. 

Pausanias, quoted, 390. 

" Peccatum originale," 594. 

"Pellucid, the," in Aristotle, 321. 

Penjon, his "De Infinito apud Leib- 
nitium," 750. 

Penn, William, 602. 

Penzler, M., his "Die Monadenlehre 
und ihre Beziehung z. griech. Phi- 
losophie," 752, 753. 

Perception and apperception, 136. 

Perfectibility, 755; relation of lumi- 
nous pleasures to, 755. 

Peripatetics, 362, 455. 

"Perles de De Sluse," denned, 768. 

Persius, his " Satires," 264, 272. 

Personality, double and alternate, 760. 

Pertz, his " Monumenta Germanise 
Historica," 294. 

Peters, F.H., translator of "Aristotle," 
285. 



Petitio principii, 84. 

Petronius, " Satyricon," 204, 482. 

Petrus, Hispanus, 322. 

Pfleiderer, O., on Boehme, 298; his 
"Eeligionsphilosophie," 249, 298, 
503, 553, 584, 598. 

" Phantasies," how to render the term, 
445. 

Phantasm, 445, 459; Hobbes' use of, 
769. 

Phenomena, connection of, 422; pro- 
duces certainty in sense-knowledge, 
422; verified by truths of reason, 
423. 

Philo, 598, 732 ; on pre-existence. 248 ; 
on " Visio Beatifica," 575. 

"Philosophia Altdorfiana," 635. 

Photinians, 586. 

" Physical," its occasional meaning in 
Leibnitz, 261. 

Piccart, Michael, 636. 

Pichler, his "Die Theologie des Leib- 
niz," 511, 532, 554, 579. 

Hlva^ of Cebes, its genuineness, 436. 

Piper, P., an editor of " Otfrid," 295. 

Pisani, Ottavio, 764. 

Planck, M., his "Das Princip der 
Erhaltung der Energie," 775. 

Plato, 66; his " Meno," 78; his 
"Phaedo," 170, 240, 436; his "Phse- 
drus," 192, 250, 598 ; on pre-existcnce, 
248,768; his method of teaching, 272 ; 
his " Cratylus," 291,292,299; e i8os 
in, 349; his "Symposium," 390; 
Leibnitz's opinion of, 416 ; on im- 
mediate intuition, 575; his "Ion," 
598; his "Timseus," 598; Leibnitz 
compares himself to, 723; his doc- 
trine of reminiscence, 726 ; his 
world-soul, 732, 768. 

Plautus, "Menoechmi," 226. 

Pleasure, according to Aristippus, 518. 

" Pliable," the epithet explained, 723. 

Pliny, the Elder, " Historia Natur- 
alis," 316. 

Plotinus, 598; on ecstatic intuition, 
575 ; his world-soul, 732. 

Plutarch, 476, 598; his " De Fato," 
476; his "Moralia," 476, 551; " De 
Facie in orbe lunse," 551; on moon- 
dsemons, 551; his " Placita Philo- 
sophorum," 724. 



854 



LEIBNITZ'S CRITIQUE OF LOCKE 



HueOfia, Cremer upon, 289. 

" Pneumatics," as a term in mental 
philosophy, 3(32. 

Pneumatology, 50, 363. 

Pneumatosophy, 363. 

Poe, Edgar A., refers to Gonsales, 342. 

Poiret, Pierre, biographer of Antoi- 
nette Bourignon, 599 ; his " G3co- 
nomie de la Nature," 599. 

Poisson, his " Recherches sur la Prob- 
abilite'," etc., 213. 

Polemo, statement of Stobaeus con- 
cerning, 518 ; his philosophy, 518. 

Pollock, F., his " Spinoza, his Life and 
Philosophy," 345, 733. [315. 

Polyhedra, the only possible regular, 

Poinponazzi, Pietro, 581; his " Trac- 
tatus de Immortalitate Animi," 581. 

Pomponius Sextus, 241, 486. 

Poniatowa, Christine, a visionary, 604 ; 
her death from chagrin, 604; her 
visions rendered into Latin by 
Comenius, 604. 

Porphyry, his " Tabula Logica," 322; 
his EtVo7W7^, 322. 

Port Royalists, 530. 

Portugal, Sea of, 134. 

Possible, everything which is, an ob- 
ject of intelligence human or divine, 
763. 

Poste, his " Gaius, Elements of Roman 
Law," 329. 

Potestas Diaboli, infants under, ac- 
cording to Augustine, 594. 

Pouchet, F. A., his "Histoire des Sci- 
ences naturelles en moyen age," 371. 

Power distinguished by Leibnitz from 
force, 751. 

PrsedicaMlia, Prsedicamenta, 322. 

PrsBScriptiones, 531. 

Prantl, his " Gesch. d. Logik," 116, 322, 
349, 382, 408, 415, 456, 488, 515, 565, 
588, 590, 765, 770. 

Pre-existence of souls, 248; no expla- 
nation of the origin of sin, 248, 249. 

Preller, his " Griech.Mythologie," 390. 

Premise, when the philosophical is 
general and the theological is par- 
ticular, what is to be done ? 761. 

"Prince, A great," Leibnitz's expec- 
tation from one in the future, 629. 

Priscillianists, 345. 



Probabiliorism, 418. 

Probabilism, 418. 

Probabilities, Calculus of, 213. 

Probability, Aristotle's definition of, 
214; logic of, 417. 

Proclus, Diadochus, 93, 108, 465; the 
" schoolman of Neo-Platonism," 
108; his "Treatise on the Sphere," 
108; his "Institutes of Theology," 
108; his "In primum Euclidis Ele- 
mentorum librum commentarii," 
108, 463; Leibnitz's opinion of, 416. 

Procopius, alleged author of " Anec- 
dota," 542. 

Proculus, 762. 

Prolepses, Stoic doctrine of, 724. 

"Promoter," defined, 757. 

Proof, indirect, what ? 406. 

Propositions, " weaker," 515. 

Propria, 455. 

Proprium, 455. 

Prosthaphaeresis, 540. 

Prosyllogism, 404. 

Proverbs, Book of, 437. 

Pucci, Francesco, 593; his "De fide in 
Deum," 593; his views of universal 
grace, 593. 

Pufendorf , Samuel, 435 ; his " Ele- 
menta Jurisprudential universalis," 
436; his " De Statu imperii German- 
ici," 436; his "De jure naturae et 
gentium," 436; Leibnitz severely 
criticises, 436. 

Piinjer, his " Gesch. d. Christliche Re- 
ligionsphilosophie," 298, 581, 582, 
584, 587, 589, 607, 761, 769. 

Pythagoras, 379 ; his " Symbols," 379 ; 
literature upon, 474. 

Pythagoreans, 248. 

" Quadratura Arithmetica," 425. 

Quadrivium, 628. 

" Qualitates occultse," 729. 

" Qualities, inexplicable," 729. 

Quartan fever, 488. 

" Quarto Modo, in," 455. 

Question, how "begged" in the as- 
sumption that because we are not 
conscious of ideas, therefore we do 
not think, 738. 

Qui jure suo utitur nemini facit in- 
juriam, 492. 



INDEX C 



Quietists approach Averroists in doc- 
trine, 728. 

Quintic equations, as to possibility of 
their solution, 571. 

Quintiliau, his " Institutes," 766. 

Quodlibetarise questiones, 419. 

Quodlibetum, 419. 

Quolibet, 419. 

Rabbiuage, 372. 

Rabelais, 399. 

Raey, Jean de, 632; his " Clavis Phil- 
osophica," 633. 

Ramists, 398, 408. 

Ramus, Petrus, 398, 408; opposes 
Aristotelianism, 408; his " Animad- 
versiones Aristotelicse," 408; his 
" Institutiones dialecticae," 408. 

Raspe, 510, 532. 

"Ratio" a department of the scho- 
lastic "threefold source of knowl- 
edge," 724. 

Real and physical, their relations, 261. 

Realism, Locke's sensistic, set forth in 
sharp outline, 567. 

Realists, 349, 382. 

Reality, demonstrable, 319; how- 
known, 766. 

Reason, how used by Locke and Leib- 
nitz, 555 ; can apprehend the super- 
natural as fact, 579; and faith, 579; 
its chief end practical, 754. 

Rebus, 453. 

"Recueillement," its translation, 165. 

Refiks, 197. 

Reflection, 726. 

Regiomontanus, his discovery, 571. 

Re'gis, Pierre Sylvain, an empiric Car- 
tesian, 348, 633; his " Cours entier 
de philosophie," 348; censured by 
Descartes, 348. 

Regius, see Roy. 

" Regulative," 517. 

Reimarus, H. S., his " Allgemeine Be- 
trachtungen iiber die Kuusttriebe 
der Thiere," 725. 

Reimer, G., 102. 

Reinesius, Thomas, physician and phi- 
lologist, 372. 

Reinkens, J. H., enquires " ' Anecdota ' 
sintne scripta a Procopio," 542. 

Reiser, Anton, 649. 



Reisland, O. K., 102. 

Relation, two kinds of, 401; what? 
759. 

Remembrance, 734. 

Reminiscence, 734; Platonic view of, 
726. 

Renan, E., his "Averroes et l'Aver- 
roisme," 774. 

Representationism, 382. 

Res, incorporates, 329; judicata, 534, 
602. 

Revelation, Divine, Langley on, 32, 
195; Locke assumes, 474; Leibnitz, 
while insisting on rational element 
in theology, admits possibility, and 
discusses method and actuality, of, 
474; its truth rests on "veracity of 
God," 474. 

Revelation, universal, 474. 

Revius, J., 633. 

"Revue des deux Mondes," 590. 

Ritschl, his " Gesch. d. Pietismus," 
602, 649. 

Robertson, G. Croom, 69; his 
"Hobbes," 93, 450; his "Philos. 
Remains," 733, 770. 

Roberval, Gilles Personne de, 107, 
127; his method for construction 
of tangents, 108; Descartes' esti- 
mate of, 466. 

Robinson, E. G., his " Principles and 
Practice of Morality," 90, 95, 262, 
752, 753, 754; his "Christian The- 
ology," 594, 606; his "Lectures on 
Psychology" (MS.) quoted, 741-747; 
on " Moral Law in its Relations to 
Physical Science and to Popular Re- 
ligion," 761. 

Rohault, James, his " Physica," 233. 

Romania rustiea lingua, 294. 

Romanes, his "Animal Intelligence," 
725; his " Mental Evolution in Ani- 
mals," 725. 

Romans, 2: 15, 89. 

"Rompu, le," 750. 

Rorario, Geronimo, 732. 

Rothwalsch, 292. 

Roy, Hendrik van (Regius), rejected 
by Descartes, 633 ; his notions of 
soul, motion, and rest, 633 ; his. 
" Fundamenta Physicse " and his 
" Philosophia Naturalis," 633. 



856 



LEIBNITZ'S CRITIQUE OF LOCKE 



Ruach (? n ), defined, 289. 

Ruland, Martin, his " Lexicon Al- 

cheraise," 324. 
Russia, Leibnitz's plan for study of its 

languages, 765. 



i, Hassan Ben, 197. 

Sacy, De, his " Memoires de l'lnsti- 
tute," 197. 

Sadness, its nature, 735. 

Saint- Vincent, Gregoire de, his " Opus 
geometricum quadrature circuli et 
sectionum coni," 573. 

Sainte-Maure, Charles de, edits " Del- 
phi n Classics," 605. 

Salmasius, 371. 

Sandars, his " Institutes of Justinian," 
329, 431, 487. 

Sanseveriuo, his "Dynamilogia," 382. 

Santon, 89. 

"Savage," 85. 

Scaliger, Joseph Justus, reconstructs 
"Chronicle of Eusebius," 106; — Jul- 
ius Csesar, his " Exotericae Exercita- 
tiones," 106. 

" Scaligeraua," 107. 

Schaarschmidt, 125, 128, 150, 152, 168, 
214, 242, 272, 311, 316, 317, 321, 330, 
339, 362, 371, 394, 399, 408, 413, 415, 
424, 436, 445, 459, 465, 466, 476, 492, 
499, 504, 510, 521, 543, 555, 569, 582, 
588, 589, 590, 601, 606, 622, 623, 723, 
724, 725, 726, 727, 728, 729, 730, 731, 
733, 734, 735, 736, 738, 739, 741, 749, 
752, 754, 755, 756, 757, 758, 759, 763. 

Schaff, P., edits " Nicene and Post- 
Nicene Fathers," 516. 

Schelling, his relation to Boehme, 
298. 

Scherer, W., " Gesch. d. deutsch- 
Literatur," 295, 296. 

Schering, E. J., edits Gauss's works, 
152. 

Scherz and Schilter, joint editors of 
" Thesaurus antiouitatum teutoni- 
cum," 295. 

Schilter, John, Leibnitz refers to, 295; 
his death a note of time as to revi- 
sion of the " New Essays," 765. 

Schlee, E., his " Der Streit des Dan. 
Hofmann fiber die Verhaltniss der 
Philosophie mid Theologie," 582. 



"Scholarch," 518. 

" Scholastic, The last great," 494. 

Scholastic philosophy, its threefold 
source of knowledge, 724. 

Schooten, F. van, 468; his " Exercita- 
tiones Mathematical, " 539. 

Schopenhauer, 298. 

Schubert, H., 425. 

Schuchardt, B., 372. 

Schurman, J. G., his "Ethical Import 
of Darwinism," 90, 97. 

Schurman, Anna Maria v., 602. 

Schurtzfleisch, Konrad S., 650. 

Schwabe, Ludwig, 244. 

Schweinfurth, G. A., on men with 
tails, 341; his " Im Herzen vom 
Afrika," 341. 

Schweizer, his " Central-Dogmen," 
595. 

" Sciences as many as truths," 623. 

Scientific consideration, its limits ac- 
cording to Aristotle, 488. 

Scotus, Johannes Major, 322 ; — Johan- 
nes Duns, 381 ; — Michael, 278. 

Sculpturing by sense of touch, 747. 

Scudery, Mile., her "Clelie, Histoire 
Romaine," 223; Leibnitz on, 757. 

Seckendorf, Veit Ludwig von, his 
" Commentarius historicus et apolo- 
geticus de Lutheranismo," 543 ; Leib- 
nitz's opinion of, 544. 

"Self, The," defined, 700; "the phe- 

• nomenon of," 760; how related to 
consciousness, 760; constitutes iden- 
tity, 760 ; a real entity, 760. 

Selver, D., his "Der Entwicklungs- 
gang d. Leibniz. Monadenlehre bis 
1695," 723, 775. 

Semi-Ramists, 408. 

Seneca, "De Tranquilitate," 492. 

Sennert, Daniel, introduces chemistry 
into curriculum at Wittenberg, 487 ; 
maintained that souls of animals 
were immaterial, 487 ; his " Institu- 
tiones medicse," 488 ; attempts to 
unite principles of Galen and Para- 
celsus, 488. 

Sensation, how related to nerves, 739. 

Sense-impressions likely composite, 
but at present irresolvable, 317, 751. 

Sense-knowledge, confused, 317; 
classification, 317. 



INDEX C 



857 



Sense-perception, when possible, 741. 

Senses, when, according to Idealists, 
we have truth by, 512. 

Sensitive, 417 ; — soul, 380. 

Serarius, Nicolas, 443. 

Serenus of Antissa, his "De sectione 
Cylindri et Coni," 465. 

Series, infinite, of Leibnitz, 424, 723. 

Seth, James, his article " Roots of Ag- 
nosticism," in " New World," 773. 

Shakespeare, his " Midsummer Night's 
Dream," 770. 

Shedd, W. G. T., his " History of Chris- 
tian Doctrine," 594. 

Sheikh-al Jebal, 197. 

Ship, the sacred, of the Athenians, 
240. 

Siebeck, his " Gesch. d. Psychologie," 
769. 

Sifrid, on Frisian antiquities, 546. 

Sigogne, Francois de, 107. 

Sigwart, W., "Die Leibniz'sche Lehre 
v. d. prastabilirten Harmonie," 731. 

Simonides, inventor of mnemonics, 
214. 

Sleidan, John, his " Commentariorum 
de statu religionis et republican, 
Carolo Quinto Crcsare," 114. 

Sluse, Rene Francois Walter de, his 
" Mesolabium," 387 ; his treatment 
of equations of the third and fourth 
degree, 387; his "perles," 768. 

Smith, his "Dictionary of the Bible," 
327; and Wace, their "Dictionary 
of Christian Biography," 345, 443, 
444, 531, 618. 

Societe des anciens textes francais, 
Album of, 294. 

Socinus, F., 593. 

Socrates, 595; his daemon, 598. 

Socratic school of philosophy, 93. 

Sohm, Rudolph, his "Institutes of 
Roman Law," 766. 

Solidity, in its conception the views 
of Locke and Leibnitz come to 
clearest antithesis, 741. 

Soner, Ernst, 635. 

Sophie Charlotte, Queen, 239. 

Soul, what ? 722. 

Soulhood, universal, 732. 

Souls, three forms of, in scholastic 
philosophy, 380. 



Space defined, 152. 

" Spatium fit ordo existentium phseno- 
menorum," 128. 

Species, its meaning, 314; intentional, 
381, 382; real, 381, 382; sensible, 
381; intelligible, 381. 

Spe'cieuse generate, 292, 375. 

Spectroscope, the, 549. 

Spencer, Herbert, 274. 

Spener, Philip Jacob, 649. 

Spenser, " Faerie Queen," 770. 

Spermatic logos, 591. 

Speusippus, 518. 

Spinoza, 102, 192, 723 ; offered chair of 
philosophy at Heidelberg, 102; his 
"Ethica," 148, 192, 502, 732; his 
" Tractatus Theologico-politicus," 
289 ; his fatalism, 462 ; letter to De 
Vries, 502; maintains ontological 
argument for existence of God, 502 ; 
his " Korte Verhandeling van God," 
504, 754, 755 ; his reference to Bacon, 
526; reference to Descartes, 526; on 
probabilities, 539, 540; receives a 
letter from Fabritius,723; his " Oin- 
nis determinatio est negatio," 750; 
on value of faith in a future life 
upon this one, 755 ; monism of, 757. 

Spirits incomprehensible to senses and 
imagination, 721; of the elements, 
730. 

Spiritual things prior to material, 721. 

Spiritus, 289 ; naturse, 382, 768 ; fa- 
miliaris, 730. 

Spitzel, Theophil Gottlieb, 649. 

Spontaneity of soul, 733. 

Sprengel, K., his " Beitrage z. Gesch. 
des Medecin," 408; on Sennert, 488. 

Stamm, his " Ulfilas," 296. 

Stegmann, Christopher, his "Dyas 
Philosophica," 585; — Joachim, 
mathematician and theologian, 585 ; 
— Joshua, his " Ach bleib' mit 
deinem gnade," 586. 

Stein, Ludwig, his " Leibniz und 
Spinoza," 69, 102, 242, 349, 504, 652, 
653, 655, 731. 

Steinthal, H., his " Einleitung in die 
Psychologie und Sprach-wissen- 
schaft," 292. 

Stephanus, his "Thesaurus Linguae, 
Graecae," 476. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Stewart, J. A., his " Notes on the Nico- 
macheau Ethics of Aristotle," 753. 

Stillingfleet, Bishop Edward, 54; con- 
troversy with Locke, 54, 55, 56. 

Stobaeus, "Eclogse Physicse," 518. 

Stockl, his " Gesch. d. Philos. d. Mittel- 
alters," 116, 278, 298, 349, 380, 382, 
408, 415, 421, 494, 503, 566, 581, 588, 
590, 592, 632, 635, 615, 646, 730, 732. 

Stoic philosophers, 261, 729. 

" Stomachi Janitor," 67. 

Strabo, his " Geographica," 345; on 
fertility of mules, 345. 

Strauch, Johann, his "Lexicon parti- 
cularum juris," etc., 365. 

" Strong-minded," 728. 

Struve, F. W., edits the " Bihliotheca 
juridica " of Lipenius, 626. 

Struyck, Nicolas, on De Witt's reason- 
ing on Insurance, 540; his " Inlei- 
ding tot het algemeine geography," 
540. 

Sturm, Johann Christoph, 705. 

Suarez, Francisca, his "De Anima," 
382; his "Tract, de legibus ac Deo 
legislatore," 494. 

Substance, idea of the individual, its 
development in mind of Leibnitz, 
101 ; list of Leibnitz's papers on, 
154 ; what, according to Leibnitz, 
227 ; what, according to Aristotelian 
scholasticism, 227 ; changing yet nu- 
merically the same, 243 ; first in 
sense of Aristotle, 311 ; first, irpuiT-r] 
ovala, 311, 349; corporeal, what? 722; 
its absolute spontaneity, 739 ; opin- 
ions of Locke and Leibnitz regard- 
ing, 749; Leibnitz, in speaking of, 
accommodates himself to linguistic 
usage, 759 ; Leibnitz's view of, 760. 

" Succedaneum," 417. 

Si'\Xo7t(T/x6s, two kinds of, 565. 

Sulpicius Severus, 345. 

^u/xBtPrjicoTa, 453. 

Su/x7TJ'oia TroLfTa, 476. 

Iivjxttvovs, universe, 476. 

Supernatural, its relation to reason, 
579. 

Surd, an obsolete mathematical term, 
750. 

Suter, H., his "Gesch. d. math. Wis- 
senschaften," 527. 



Swift, his "Gulliver's Travels," 342; 

did he plagiarize ? 399. 
Syllogism, fourth figure of, 408; al] 

its terms not always expressed in 

argumentation, 481; dialectic, 564; 

apodeictic, 565. 
Symonds, J. A., his "Studies of the 

Greek Poets," 211, ibid. 3d ed., 755 ; 

his "Renaissance in Italy," 399, 

415. 
Synthesis, explained by Pappus, 521. 
" System, New," commented on, 731. 

" Tabula,'' "logica," 322; "rasa," 724. 

Tacitus, "Annales," 91, 327. 

Tails, men with, 341. 

Tartaglia, his contest with Fiore, 572. 

Taste through nose, 739, 740. 

Taylor, Thomas, 108. 

Technical schools advocated by Leib- 
nitz, 628. 

Teeth transmit sound ? 740. 

Temperament, what? 362. 

" Tempus tit ordo successivorum," 128. 

Ten Brink, B., his " Early English Lit- 
erature," 295. 

Teotisca, lingua, old German, 294. 

Terence, "Andria," 226; " Phormio," 
327; "Eunuchus," 459; "Heauton- 
timoroumenos," 492. 

Term, middle, 481; the general, 511. 

Terminism, 588. 

Tertullian, 531; his " De Prsescripti- 
one Hrereticorum," 531; his "De 
Carne Christi," 582; his "credibile 
est quia ineptum est," etc., 582. 

Teuffel, his "Gesch. d. Rom. Lit.," 
244. 

Thales, 463. 

" Tbeodicee, Essais de," see Leibnitz. 

Theology, Natural, made a depart- 
ment of Metaphysics by Scholastics, 
496. 

Theophrastus adds to first figure of 
the Syllogism, 408. 

"Theseus, ship of," 240. 

Th.il, Arnaud du, the personator of 
Martin Guerre, 310. 

Thomas, the Pseudo-, 322. 

Thomasius, G., his "De Controversia 
Hoffmanniana," 582;— Jacob, pro- 
fessor of Philosophy at Leipzig, 



INDEX C 



859 



605; his "De officio hominis circa 
notitiam futurorum contingenti- 
um," 606; his " Origiues historise 
philosophic* et ecclesiasticae," 606 ; 
— Christian, son of above, and ed- 
itor of his works, 606. 

Thompson, Archbishop, 455. 

Thorpe, B., his " Csedmon's Metrical 
Paraphrase," 295. 

Thought, objects of, classified, 148; 
right, leads back to God, 505 ; may be 
distinct, yet not clear, 754 ; how the 
word is employed by Leibnitz, 756. 

" Thought-necessity," 281. 

Tichborne case, 310. 

Time, defined, 128 ; — of writing " New 
Essays," 532; of revising "New 
Essays," 765. 

Tiraboschi, his " Storia della Lettera- 
tura Italiana," 415, 593. 

Todbunter, Isaac, his " History of the 
Theory of Probability from Pascal 
to La Place," 213, 539. 

Tolome'i, Giovanni Battista, 705. 

Tonnies, F., his " Leibniz und 
Hobbes," 450. 

Torricelli, Evangelista, invented mer- 
curial barometer, 127 ; discovered 
quadrature of cycloid, 127; his "De 
motu gravium naturaliter accele- 
rato," 127jB» 

" Tot scientrai quot veritates," 623. 

" Transcendent " in mathematics, 750. 

Trebatius, 492. 

Trendelenburg, his " Ueber Leibniz- 
ens Entwurf einer allgemeinen Char- 
akteristik," 292, 375; his "Ueber 
d. element d. definition in Leibniz. 
Philosophie," 317 ; his " Histor. Bei- 
trage z. Philos.," 753, 765. 

Trent, Council of, 114. 

Trew, Abdias, 641. 

Trino, the Decurions of, 520. 

Trithemius, his "Annales Hirsaugien- 
ses," 278; his "Compendium primi 
voluminis annalium de origine re- 
rum et gentis Francorum," 546. 

Trivium, 628. 

True, the, is the thinkable, 281. 

Truth, Aristotle on, 281 ; of two kinds, 
404 ; Leibnitz on its definition, 445 ; 
Locke's and Leibnitz's views of, 



452 ; Schaarschmidt's definition of, 

762. 
"Truth, twofold," the, 581. 
Truths, of fact and of reason, 462, 

493; of reason, their genesis, 725; 

necessary, 725 ; factual, 725. 
Tulloch, his "Rational Theology and 

Christian Philosophy in England in 

17th Century," 767. 
Tulp, Nicolas, his " Observationum 

Medicarum," 244. 
Tutiorism, 418. 
" Twofold Truth," 581. 

Ueberweg, his "Hist, of Philosophy," 
116, 332, 763, 769; his " Grundriss 
der Gesch. der Philosophie," 5; 
-Heinze, 332, 408, 503, 516, 592. 

Ulfilas, 296. 

Ulpianus, 486. 

Ulrich, J. H. F., German translator 
of the French and Latin works of 
Leibnitz, Raspe's ed., 344. 

" Unconscious Mental States," 727. 

" Un Je ne say quoi," 128. 

Uncle of Leibnitz, 365. 

"Understanding," 723. [310. 

Universal, the, does it really exist? 

Universe not a whole, 155. 

Uppstrom, edits "Codex Argenteus," 
296. 

Ursinus, Joseph, 767. 

Utile and honestum, 261. 

Uylenbroek, P. I., 767; his "Christ. 
Hugenii aliorumque celebrium exer- 
citationes mathematical et philo- 
sophica;," 767. 

Vacuum, Descartes' view of, 127 ; for- 
marum, 334 ; defined, 740. 

Valla, Laurentius, explodes the alleged 
"Donation of Constantine," 415; 
his " Disputationes contra Aristote- 
licos," 415; his " De voluptate et 
vero bono," 415 ; his " Libero arbit- 
rio " ; his " Elegantise Latinse Lin- 
guae, " 415. 

Van Helmont, 67, 242. 

Vanini, Lucilio, 648. 

Vassan, 107. 

Vaughan, Alfred, his " Hours with the 
Mystics," 298. 



LEIBNITZ'S CRITIQUE OF LOCKE 



Vayer, Francis de la Mothe le, his 
" De la Vertu des Pa'iens," 593. 

Vedelius, 587; his "Rationale Theo- 
logicum," 587 ; his controversy with 
Musaeus, 587, 761. 

Vega, Garcilasso de la, his " Commen- 
tarios Reales," 89. 

" Vegetative soul," the, 380. 

" Vehicles, aerial," of spirits, 380. 

Veitch, J., translator of Descartes, 
127, 348, 483. 

Velleitas, 168. 

Yelleite, its rendering, 168. 

Venn, J., his " Logic of Chance," 214. 

Venturi, his " Commentarii sopra la 
storia et le teorie dell' ottica," 443. 

Vergil, his " Georgics," 200, 211, 727; 
"iEneid," 300, 415, 598, 614; "Ec- 
logues," 614. 

" Vernunft, die," its Kantian accepta- 
tion, 723. 

Versura, 326. 

Vertunien, Francois, 107. 

Verulamius, 526. 

Vibration Theory of Light, 639. 

Viete, Francois, 468 ; his improve- 
ments in algebraical operations, 468 ; 
lays down the principle of " homo- 
geneity, " 468; his "Opera mathe- 
matical' 468. 

Vincent of Lerins, his " Adversus 
novitates hasreticorum commonito- 
rium," 617; author of the dictum, 
"Quod semper, quod ubique, quod 
ah omnibus creditum est," 617. 

Viotto, Bartolommeo, his " De balne- 
orum naturalium virihus," 520 ; his 
"Demonstrationum in methodum 
medendi," 520; Conring's opinion 
of, 520. 

Virgil, St. (Fergil),443. 

"Virtual," 726. 

Virtue, on what its usefulness de- 
pends, 495 ; Kant's definition of, 754 ; 
E. G. Rohinson's definition of, 754. 

Vision, the Beatific, its nature, 575; 
history of idea, 575. 

Voe't-Schoock-Descartes controversy, 
633. 

Volitio imperfecta, 168. 

Voltaire in the Maupertuis-Konig con- 
troversy, 713. 



Vopiscus, in " Scriptores Hist. Au- 
gust.," 263, 761. 

" Vorstellen," 756. 

" Vorstellung," 330, 736, 756. 

Vortices, theory of, according to Des- 
cartes, 552, 613, 727. 

Vossius, Isaac, 107. 

Waitz, his "Das Leben des Ulfilas," 
296. 

Wallace, E., his " Outlines of the Phi- 
losophy of Aristotle," 96, 156, 157, 
214, 281, 291, 311, 312, 320, 321, 349, 
421, 488, 565, 751, 770; his "Aris- 
totle's Psychology in Greek and 
English," 281, 321; — W., his "Epi- 
cureanism," 421; his "Logic of 
Hegel," 750, 766. 

Wallis, John, 677. 

Walpole, F., his "Ansayrii," 197. 

Walton, Isaac, 566. 

Warr, G. C. W., 244. 

Watson, John, his "Philosophy of 
Kant in Extracts," 128; his article 
"Leibnitz and Protestant The- 
ology," in " New World," 770, 773. 

" Weaker or Worse," in Logic, 515. 

Weigel, Erhard, engaged on Calendar, 
435 ; a school reformer, 435 ; his 
" Arithmetique de la Morale," 435; 
Leibnitz upon, 435. 

Weil, his " Gesch. d. Chalifen," 197. 

Werner, K., his " Suarez," 494. 

Wetzer und Welte, their " Kirchen- 
lexicon," 600. 

White, Thos. (Anglus), 634; his "In- 
stitutionum Peripateticarum ad 
mentem K. Digbsei," 634; his "De 
Medio Animarum Statu," 775; cen- 
sured by Parliament, 775 ; his " Re- 
sponsio ad duos theologos de Medio 
Animarum Statu," 775. 

Whitney, W. D., his "Language and 
the Study of Language," 291, 292. 

Wilkin, " Gesch. d. Kreuzziige," 197. 

Wilkins, Bishop John, his " Essay 
towards a Real Character and a 
Philosophical Language," 292. 

" Will, vigor of," 754. 

Willensneigung , 168. 

Willkiir, 752. 

Windelband, his "History of Philos- 



ophy," 488, 502, 503, 516, 576, 581, 
588, 721, 727, 732, 733, 753. 

Winer, his " Handbuch d. Theol. Lit.," 
586, 587. 

Winfrid, see Boniface. 

Wisdom, Leibnitz's definition, 754. 

Witsen, Nicolas, sends specimens of 
the language of the Hottentots to 
Leibnitz, 290; his " Architectonica 
nautica non-antiqua," 737. 

Witt, John De (Pensionary), 426; his 
" Elementa linearum curvorum," 
427; his report on annuities to 
States-General, 540. 

Wohlwill, E., his " Jungius," 636. 

Wolf, Christian, 303; his "Kurzer 
Unterricht v. d. vornehmsten math. 
Schrift," 463; made existence the 
source of its concept, 741 ; ac- 
cepts Leibnitz's definition of truth, 
763; his definition of philosophy, 
763; his " Psychologia Empirica," 
764. 

Wolffhart, Conrad ( Lycosthenes ) , 
548. 

World-soul, 732. 

Wrangham, D. S., his "Liturgical 
Poetry of Adam St. Victor," 603. 

AVren, Sir Christopher, 346, 677. 

Wright, J., his " Primer of Gothic," 
296. 

Wundt, William, his " Lectures on 



Human and Animal Psychology," 
725. 

Xenocrates, 518. 

Xenophon, "Memorabilia," 240. 

Xylander, 571. 

Yvon, Pierre, his " Abrege precis de 
la vie et de la conduite et des vrais 
sentiments de feu M. de Labadie," 
602. 

Zabarella, Jacopo, 635. 

Zachary, Pope, 444. 

Zeller, his " Outlines of the History of 
Greek Philosophy," 65, 93, 96, 108, 
156; his " Philos. d. Griech.," 108, 
156, 261, 277, 285, 311, 312, 320, 321, 
349, 362, 379, 383, 408, 421, 436, 463, 
465, 474, 488, 496, 518, 519, 565, 576, 
598, 724, 750, 751, 753; " Gesch. d. 
deutschen Philos.," 363. 

Zigliara, his "Summa Philosophica," 
382. 

Zimmermann, his " Leibniz und Les- 
sing," 584. 

Zwerger, M., his " Die lebendige Kraft 
unci ihr Mass," 775. 

Zwinger, Theodore, 311; his "Thea- 
trum Vitas Humanas," 548. 

Zwingli, Ulrich, 592, 595 ; his "Christ. 
Fidei brevis et clara expositio," 595; 
his " De Providentia," 595. 



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